That's right, and it's probably not the end of it. I'll just claim that
I have no idea how to create a proper user interface for this, so I'm
creating multiple partially-orthogonal, of which some may work better in
each of its special use cases.
Until now, there was --record-file. You get relatively good control
about what is muxed, and it can use the cache. But it sucks that it's
bound to playback. If you pause while it's set, muxing stops. If you
seek while it's set, the output will be sort-of trashed, and that's by
design.
Then --stream-record was added. This is a bit better (especially for
live streams), but you can't really control well when muxing stops or
ends. In particular, it can't use the cache (it just dumps whatever the
underlying demuxer returns).
Today, the idea is that the user should just be able to select a time
range to dump to a file, and it should not affected by the user seeking
around in the cache. In addition, the stream may still be running, so
there's some need to continue dumping, even if it's redundant to
--stream-record.
One notable thing is that it uses the async command shit. Not sure
whether this is a good idea. Maybe not, but whatever. Also, a user can
always use the "async" prefix to pretend it doesn't.
Much of this was barely tested (especially the reinterleaving crap),
let's just hope it mostly works. I'm sure you can tolerate the one or
other crash?
The screenshot command has this weird behavior that it shows messages
both on terminal and OSD by default, but that a command prefix can be
used to disable the OSD message.
Move this mechanism to common code, and make this available to other
commands too (although as of this commit only the screenshot commands
use it).
This gets rid of the weird screenshot_ctx.osd field too, which was sort
of set on a command, and sometimes inconsistently restored after the
command.
The readahead time should be interesting for latency vs. underruns
(which idiot protocols like HLS suffer from).
The total byte usage is less interesting than I hoped; maybe the
frequency at which it samples should be reduced. (Kind of dumb - you
want high frequency for the readahead field, but much lower for byte
usage.)
Of course, the code was copy&pasted from the DS ratio/jitter stuff. Some
of the choices may not make any sense for the new code.
Normally I use the OSC like this: not at all, but have a key binding
that does "cycle osc" to show it. And in that case, I don't really want
it to overlap the damn video.
I could use the zoom/pan options to move the video out of the way, but
this is also sort of annoying. Likewise, you could write a script or so
which does this automatically if the OSC appears, but that's still
annoying, and computing values for these options such that the video is
moved correctly is tricky.
So I added a bunch of options that set explicit video borders (previous
commit), and a option for the OSC to use them (this commit).
Disabled by default, since I'm afraid this is too awkward and
unpolished, especially with OSC default settings.
I'm also using "osc-visibility=always". Effectively, making the OSC
appear will box the video, and making it disappear (by unloading
osc.lua) will restore the video back to normal.
Somewhat similar to the old --cache-file, except for the demuxer cache.
Instead of keeping packet data in memory, it's written to disk and read
back when needed.
The idea is to reduce main memory usage, while allowing fast seeking in
large cached network streams (especially live streams). Keeping the
packet metadata on disk would be rather hard (would use mmap or so, or
rewrite the entire demux.c packet queue handling), and since it's
relatively small, just keep it in memory.
Also for simplicity, the disk cache is append-only. If you're watching
really long livestreams, and need pruning, you're probably out of luck.
This still could be improved by trying to free unused blocks with
fallocate(), but since we're writing multiple streams in an interleaved
manner, this is slightly hard.
Some rather gross ugliness in packet.h: we want to store the file
position of the cached data somewhere, but on 32 bit architectures, we
don't have any usable 64 bit members for this, just the buf/len fields,
which add up to 64 bit - so the shitty union aliases this memory.
Error paths untested. Side data (the complicated part of trying to
serialize ffmpeg packets) untested.
Stream recording had to be adjusted. Some minor details change due to
this, but probably nothing important.
The change in attempt_range_joining() is because packets in cache
have no valid len field. It was a useful check (heuristically
finding broken cases), but not a necessary one.
Various other approaches were tried. It would be interesting to list
them and to mention the pros and cons, but I don't feel like it.
The old implementation didn't work for the OGG case. Discard the old
shit code (instead of fixing it), and write new shit code. The old code
was already over a year old, so it's about time to rewrite it for no
reason anyway.
While it's true that the old code appears to be broken, the main reason
to rewrite this is to make it simpler. While the amount of code seems to
be about the same, both the concept and the actual tag handling are
simpler. The result is probably a bit more correct.
The packet struct shrinks by 8 byte. That fact that it wasted 8 bytes
per packet for a rather obscure use case was the reason I started this
at all (and when I found that OGG updates didn't work). While these 8
bytes aren't going to hurt, the packet struct was getting too bloated.
If you buffer a lot of data, these extra fields will add up. Still quite
some effort for 8 bytes. Fortunately, it's not like there are any
managers that need to be convinced whether it's worth doing. The freedom
to waste time on dumb shit.
The old implementation attached the current metadata to each packet.
When the decoder read the packet, the packet's metadata was made
current. The new implementation stores metadata as separate list, and
requires that the player frontend tells it the current playback time,
which will be used to find the currently valid metadata. In both cases,
the objective was to correctly update metadata even if a lot of data is
buffered ahead (and to update them correctly when seeking within the
demuxer cache).
The new implementation is actually slightly more correct, because it
uses the playback time for the metadata lookup. Consider if you have an
audio filter which buffers 15 seconds (unfortunately such a filter
exists), then the old code would update the current title 15 seconds too
early, while the new one does it correctly.
The new code also simplifies mixing the 3 metadata sources (global, per
stream, ICY). We assume these aren't mixed in a meaningful way. The old
code tried to be a bit more "exact". I didn't bother to look how the old
code did this, but the new code simply always "merges" with the previous
metadata, so if a newer tag removes a field, it's going to stick around
anyway.
I tried to keep it simple. Other approaches include making metadata a
special sh_stream with metadata packets. This would have been
conceptually clean, but the implementation would probably have been
unnatural (and doesn't match well with libavformat's API anyway). It
would have been nice to make the metadata updates chapter points (makes
a lot of sense for the intended use case, web radio current song
information), but I don't think it would have been a good idea to make
chapters suddenly so dynamic. (Still an idea to keep in mind; the new
code actually makes it easier to work towards this.)
You could mention how subtitles are timed metadata, and actually are
implemented as sparse packet streams in some formats. mp4 implements
chapters as special subtitle stream, AFAIK. (Ironically, this is very
not-ideal for files. It would be useful for streaming like web radio,
but mp4 is extremely bad for streaming by design for other reasons.)
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
It seems the so called demuxer cache wasn't really disabled for
sub-demuxers (timeline stuff). This was relatively harmless, since the
actual packet data was shared anyway via refcounting. But with the
addition of a mmap cache backend, this may change a lot.
So strictly disable any caching for sub-demuxers. This assumes that
users of sub-demuxers (only demux_timeline.c by now?) strictly use
demux_read_any_packet(), since demux_read_packet_async() will require
some minor read-ahead if a low level packet read returned a packet for a
different stream.
This requires some awkward messing with this fucking heap of trash. The
thing that is really wrong here is that the demuxer API mixes different
concepts, and sub-demuxers get the same API as decoders, and use the
cache code.
Track switching doesn't run reset_playback_state(), so a track enabled
at runtime during backward playback would lead to a messed up state.
This commit just does a bad code monkey fix to this. It feels like there
needs to be a much better way to propagate this state.
And add simpler aliases for the modes.
I'm not sure how to name things, and the option list is in general full
of different conventions. Some names are shortened, some are explicit
and long.
I guess options that have a chance to be used normally (i.e. not obscure
tuning or debugging) should have a short and convenient names.
In this specific case, play-direction is like a mixture of both. It
should be either playback-direction or play-dir, not shorten one word
but not the other.
The convenience aliases are because I got sick of typing out "backward".
I guess "back" would also do it, but there's no proper antonym (and
maybe it's "wrong" in the strict sense of the word).
Another shitty obscure feature that usually nobody notices.
Unsurprisingly, it doesn't go well with backward playback mode.
If you use --keep-open in forward playback mode, and seek past the end
of the file, it tries to seek to the very last frame. The demuxer will
seek to the last "keyframe" before the end (i.e. some frames to go in
most cases), and trying to hr-seek to the file duration often won't cut
it, so this requires some special code. The function at hand seeks
"close" to the end, and then stops hr-seek when the last frame us
encountered (simple enough and very effective).
In backward playback mode, start and end are reversed, and we need to
seek "close" to the start of the file instead. Simple enough to do, and
it works.
One problem is that command.c has some weird logic to make going beyond
the last chapter either end playback (--keep-open=no), or jump to the
last frame. Now this will jump to the first frame, which is weird, but
let's ignore this.
Another problem is that seeking before playback start position hits EOF
in backward playback mode, which is a demuxer bug, and has nothing to do
with this code. But it triggers this code, so seeking before the start
will show the "last" frame. (My description is a mess with directions.
Figure it out yourself.)
Obviously should seek back to the end of the file when it loops.
Also remove some minor code duplication around start times. This isn't
the correct solution by the way. Rather than hoping we know a reasonable
start/end time, this stuff should instruct the demuxer to seek to the
exact location. It'll work with 99% of all normal files, but add an
appropriate comment (that basically says the function is bullshit) to
get_start_time() anyway.
This changes the behavior of the --ab-loop-a/b options. In addition, it
makes it work with backward playback mode.
The most obvious change is that the both the A and B point need to be
set now before any looping happens. Unlike before, unset points don't
implicitly use the start or end of the file. I think the old behavior
was a feature that was explicitly added/wanted. Well, it's gone now.
This is because of 2 reasons:
1. I never liked this feature, and it always got in my way (as user).
2. It's inherently annoying with backward playback mode.
In backward playback mode, the user wants to set A/B in the wrong order.
The ab-loop command will first set A, then B, so if you use this command
during backward playback, A will be set to a higher timestamps than B.
If you switch back to forward playback mode, the loop would stop
working. I want the loop to just continue to work, and the chosen
solution conflicts with the removed feature.
The order issue above _could_ be fixed by also switching the AB-loop
user option values around on direction switch. But there are no other
instances of option changes magically affecting other options, and doing
this would probably lead to unexpected misery (dying from corner cases
and such).
Another solution is sorting the A/B points by timestamps after copying
them from the user options. Then A/B options set in backward mode will
work in forward mode. This is the chosen solution. If you sort the
points, you don't know anymore whether the unset point is supposed to
signify the end or the start of the file.
The AB-loop code is slightly better abstracted now, so it should be easy
to restore the removed feature. It would still require coming up with a
solution for backwards playback, though.
A minor change is that if one point is set and the other is unset, I'm
rendering both the chapter markers and the marker for the set point.
Why? I don't know. My test file had chapters, and I guess I decided this
looked better.
This commit also fixes some subtle and obvious issues that I already
forgot about when I wrote this commit message. It cleans up some minor
code duplication and nonsense too.
Regarding backward playback, the code uses an unsanitary mix of internal
("transformed") and user timestamps. So the play_dir variable appears
more than usual.
To mention one unfixed issue: if you set an AB-loop that is completely
past the end of the file, it will get stuck in an infinite seeking loop
once playback reaches the end of the file. Fixing this reliably seemed
annoying, so the fix is "just don't do this". It's not a hard freeze
anyway.
This code attempts to seek to the last frame by seeking close to the
end, and then decoding until the last frame has been reached. To do so
it sets hrseek_lastframe, which for video enables some logic to "catch"
this last frame, and completely ignores hrseek_pts. But audio still may
use hrseek_pts
I don't know if the original author (me) was thinking, if anything, when
setting this variable to 1e99, essentially a random, number. It's very
large, and a timestamp like this will never happen, so it does its job.
But it's random.
Use INFINITY instead. It will skip all audio samples in the audio code
correctly. This change doesn't fix anything, but it does get rid of the
random looking number.
The get_play_start_pts() function was supposed to return "rebased"
(relative to 0) timestamps. This was roundabout, because one of 2
callers just added the offset back, and the other caller actually
expected an absolute timestamp.
Change rel_time_to_abs() (whose return value get_play_start_pts()
returns without further changes) to return absolute times.
This should fix that absolute and relative times passed to --start and
--end were treated the same, which can't be right. It probably also
fixes --end if --rebase-start-time=no is used (which can't have been
correct either).
All in all I'm not sure why --rebase-start-time=no or absolute vs.
relative times in --start/--end even exist, when they were incorrectly
implemented for years.
Untested, because no sample file and I don't care. However, if anyone
cares, and I got it wrong, I hope it's simple to fix.
Has been deprecated for almost 3 years. Manpage didn't mention the
deprecation, but CLI and release notes did. It wouldn't be much effort
to keep this option working, but I just don't see the damn point.
--start/--end can specify chapters using special syntax, which is
equivalent.
We need to transform the timestamp returned by get_play_end_pts().
I considered making it return the transformed timestamp directly. There
are 4 callers; 2 need a transformed timestamps, 2 don't. So I guess it
doesn't matter.
This adds the stops using the same logic get_play_end_pts() and
handle_loop_file(). It did that before, it just looks slightly different
now. It also won't try to add MP_NOPTS_VALUE as stop value.
Just rearranging shit. Setting SEEK_HR for backstep seeks actually
doesn't have much meaning, but disables the weird audio snapping for
"keyframe" seeks, and I don't know it's late.
See manpage additions. This is a huge hack. You can bet there are shit
tons of bugs. It's literally forcing square pegs into round holes.
Hopefully, the manpage wall of text makes it clear enough that the whole
shit can easily crash and burn. (Although it shouldn't literally crash.
That would be a bug. It possibly _could_ start a fire by entering some
sort of endless loop, not a literal one, just something where it tries
to do work without making progress.)
(Some obvious bugs I simply ignored for this initial version, but
there's a number of potential bugs I can't even imagine. Normal playback
should remain completely unaffected, though.)
How this works is also described in the manpage. Basically, we demux in
reverse, then we decode in reverse, then we render in reverse.
The decoding part is the simplest: just reorder the decoder output. This
weirdly integrates with the timeline/ordered chapter code, which also
has special requirements on feeding the packets to the decoder in a
non-straightforward way (it doesn't conflict, although a bugmessmass
breaks correct slicing of segments, so EDL/ordered chapter playback is
broken in backward direction).
Backward demuxing is pretty involved. In theory, it could be much
easier: simply iterating the usual demuxer output backward. But this
just doesn't fit into our code, so there's a cthulhu nightmare of shit.
To be specific, each stream (audio, video) is reversed separately. At
least this means we can do backward playback within cached content (for
example, you could play backwards in a live stream; on that note, it
disables prefetching, which would lead to losing new live video, but
this could be avoided).
The fuckmess also meant that I didn't bother trying to support
subtitles. Subtitles are a problem because they're "sparse" streams.
They need to be "passively" demuxed: you don't try to read a subtitle
packet, you demux audio and video, and then look whether there was a
subtitle packet. This means to get subtitles for a time range, you need
to know that you demuxed video and audio over this range, which becomes
pretty messy when you demux audio and video backwards separately.
Backward display is the most weird (and potentially buggy) part. To
avoid that we need to touch a LOT of timing code, we negate all
timestamps. The basic idea is that due to the navigation, all
comparisons and subtractions of timestamps keep working, and you don't
need to touch every single of them to "reverse" them.
E.g.:
bool before = pts_a < pts_b;
would need to be:
bool before = forward
? pts_a < pts_b
: pts_a > pts_b;
or:
bool before = pts_a * dir < pts_b * dir;
or if you, as it's implemented now, just do this after decoding:
pts_a *= dir;
pts_b *= dir;
and then in the normal timing/renderer code:
bool before = pts_a < pts_b;
Consequently, we don't need many changes in the latter code. But some
assumptions inhererently true for forward playback may have been broken
anyway. What is mainly needed is fixing places where values are passed
between positive and negative "domains". For example, seeking and
timestamp user display always uses positive timestamps. The main mess is
that it's not obvious which domain a given variable should or does use.
Well, in my tests with a single file, it suddenly started to work when I
did this. I'm honestly surprised that it did, and that I didn't have to
change a single line in the timing code past decoder (just something
minor to make external/cached text subtitles display). I committed it
immediately while avoiding thinking about it. But there really likely
are subtle problems of all sorts.
As far as I'm aware, gstreamer also supports backward playback. When I
looked at this years ago, I couldn't find a way to actually try this,
and I didn't revisit it now. Back then I also read talk slides from the
person who implemented it, and I'm not sure if and which ideas I might
have taken from it. It's possible that the timestamp reversal is
inspired by it, but I didn't check. (I think it claimed that it could
avoid large changes by changing a sign?)
VapourSynth has some sort of reverse function, which provides a backward
view on a video. The function itself is trivial to implement, as
VapourSynth aims to provide random access to video by frame numbers (so
you just request decreasing frame numbers). From what I remember, it
wasn't exactly fluid, but it worked. It's implemented by creating an
index, and seeking to the target on demand, and a bunch of caching. mpv
could use it, but it would either require using VapourSynth as demuxer
and decoder for everything, or replacing the current file every time
something is supposed to be played backwards.
FFmpeg's libavfilter has reversal filters for audio and video. These
require buffering the entire media data of the file, and don't really
fit into mpv's architecture. It could be used by playing a libavfilter
graph that also demuxes, but that's like VapourSynth but worse.
This is a minor benign hack that reorders the MPV_FORMAT_NODE output.
The order of members is not supposed to matter, but it's how the OSD
renders them as raw output. Normally this isn't used, but
demuxer-cache-state is a "prominent" case. Moving the seek ranges to the
end avoids that the more important other fields are not cut off by going
out of the screen on the bottom.
Also output the seek ranges in reverse. The order doesn't matter either
(as declared by input.rst). Currently, the demuxer orders them by least
recent use. Reversing it makes the most recently used range (the current
range) show up on top.
In other words, this commit does basically nothing but fudge stuff in a
cosmetic way to make debugging easier for me, and you've wasted your
time reading this commit message and the diff. Good.
This will properly notify observed properties if the player hasn't
started actual playback yet, such as with --demuxer-cache-wait.
This also happens to cause the main loop more often, which triggers
MPV_EVENT_IDLE, and fixes the OSC display. (See previous commit
message.)
The OSC's (osc.lua) event handling is fundamentally broken. It waits for
MPV_EVENT_TICK to update the UI, and MPV_EVENT_TICK has become entirely
meaningless, except as a hack for the OSC. There are many situations
where the OSC doesn't properly update because the TICK event it expects
isn't sent.
Fix one of them: it doesn't update the cache state if the VO window is
forced and --demuxer-cache-wait is used. Make it so that the tick event
is sent even if playback initialization is taking time.
This is still slightly broken, because it works only if the mainloop is
actually run, which depends on random circumstances (such as moving the
mouse over the VO window). The next commit will add another such
circumstance which will make it appear to work, although it's still
conceptually broken. If we "fixed" it and strictly woke up the player
if the idle timer ran out, we'd send tick events all the time, even
if nothing is going on, which we don't want. Fucking shitshow.
This is just redundant and slightly annoying, at least for normal
command line usage. If there are multiple entries, still print it
(because you want to know where you are). Also still print it if the
player was redirected (because you want to know where you got redirected
to).
Remove the singly linked list hack, replace it with a slightly more
proper data structure. This probably gets rid of a few minor bugs along
the way, caused by the awkward nonsensical sharing/duplication of some
fields.
Another change (because I'm touching everything related to timeline
anyway) is that I'm removing the special semantics for parts[num_parts].
This is now strictly out of bounds, and instead of using the start time
of the next/beyond-last part, there is an end time field now.
Unfortunately, this also requires touching the code for cue and mkv
ordered chapters. From some superficial testing, they still seem to
mostly work.
One observable change is that the "no_chapters" header is per-stream
now, which is arguably more correct, and getting the old behavior would
require adding code to handle it as special-case, so just adjust
ytdl_hook.lua to the new behavior.
I noticed that some ytdl streams have a start time other than 0. There's
currently no mechanism inside of the EDL stuff that determines this
start time correctly, so it can happen that if the start time is high,
demux_timeline.c tries to clip off the entire video and audio, resulting
in failure of playback.
As a counter measure, use the no_clip header, which entirely disables
clipping against time ranges in demux_timeline.c. (It's basically a
hack.)
E.g. "mpv null:// --demuxer=rawvideo" will "hang" by waiting for video
EOF forever. It's not signalled correctly because of the last-frame
corner case, which attempts to wait until the current frame is finally
displayed (which is signalled by whether a new frame can be queued, see
commit 1a339fa09d for some details). If no frame was ever queued, the VO
is not configured, and vo_is_ready_for_frame() never returns true.
Fix this by using vo_has_frame(), which seems to be exactly the correct
thing we need.
Init fragments are not a necessity for DASH, but this code assumed so.
Maybe the check was to prevent worse. But using normal EDL here leads to
very shitty behavior where it tries to open hundreds or thousands of
fragments, each with its own demuxer and HTTP connection. (This behavior
is fine for normal uses of EDLs, but completely unacceptable when
emulating fragmented streaming protocols. I'm not sure why the normal
EDL code is needed here, but I think someone claimed some obscure sites
just need it.)
This happens in the same situation as the one described in the previous
commit.
Otherwise we'd just use the base URL as media URL, which would fail with
a 404 error.
Not sure if there's a deeper reason why the audio path was explicitly
different from the video one. But this actually works now for a video
that returned fragmented DASH audio with the default format selection.
(This affects streams on that well known site of a big evil Silicon
Valley company. Typically happens after live stream gets converted to a
normal video, though after some time passes, this fragmented version is
deleted, and replaced by a non-fragmented one. I've observed this
several times and this seems to be the "normal" behavior.)
This merges separate audio and video tracks into one virtual stream,
which helps the mpv caching layer. See previous EDL commit for details.
It's apparently active for most of evil Silicon Valley giant's streaming
videos.
Initial tests seem to work fine, except it happens pretty often that
playback goes into buffering immediately even when seeking within a
cached range, because there is not enough forward cache data yet to
fully restart playback. (Or something like this.)
The audio stream title used to be derived from track.format_note; this
commit stops doing so. It seemed pointless anyway. If really necessary,
it could be restored by adding new EDL headers.
Note that we explicitly don't do this with subtitle tracks. Subtitle
tracks still have a chance with on-demand loading or loading in the
background while video is already playing; merging them with EDL would
prevent this. Currently, subtitles are still added in a "blocking"
manner, but in theory this could be loosened. For example, the Lua API
already provides a way to run processes asynchronously, which could be
used to add subtitles during playback. EDL will probably be never
flexible enough to provide this. Also, subtitles are downloaded at
once, rather than streamed like audio and video.
Still missing: disabling EDL's pointless chapter generation, and
propagating download speed statistics through the EDL wrapper.
The ytdl wrapper can resolve web links to playlists. This playlist is
passed as big memory:// blob, and will contain further quite normal web
links. When playback of one of these playlist entries starts, ytdl is
called again and will resolve the web link to a media URL again.
This didn't work if playlist entries resolved to EDL URLs. Playback was
rejected with a "potentially unsafe URL from playlist" error. This was
completely weird and unexpected: using the playlist entry directly on
the command line worked fine, and there isn't a reason why it should be
different for a playlist entry (both are resolved by the ytdl wrapper
anyway). Also, if the only EDL URL was added via audio-add or sub-add,
the URL was accessed successfully.
The reason this happened is because the playlist entries were marked as
STREAM_SAFE_ONLY, and edl:// is not marked as "safe". Playlist entries
passed via command line directly are not marked, so resolving them to
EDL worked.
Fix this by making the ytdl hook set load-unsafe-playlists while the
playlist is parsed. (After the playlist is parsed, and before the first
playlist entry is played, file-local options are reset again.) Further,
extend the load-unsafe-playlists option so that the playlist entries are
not marked while the playlist is loaded.
Since playlist entries are already verified, this should change nothing
about the actual security situation.
There are now 2 locations which check load_unsafe_playlists. The old one
is a bit redundant now. In theory, the playlist loading code might not
be the only code which sets these flags, so keeping the old code is
somewhat justified (and in any case it doesn't hurt to keep it).
In general, the security concept sucks (and always did). I can for
example not answer the question whether you can "break" this mechanism
with various combinations of archives, EDL files, playlists files,
compromised sites, and so on. You probably can, and I'm fully aware that
it's probably possible, so don't blame me.
struct stream used to include the stream buffer, including peek buffer,
inline in the struct. It could not be resized, which means the maximum
peek size was set in stone. This meant demux_lavf.c could peek only so
much data.
Change it to use a dynamic buffer. Because it's possible, keep the
inline buffer for default buffer sizes (which are basically always used
outside of file opening). It's unknown whether it really helps with
anything. Probably not.
This is also the fallback plan in case we need something like the old
stream cache in order to deal with mp4 + unseekable http: the code can
now be easily changed to use any buffer size.
Instead of going through those weird DEMUXER_CTRLs, query this
information directly. I'm not sure which kind of brain damage made me
use CTRLs for these. Since there are no other DEMUXER_CTRLs that make
sense for the frontend, remove the remaining infrastructure for them
too.
The stream size return was the only thing that still required doing
STREAM_CTRLs from frontend through the demuxer layer. This can be done
much easier, so rip it out. Also rip out the now unused infrastructure
for STREAM_CTRLs via demuxer layer.
Apparently this was so that when playing a video file from a .rar file,
it would load external subtitles with the same name (instead of looking
for mpv's rar:// mangled URL). This was requested on github almost 5
years ago. Seems like a weird feature, and I don't care. Drop it,
because it complicates some in progress change.
The "program" property could switch between TS programs. It was rather
complex and rather obscure (even if you deal with TS captures, you
usually don't need it). If anyone actually needs it (did anyone ever
attempt to even use it?), it should be rewritten. The demuxer should
export a program list, and the frontend should handle the "cycling"
logic.
Linux analog TV support (via tv://) was excessively complex, and
whenever I attempted to use it (cameras or loopback devices), it didn't
work well, or would have required some major work to update it. It's
very much stuck in the analog past (my favorite are the frequency tables
in frequencies.c for analog TV channels which don't exist anymore).
Especially cameras and such work fine with libavdevice and better than
tv://, for example:
mpv av://v4l2:/dev/video0
(adding --profile=low-latency --untimed even makes it mostly realtime)
Adding a new input layer that targets such "modern" uses would be
acceptable, if anyone is interested in it. The old TV code is just too
focused on actual analog TV.
DVB is rather obscure, but has an active maintainer, so don't remove it.
However, the demux/stream ctrl layer must go, so remove controls for
channel switching. Most of these could be reimplemented by using the
normal method for option runtime changes.
This removes anything related to DVD/BD/CD that negatively affected the
core code. It includes trying to rewrite timestamps (since DVDs and
Blurays do not set packet stream timestamps to playback time, and can
even have resets mid-stream), export of chapters, stream languages,
export of title/track lists, and all that.
Only basic seeking is supported. It is very much possible that seeking
completely fails on some discs (on some parts of the timeline), because
timestamp rewriting was removed.
Note that I don't give a shit about optical media. If you want to watch
them, rip them. Keeping some bare support for DVD/BD is the most I'm
going to do to appease the type of lazy, obnoxious users who will care.
There are other players which are better at optical discs.
Semantics changes are the same as at 548ef078 .
Also, the previous C implementation returnd a string for the `stdout`
value, but stdout of the subprocess command is MPV_FORMAT_BYTE_ARRAY
which js previously didn't support, so support it too (at pushnode)
by returning it as a string - the same as the lua code does.
There were some cases where a js number (double) was blindly casted to
int or uint64, but that can be undefined behavior (out of range to int)
or wrong (negative to uint).
Now the code throws a js error if the value is out of range.
Additionally, commit ec625266 added these checks for the new hooks API,
but incorrectly tested int64 range rather than uint64. Fix this too.
Adds the negation missed in 8816e1117e
when moving from a positive-is-active to positive-is-idle variable.
This leads to proper updates to properties such as "eof-reached",
as well as fixes screensaver state updates.
Separately found and fixed by avih and wnoun.
Co-authored-by: wnoun <wnoun@outlook.com>
Manual changes done:
* Merged the interface-changes under the already master'd changes.
* Moved the hwdec-related option changes to video/decode/vd_lavc.c.
As stated in the original commit message, if the demuxer set the start
time to the first subtitle packet, the subtitles would be shifted
incorrectly. It appears that it is the case for external PGS subtitles.
This reverts commit 520fc74036.
Fixes#5485
Merge file-size/file-format and audio channel-count/format into one line
respectively. This fixes stats overflowing the screen in larger than
19:6 aspect ratios. In this case a problem was reported for ~21:9 which
should be common enough for us to "support" it.
Idle handlers used to not be executed when timers were active
Now they are executed:
* After all expired timers have been executed
* After all events have been processed (same as when there are no timers)
--record-file is nice, but only sometimes. If you watch some sort of
livestream which you want to record, it's actually much nicer not to
record what you're currently "seeing", but anything you're receiving.
The buffer is written to in `audio_config_to_str_buf` using `snprintf`
with a `%s` formatting of a 128-byte buffer. This can overflow the
target buffer of 80 causing a truncated output.
mpctx->current_track[0][STREAM_VIDEO] (and STREAM_AUDIO) are empty when
using --lavfi-complex. Moving the muxer stream hinting after audio/video chain
initialization and checking if the chains exist fixes encoding with --lavfi-complex.
Previously, the output audio/video streams did not get prepared and the encode
would fail due to unexpected stream addition.
The demuxer cache is the only cache now. Might need another change to
combat seeking failures in mp4 etc. The only bad thing is the loss of
cache-speed, which was sort of nice to have.
Quitting is slightly asynchronous, so the status line can be updated
again. Normally, that's fine, but if quitting comes with a message (such
as with quit_watch_later), it will print the status line again after the
message, which looks annoying. So flush and clear the status message if
it's updated during quitting.
When seeking near the end of the file and the next file loads, seeking
continues on the next file at the same position and then immediately
the file after that. This patch stops slider seeking when a new file is
loaded, which is the standard behavior of many other players.
The player fully restarts playback when the edition or disk title is
changed. Before this, the player tried to reinitialized playback
partially. For example, it did not print a new "Playing: <file>"
message, and did not send playback end to libmpv users (scripts or
applications).
This playback restart code was a bit messy and could have unforeseen
interactions with various state. There have been bugs before. Since it's
a mostly cosmetic thing for an obscure feature, just change it to a full
restart. This works well, though since it may have consequences for
scripts or client API users, mention it in interface-changes.rst.
When changing video filters during initialization, there was a small
time window where video was initialized, but playback restart was not
complete yet. In this time window, playback_pts is not set. But since
issue_refresh_seek() was using this, it could lead to no refresh being
done _if_ the "video" had only 1 frame (such as cover art).
Fix this by using get_current_time() instead, which is the current time
with corner cases such as ongoing loading or seeks taken into account.
See also the previous commit. Without that, get_current_time() could
return NOPTS during init.
Fixes#5831.
This is working towards a change intended in the future: nothing should
write to the option struct directly, but use functions that raise proper
notifications. Until this is complete it will take a while, and this
commit does not change all cases of direct access, just some simple
ones.
In all of these 3 changes, the actual write access is done by the
generic property-option bridge.
This was always a legacy thing. Remove it by applying an orgy of
mp_get_config_group() calls, and sometimes m_config_cache_alloc() or
mp_read_option_raw().
win32 changes untested.
The --hwdec* options are a good fit for the vd_lavc local option
struct. This annoyingly requires manual prefixing of most of these
options with --vd-lavc (could be avoided by using more sub-struct
craziness, but let's not).
The path functions need to access the option that forces non-default
config directories. Just add it as a field to mpv_global - it seems
justified. The accessed options were always enforced as immutable after
init, so there's not much of a change.
Until now, stopping playback aborted the demuxer and I/O layer violently
by signaling mp_cancel (bound to libavformat's AVIOInterruptCB
mechanism). Change it to try closing them gracefully.
The main purpose is to silence those libavformat errors that happen when
you request termination. Most of libavformat barely cares about the
termination mechanism (AVIOInterruptCB), and essentially it's like the
network connection is abruptly severed, or file I/O suddenly returns I/O
errors. There were issues with dumb TLS warnings, parsers complaining
about incomplete data, and some special protocols that require server
communication to gracefully disconnect.
We still want to abort it forcefully if it refuses to terminate on its
own, so a timeout is required. Users can set the timeout to 0, which
should give them the old behavior.
This also removes the old mechanism that treats certain commands (like
"quit") specially, and tries to terminate the demuxers even if the core
is currently frozen. This is for situations where the core synchronized
to the demuxer or stream layer while network is unresponsive. This in
turn can only happen due to the "program" or "cache-size" properties in
the current code (see one of the previous commits). Also, the old
mechanism doesn't fit particularly well with the new one. We wouldn't
want to abort playback immediately on a "quit" command - the new code is
all about giving it a chance to end it gracefully. We'd need some sort
of watchdog thread or something equally complicated to handle this. So
just remove it.
The change in osd.c is to prevent that it clears the status line while
waiting for termination. The normal status line code doesn't output
anything useful at this point, and the code path taken clears it, both
of which is an annoying behavior change, so just let it show the old
one.
Before this, mpctx->playing was often used to determine whether certain
new state could be added to the playback state. In particular this
affected external files (which added tracks and demuxers). The variable
was checked to prevent that they were added before the corresponding
uninit code. We want to make a small part of uninit asynchronous, but
mpctx->playing needs to stay in the place where it is. It can't be used
for this purpose anymore.
Use mpctx->stop_play instead. Make it never have the value 0 outside of
loading/playback. On unloading, it obviously has to be non-0.
Change some other code in playloop.c to use this, because it seems
slightly more correct. But mostly this is preparation for the following
commit.
Alway give each demuxer its own mp_cancel instance. This makes
management of the mp_cancel things much easier. Also, instead of having
add/remove functions for mp_cancel slaves, replace them with a simpler
to use set_parent function. Remove cancel_and_free_demuxer(), which had
mpctx as parameter only to check an assumption. With this commit,
demuxers have their own mp_cancel, so add demux_cancel_and_free() which
makes use of it.
Them being separate is just dumb. Replace them with a single
demux_free() function, and free its stream by default. Not freeing the
stream is only needed in 1 special case (demux_disc.c), use a special
flag to not free the stream in this case.
The player fully restarts playback when the edition or disk title is
changed. Before this, the player tried to reinitialized playback
partially. For example, it did not print a new "Playing: <file>"
message, and did not send playback end to libmpv users (scripts or
applications).
This playback restart code was a bit messy and could have unforeseen
interactions with various state. There have been bugs before. Since it's
a mostly cosmetic thing for an obscure feature, just change it to a full
restart. This works well, though since it may have consequences for
scripts or client API users, mention it in interface-changes.rst.
The properties/commands touched in this commit are all for obscure
special inputs (BD/DVD/DVB/TV), and they all block on the demuxer/stream
layer. For network streams, this blocking is very unwelcome. They will
affect playback and probably introduce pauses and frame drops. The
player can even freeze fully, and the logic that tries to make playback
abortable even if frozen complicates the player.
Since the mentioned accesses are not needed for network streams, but
they will block on network streams even though they're going to fail,
add a flag that coarsely enables/disables these accesses. Essentially it
establishes a whitelist of demuxers/streams which support them.
In theory you could to access BD/DVD images over network (or add such
support, I don't think it's a thing in mpv). In these cases these
controls still can block and could even "freeze" the player completely.
Writing to the "program" and "cache-size" properties still can block
even for network streams. Just don't use them if you don't want freezes.
Don't allow it to freeze everything when loading a playlist from network
(although you definitely shouldn't do that, but whatever).
This also affects the really obscure --ordered-chapters-files option.
The --playlist option on the other hand has no choice but to freeze the
shit, because there's no concept of aborting the player during command
line parsing.
Until now, they could be aborted only by ending playback, and calling
mpv_abort_async_command didn't do anything.
This requires furthering the mess how playback abort is done. The main
reason why mp_cancel exists at all is to avoid that a "frozen" demuxer
(blocked on network I/O or whatever) cannot freeze the core. The core
should always get its way. Previously, there was a single mp_cancel
handle, that could be signaled, and all demuxers would unfreeze. With
external files, we might want to abort loading of a certain external
file, which automatically means they need a separate mp_cancel. So give
every demuxer its own mp_cancel, and "slave" it to whatever parent
mp_cancel handles aborting.
Since the mpv demuxer API conflates creating the demuxer and reading the
file headers, mp_cancel strictly need to be created before the demuxer
is created (or we couldn't abort loading). Although we give every
demuxer its own mp_cancel (as "enforced" by cancel_and_free_demuxer),
it's still rather messy to create/destroy it along with the demuxer.
It seems a bit inappropriate to have dumped this into stream.c, even if
it's roughly speaking its main user. At least it made its way somewhat
unfortunately to other components not related to the stream or demuxer
layer at all.
I'm too greedy to give this weird helper its own file, so dump it into
thread_tools.c.
Probably a somewhat pointless change.
Before this change, only 1 command or so had named arguments. There is
no reason why other commands can't have them, except that it's a bit of
work to add them.
Commands with variable number of arguments are inherently incompatible
to named arguments, such as the "run" command. They still have dummy
names, but obviously you can't assign multiple values to a single named
argument (unless the argument has an array type, which would be
something different). For now, disallow using named argument APIs with
these commands. This might change later.
2 commands are adjusted to not need a separate default value by changing
flag constants. (The numeric values are C only and can't be set by
users.)
Make the command syntax in the manpage more consistent. Now none of the
allowed choice/flag names are in the command header, and all arguments
are shown with their proper name and quoted with <...>.
Some places in the manpage and the client.h doxygen are updated to
reflect that most commands support named arguments. In addition, try to
improve the documentation of the syntax and need for escaping etc. as
well.
(Or actually most uses of the word "argument" should be "parameter".)
When changing video filters during initialization, there was a small
time window where video was initialized, but playback restart was not
complete yet. In this time window, playback_pts is not set. But since
issue_refresh_seek() was using this, it could lead to no refresh being
done _if_ the "video" had only 1 frame (such as cover art).
Fix this by using get_current_time() instead, which is the current time
with corner cases such as ongoing loading or seeks taken into account.
See also the previous commit. Without that, get_current_time() could
return NOPTS during init.
Fixes#5831.
This is nonsense. Didn't matter in most situations, because seeking
itself set this after it was cleared. But some callers don't do this,
see e.g. commit ed73ba8964. There is no need to clear it at all, and
it causes issues with the next commit. It only needs to be reset on
loading.
Also move the initialization on loading up, which doesn't change
behavior, but makes the intention clearer.
This affects async commands started by client API, commands with async
capability run in a sync way by client API (think mpv_command_node()
with "subprocess"), and detached async work.
Since scripts might want to do some cleanup work (that might involve
launching processes, don't ask), we don't unconditionally kill
everything on exit, but apply an arbitrary timeout of 2 seconds until
async commands are aborted.
Many asynchronous commands are potentially long running operations, such
as loading something from network or running a foreign process.
Obviously it shouldn't just be possible for them to freeze the player if
they don't terminate as expected. Also, there will be situations where
you want to explicitly stop some of those operations explicitly. So add
an infrastructure for this.
Commands have to support this explicitly. The next commit uses this to
actually add support to a command.
If a struct as large as MPContext contains a field named "lock", it
creates the impression that it is the primary lock for MPContext. This
is wrong, the lock just protects a single field.
The "run" command is old. I'm not sure why the separate Lua
implementation was added. But maybe it as because the "run" command used
to be limited to a small number of arguments. This limit has been
removed a while ago. In any case, the old implementation is not needed
anymore.
We keep mp.subprocess() with roughly the same semantics for
compatibility with scripts (including the internal ytdl script).
Seems to work with rhe ytdl wrapper. Not tested further.
This supports named arguments. It benefits from the infrastructure of
async commands.
The plan is to reimplement Lua's utils.subprocess() on top of it.
Basically reimplement the async behavior on top of the async command
code. With this, all screenshot commands are async, and the "async"
prefix basically does nothing. The prefix now behaves exactly like with
other commands that use spawn_thread.
This also means using the prefix in the preset input.conf is pointless
(without effect) and misleading, so remove that.
The each_frame mode was actually particularly painful in making this
change, since the player wants to block for it when writing a
screenshot, and generally doesn't fit into the new infrastructure. It
was still relatively easy to reimplement by copying the original command
and then repeating it on each frame. The waiting is reentrant now, so
move the call in video.c to a "safer" spot.
One way to observe how the new semantics interact with everything is
using the mpv repl script and sending a screenshot command through it.
Without async flag, the script will freeze while writing the screenshot
(while playback continues), while with async flag it continues.
Commands are not a monolithic giant switch() statement anymore, but
individual functions. There's no reason to have the command handlers
themselves in command.c, with a weird under-defined API in between.
(In the future, I'd like to split up command.c further, and when I do
that, scrrenshot.c will probably gets its own mp_cmd_def[] array, and
define the commands locally instead of exporting the raw handlers.)
Basically, the ytdl_hook script will not terminate the script, even if
you change to a new playlist entry. This happens because ytdl_hook keeps
the player core in an early loading stage, and the forceful playback
abort is done only in the ermination code.
This does not handle the "stop" and "quit" commands, which can still
take longer than expected, but on the other hand have some weird special
handling (see below). I'm not doing this out of laziness. Playback
stopping will have to be somewhat redone anyway. Basically we want to
give everything a chance to terminate, and if it doesn't work, we want
to stop loading or playback forcefully after a small timeout. We also
want to remove the mess with input.c's special handling of "quit" and
some other commands (see abort_playback_cb stuff).
It seems the ytdl script like to continue loading external tracks even
if loading was aborted. Trying to do so will still quickly fail, but not
without a load of log noise. So check and error out early.
Pretty trivial, since commands can be async now, and the common code
even provides convenience like running commands on a worker thread.
The only ugly thing is that mp_add_external_file() needs an extra flag
for locking. This is because there's still some code which calls this
synchronously from the main thread, and unlocking the core makes no
sense there.
This enables two types of command behavior:
1. Plain async behavior, like "loadfile" not completing until the file
is fully loaded.
2. Running parts of the command on worker threads, e.g. for I/O, such as
"sub-add" doing network accesses on a thread while the core
continues.
Both have no implementation yet, and most new code is actually inactive.
The plan is to implement a number of useful cases in the following
commits.
The most tricky part is handling internal keybindings (input.conf) and
the multi-command feature (concatenating commands with ";"). It requires
a bunch of roundabout code to make it do the expected thing in
combination with async commands.
There is the question how commands should be handled that come in at a
higher rate than what can be handled by the core. Currently, it will
simply queue up input.conf commands as long as memory lasts. The client
API is limited by the size of the reply queue per client. For commands
which require a worker thread, the thread pool is limited to 30 threads,
and then will queue up work in memory. The number is completely
arbitrary.
The existing thread pool code is the most primitive thread pool
possible. That's fine, but one annoying thing was that it used a static
number of threads. Make it dynamic, so we don't need to "waste" idle
threads.
This tries to add threads as needed. If threads are idle for some time,
destroy them again until a minimum number of threads is reached.
Also change the license to ISC.
This has some tricky interactions. In particular, it requires the core
to be locked due to reading outstanding_async, which is documented on
the only caller only. It's probably better to merge it with its only
caller.
The new code should be strictly equivalent, other than the fact that it
doesn't temporarily unlock+lock when entering the loop for the first
time (which doesn't matter here).
Fixes several issues playing back mpegts with video streams marked
as having "still images". For example, see this video which has
frames only every 6s: https://s3.amazonaws.com/tmm1/music-choice.ts
Changes include:
- start playback right away, without waiting for first video frame
- do not consider the sparse video stream in demuxer underrun detection
- do not require multiple video frames for the VO
- use audio as the master stream for demuxer metadata events
- use audio stream for playback time
Signed-off-by: Aman Gupta <aman@tmm1.net>
Fixes `--ytdl-format="dash-fastly_skyfire-video-363357330+dash-fastly_skyfire_sep-audio-363357330" https://vimeo.com/108650530`
This happened because the video track also had audio available and after
adding it expecting an audio-only track, there were no more tracks with video.
Could make it behave differently (and leak memory) in certain cases.
Basically, m_option_parse() randomly returns 0 or 1, but most time 1,
with the difference due to legacy reasons that don't matter anymore.
The "if (prop.name)" check is redundant, because an assert above it
implies that it never can be NULL.
Deduplicate some code for initializing the "prop" variable.
This gets rid of run_command() and its big switch statement, which was
an idiotically big function of almost 1000 lines.
The switch is replaced with a callback per command, and each command is
now implemented in its own function. Command IDs are not needed anymore,
so the mp_command_type enum disappears.
There should be no functional changes, but since this refactors 64
commands, regressions are possible.
The handler() parameter is void*, because in theory the input code is
supposed to be independent of the player core code. For example, you
should be able to reuse the command parser code for some other part of
mpv. In practice, the variable containing command list is defined in the
player core anyway, so you could say this doesn't work. But I'm still
trying to hold onto this idea, so I went with void*.
The plan is to remove the command ID enum. This will happen by replacing
the big switch statement in command.c with dispatching to per-command
callbacks. As preparation, remove uses of the command IDs outside of the
actual dispatching mechanism.
Also remove some instances of checking cmd->def for NULL. We now require
this always to be set.
Until recently, ao_lavc and vo_lavc started encoding whenever the core
happened to send them data. Since audio and video are not initialized at
the same time, and the muxer was not necessarily opened when the first
encoder started to produce data, the resulting packets were put into a
queue. As soon as the muxer was opened, the queue was flushed.
Change this to make the core wait with sending data until all encoders
are initialized. This has the advantage that we don't need to queue up
the packets.
The video timing code could just decide that EOF was reached before it
was displayed. This is not really a problem for normal playback (if you
use something like --keep-open it'd show the last frame anyway,
otherwise it'd at best flash it on screen before destroying the window).
But in encode mode, it really matters, and makes the difference between
having one frame more or less in the output file.
Fix this by waiting for the VO before starting the real EOF.
vo_is_ready_for_frame() is normally used to determine when the VO frame
queue has enough space to send a new frame. Since the VO frame queue is
currently at most 1 frame, it being signaled means the remaining frame
was consumed and thus sent to the VO driver. If it returns false, it
will wake up the playloop as soon as the state changes.
I also considered using vo_still_displaying(), but it's not reliable,
because it checks the realtime of the frame end display time.
Instead of using an internal counter to keep track of the value that was
set last, attempt to find the current value of the property/option in
the value list, and then set the next value in the list.
There are some potential problems. If a property refuses to accept a
specific value, the cycle-values command will fail, and start from the
same position again. It can't know that it's supposed to skip the next
value. The same can happen to properties which behave "strangely", such
as the "aspect" property, which will return the current aspect if you
write "-1" to it. As a consequence, cycle-values can appear to get
"stuck".
I still think the new behavior is what users expect more, and which is
generally more useful. We won't restore the ability to get the old
behavior, unless we decide to revert this commit entirely.
Fixes#5772, and hopefully other complaints.
If playback has not been initialized yet (decoders not initialized
etc.), or if in idle mode, let the track properties cycle through "no"
and "auto". This should be slightly more helpful than making it simply
exit.
Depending on the stage of loading, more could be done. For example, if
youtube-dl loads additional subtitle files, it can happen that these get
added before the main file, and this could be cycled through to an
extent. This is probably too clever, and also sort of dangerous
(unintended interactions with messy in-loading state), so don't do it.
The main change is that we wait with opening the muxer ("writing
headers") until we have data from all streams. This fixes race
conditions at init due to broken assumptions in the old code.
This also changes a lot of other stuff. I found and fixed a few API
violations (often things for which better mechanisms were invented, and
the old ones are not valid anymore). I try to get away from the public
mutex and shared fields in encode_lavc_context. For now it's still
needed for some timestamp-related fields, but most are gone. It also
removes some bad code duplication between audio and video paths.
1. I want to get away from mp_image_params (maybe).
2. For encoding mode, it's convenient to get the nominal_fps, which is
a mp_image field, and not in mp_image_params.
Also rename stereo3d to stereo_in. The only real change is that the
vo_gpu OSD code now uses the actual stereo 3D mode, instead of the
--video-steroe-mode value. (Why does this vo_gpu code even exist?)
DR (letting the decoder allocate texture memory) requires running the
allocation on the render thread. This is rather hard with the render
API, because the user controls this thread and when it's entered. It was
not possible until now.
This commit adds a bunch of infrastructure to make this possible. We add
a new optional mode (MPV_RENDER_PARAM_ADVANCED_CONTROL) which basically
lets the user's render thread and libmpv agree how this should be done.
Misuse would lead to deadlocks. To make this less likely, strictly
document thread safety/locking issues. In particular, document which
libmpv functions can be called without issues. (The rest has to be
assumed unsafe.)
The worst issue is destruction of the render context while video is
still active. To avoid certain unintended recursive locks (i.e.
deadlocks, unless we'd make the locks recursive), make the update
callback lock separate. Make "killing" the video chain asynchronous, so
we can do extra work while video is being destroyed.
Because losing wakeups is a big deal, setting the update callback now
triggers a wakeup. (It would have been better if the wakeup callback
were a parameter to mpv_render_context_create(), but too late.)
This commit does not add DR yet; the following commit does this.
Fundamentally, scripts are loaded asynchronously, but as a feature,
there was code to wait until a script is loaded (for a certain arbitrary
definition of "loaded"). This was done in scripting.c with the
wait_loaded() function.
This called mp_idle(), and since there are commands to load/unload
scripts, it meant the player core loop could be entered recursively. I
think this is a major complication and has some problems. For example,
if you had a script that does 'os.execute("sleep inf")', then every time
you ran a command to load an instance of the script would add a new
stack frame of mp_idle(). This would lead to some sort of reentrancy
horror that is hard to debug. Also misc/dispatch.c contains a somewhat
tricky mess to support such recursive invocations. There were also some
bugs due to this and due to unforeseen interactions with other messes.
This scripting stuff was the only thing making use of that reentrancy,
and future commands that have "logical" waiting for something should be
implemented differently. So get rid of it.
Change the code to wait only in the player initialization phase: the
only place where it really has to wait is before playback is started,
because scripts might want to set options or hooks that interact with
playback initialization. Unloading of builtin scripts (can happen with
e.g. "set osc no") is left asynchronous; the unloading wasn't too robust
anyway, and this change won't make a difference if someone is trying to
break it intentionally. Note that this is not in mp_initialize(),
because mpv_initialize() uses this by locking the core, which would have
the same problem.
In the future, commands which logically wait should use different
mechanisms. Originally I thought the current approach (that is removed
with this commit) should be used, but it's too much of a mess and can't
even be used in some cases. Examples are:
- "loadfile" should be made blocking (needs to run the normal player
code and manually unblock the thread issuing the command)
- "add-sub" should not freeze the player until the URL is opened (needs
to run opening on a separate thread)
Possibly the current scripting behavior could be restored once new
mechanisms exist, and if it turns out that anyone needs it.
With this commit there should be no further instances of recursive
playloop invocations (other than the case in the following commit),
since all mp_idle()/mp_wait_events() calls are done strictly from the
main thread (and not commands/properties or libmpv client API that
"lock" the main thread).
ffmpeg marks audio tracks which are not meant to be played standalone
as DEPENDENT. these are typically used in DVB broadcasts for audio
descriptions, and are meant to be mixed into the main audio track during
playback.
This was slightly broken: since mp_initialize() did not necessarily
interrupt core_thread() (which is waiting for initialization), it did
not enter mp_play_files(), which would have sent an IDLE event.
I suppose that in some cases (like with mpv-android), the initial IDLE
event was never actually sent, because the first wakeup of the core
thread happens with the "loadfile" command, which will disallow the core
thread an IDLE event.
Although this was never observed to be happening, it seems definitely
possible: we first tell the main thread to exit, and then we ask the
main thread to do some work for us (with mp_dispatch_run()). Obviously
this is racy, and the main thread could exit without doing this, which
would block mp_dispatch_run() forever.
Fix this by changing the order of operation, so that it makes sense.
We could also just store the pthread_t of the main thread in some
variable, but the fact that pthread_create() might set the pthread_t
argument _after_ starting the thread makes this a bit messy (at least it
doesn't seem to be guaranteed on a superficial look at the manpage).
Until recently, the AO was reinitialized strictly only on decoder format
changes. But the commit for simplifying audio format negotiation removed
this. Now the AO is recreated for any format change.
This is sort of annoying if you change playback speed. The
insertion/removal of af_scaletempo can change the sample format. For
example, the acompressor filter will convert output to double, so
toggling scaletempo will force the format back to float. This recreates
the AO under the --gapless-audio=weak default. This likely affects a lot
of other filters too.
Work this around by allowing sample format changes, and keeping the
current AO format in these cases. This is probably not a big problem.
Most audio APIs force the output format to float anyway.
This means you actually have to worry about what the default gapless
mode does to your audio. If you start with a file that uses 8 bit per
sample, and then continue playing a 24 bit FLAC, it will be converted
down to 8 bit per sample. (Assuming they are played in a way that uses
the gapless logic.)
When dump's argument is an array, it was displaying <VISITED> for all
the array's object elements (objects, arrays, etc), regardless if they're
actually visited or not.
The reason is that we try to stringify twice: once normally which may
throw (on cycles), and a second time while excluding visited items which
is indicated by binding the replacer to an empty array - in which we hold
the visited items, where the replacer tests if its 'this' is an array or
not and acts accordingly.
However, its "this" may also be an array even if we don't bind it to one,
because its "normal" this is the main stringified object, so the test of
Array.isArray(this) is true when the top object is an array, and the object
items are indeed are in it - so the replacer considers them visited.
Fix by binding to null on the first attempt such that "this" is an array
only when we want it to test for visited items and not when the argument
itself is an array.
Due to earlier misinterpretation of the Lua docs as if mp.register_idle
registers a one-shot callback, the JS docs suggested to use setTimeout.
But the behavior and Lua docs are such that it's a repeating callback
which fires just before the script thread goes to sleep.
Implement it for JS too.
There was a "generic" function to run a hook and to wait for its
completion, yet there were two duplicated functions doing the same
anyway. Replace them with a single function.
They differed in how stop_play was handled, but it was broken anyway.
stop_play is set when playback is stopped due to quitting or changing
the playlist entry - but we still can't stop hook processing, because
that would mean asynchronously doing something else while the user hook
code is still busy and might still have the expectation that running the
hook stops everything else. So not waiting until the hook ends properly
is against the whole hook idea. That this was done inconsistently is
even worse. (Though it could be argued that when quitting the player,
everything should just be stopped violently. But I still think that's
up to the hook handler.)
process_hooks() does not return anything, since hook processing doesn't
really have a result (it's all about blocking and letting some other
code synchronously do something). Just let the caller check whether
loading was aborted in the meantime.
Also change the potentially misleading name of mp_hook_run().
As it turns out, there are multiple libmpv users who saw a need to
use the hook API. The API is kind of shitty and was never meant to be
actually public (it was mostly a hack for the ytdl script).
Introduce a proper API and deprecate the old one. The old one will
probably continue to work for a few releases, but will be removed
eventually.
There are some slight changes to the old API, but if a user followed
the manual properly, it won't break.
Mostly untested. Appears to work with ytdl_hook.
Move all of this stuff to a common function. This makes the error
messages less specific, but I don't think anyone will miss it.
The OSD flag handling is annoying, but it's nothing that should be
changed with this commit.
I think this will help with reducing code duplication (see following
commit). The error messages loses the multiplication factor, but the
error message will be replaced by a generic one in the following commit
anyway.
Hardware decoding things often need access to additional handles from
the windowing system, such as the X11 or Wayland display when using
vaapi. The opengl-cb had nothing dedicated for this, and used the weird
GL_MP_MPGetNativeDisplay GL extension (which was mpv specific and not
officially registered with OpenGL).
This was awkward, and a pain due to having to emulate GL context
behavior (like needing a TLS variable to store context for the pseudo GL
extension function). In addition (and not inherently due to this), we
could pass only one resource from mpv builtin context backends to
hwdecs. It was also all GL specific.
Replace this with a newer mechanism. It works for all RA backends, not
just GL. the API user can explicitly pass the objects at init time via
mpv_render_context_create(). Multiple resources are naturally possible.
The API uses MPV_RENDER_PARAM_* defines, but internally we use strings.
This is done for 2 reasons: 1. trying to leave libmpv and internal
mechanisms decoupled, 2. not having to add public API for some of the
internal resource types (especially D3D/GL interop stuff).
To remain sane, drop support for obscure half-working opengl-cb things,
like the DRM interop (was missing necessary things), the RPI window
thing (nobody used it), and obscure D3D interop things (not needed with
ANGLE, others were undocumented). In order not to break ABI and the C
API, we don't remove the associated structs from opengl_cb.h.
The parts which are still needed (in particular DRM interop) needs to be
ported to the render API.
Previously, section titles (File/Video/Audio) were printed as suffix of
a property that was assumed to always exist. However, with e.g.
lavi-complex this is not the case, therfore, print them without being
dependent on a property.
Switch from audio|video to audio|video-out-params properties as per
recommendation in #5670. These properties are tables and include
information explicitly queried later, so switch to using these tables
and reduce the amount of queried properties.
Fixes#5670
There is some sort-of awkwardness here, because option access needs to
happen in a synchronized manner, and the framedrop flag is not in the VO
option struct. Remove the mp_read_option_raw() call and the awkward
change notification via VO_EVENT_WIN_STATE from command.c, and pass it
through as new vo_frame flag.
Removes the awkward notification through VO_EVENT_WIN_STATE.
Unfortunately, some awkwardness remains in mp_property_display_fps(),
because the property has conflicting semantics with the option.
Before this change, mpv_wait_event() could inconsistently return
multiple MPV_EVENT_SHUTDOWN events to a single mpv_handle, up to the
point of spamming the event queue under certain circumstances. Change
this and just send it exactly once to each mpv_handle.
Some client API users might have weird requirements about destroying
their state asynchronously (and not reacting immediately to the SHUTDOWN
event). This change will help a bit to make this less weird and
surprising.
This changes how mpv_terminate_destroy() and mpv_detach_destroy()
behave. The doxygen in client.h tries to point out the differences. The
goal is to make this more useful to the API user (making it behave like
refcounting).
This will be refined in follow up commits.
Initialization is unfortunately closely tied to termination, so that
changes as well. This also removes earlier hacks that make sure that
some parts of FFmpeg initialization are run in the playback thread
(instead of the user's thread). This does not matter with standard
FFmpeg, and I have no reason to care about this anymore.
The intention is to reduce annoying differences between mpv CLI and
libmpv, and there's no reason to have the locale check only in libmpv
(although it doesn't help with any real issues either).
this API was introduced in c5e4538 solely for the use with cocoa-cb and
was not public. with the port to the new API in 760d471 it is now unused
and can safely be removed.
After switching, the playback state was not reset, which could leave it
in a strange, pause like state, that could be fixed by e.g. seeking.
This seems to be an older regression - it's even in 0.27.
Sometimes, playback needs to be fully uninitialized and reinitialized
without "officially" closing and reopening the playlist entry. This
happens with PT_RELOAD_FILE, which is triggered by edition switching and
also DVD/BD title switching. (Not really sure why it goes through so
much pain for such obscure cases. All it gains is not resetting "local"
options, and not signaling a reload to the client API. Whatever.)
The recent filter change freed filter_root too early without recreating
it, so it crashed on edition switching.
Fixes#5587.
If you used --aufio-file=file.mkv, and file.mkv included a video track
marked as default, then the logic in select_default_track() would pick
the video track from file.mkv. This is 100% broken, so fix it.
The playback start logic explicitly waits until the first frame has been
displayed. Usually this will introduce a wait of 1 vsync. For normal
playback this doesn't matter, but with respect to low latency needs,
this only leads to additional data getting queued up in the demuxer or
network buffers.
Another thing is that the timing logic decodes 1 frame ahead (= 1 frame
extra latency) to determine the exact duration of a frame.
To be fair, there doesn't really seem to be a hard reason why this is
needed. With the current code, enabling the option does lead to A/V
desync sometimes (if the demuxer FPS is too inaccurate), and also frame
drops at playback start in some situations. But this all seems to be
avoidable, if the timing logic were to be rewritten completely, which
should probably happen in the future. Thus the new option comes with the
warning that it can be removed any time. This is also why the option has
"hack" in the name.
The purpose of the new API is to make it useable with other APIs than
OpenGL, especially D3D11 and vulkan. In theory it's now possible to
support other vo_gpu backends, as well as backends that don't use the
vo_gpu code at all.
This also aims to get rid of the dumb mpv_get_sub_api() function. The
life cycle of the new mpv_render_context is a bit different from
mpv_opengl_cb_context, and you explicitly create/destroy the new
context, instead of calling init/uninit on an object returned by
mpv_get_sub_api().
In other to make the render API generic, it's annoyingly EGL style, and
requires you to pass in API-specific objects to generic functions. This
is to avoid explicit objects like the internal ra API has, because that
sounds more complicated and annoying for an API that's supposed to never
change.
The opengl_cb API will continue to exist for a bit longer, but
internally there are already a few tradeoffs, like reduced
thread-safety.
Mostly untested. Seems to work fine with mpc-qt.
Just bail out immediately (and disable audio) if format probing has no
result, instead of doing nothing and then apparently freezing.
This can happen with bogus filters, cases where the first audio frame is
essentially dropped by filters (can happen with large resampling
factors), and if the audio track contains no packets at all, or all
packets fail to decode.
This fixes playback stalls on some mediacodec hardware decoders,
which expect that frame buffers will be rendered and returned back
to the decoder as soon as possible.
Specifically, the issue was observed on an NVidia SHIELD Android TV,
only when playing an H264 sample which switched between interlaced
and non-interlaced frames. On an interlacing change, the decoder
expects all outstanding frames would be returned to it before it
would emit any new frames. Since a single extra frame always remained
buffered by mpv, playback would stall. After this commit, no extra
frames are buffered by mpv when using vo_mediacodec_embed.
Usable for uniquely identifying mpv instances from
subprocesses, controlling mpv with AppleScript, ...
Adds a new mp_getpid() wrapper for cross-platform reasons.
The recent changes to player/audio.c moved PTS jump detection to after
audio filtering. This was mostly done for convenience, because dataflow
between decoder and filters was made "automatic", and jump detection
would have to be done as filter. Now move it back to after decoders,
again out of convenience. The future direction is to make the dataflow
between filters and AO automatic, so this is a bit in the way. Another
reason is that speed changes tend to cause jumps - these are legitimate,
but get annoying quickly.
this is meant to replace the old and not properly working vo_gpu/opengl
cocoa backend in the future. the problems are various shortcomings of
Apple's opengl implementation and buggy behaviour in certain
circumstances that couldn't be properly worked around. there are also
certain regressions on newer macOS versions from 10.11 onwards.
- awful opengl performance with a none layer backed context
- huge amount of dropped frames with an early context flush
- flickering of system elements like the dock or volume indicator
- double buffering not properly working with a none layer backed context
- bad performance in fullscreen because of system optimisations
all the problems were caused by using a normal opengl context, that
seems somewhat abandoned by apple, and are fixed by using a layer backed
opengl context instead. problems that couldn't be fixed could be
properly worked around.
this has all features our old backend has sans the wid embedding,
the possibility to disable the automatic GPU switching and taking
screenshots of the window content. the first was deemed unnecessary by
me for now, since i just use the libmpv API that others can use anyway.
second is technically not possible atm because we have to pre-allocate
our opengl context at a time the config isn't read yet, so we can't get
the needed property. third one is a bit tricky because of deadlocking
and it needed to be in sync, hopefully i can work around that in the
future.
this also has at least one additional feature or eye-candy. a properly
working fullscreen animation with the native fs. also since this is a
direct port of the old backend of the parts that could be used, though
with adaptions and improvements, this looks a lot cleaner and easier to
understand.
some credit goes to @pigoz for the initial swift build support which
i could improve upon.
Fixes: #5478, #5393, #5152, #5151, #4615, #4476, #3978, #3746, #3739,
#2392, #2217
Disable by default.
This feature was added in 7eb342757, which allowed stream selection
in runtime. Problem with this atm is that FFmpeg will try to demux
every first packet of every track leading to noticeable delay opening
the URL.
This option can be changed to enabled by default or removed when
HLS/DASH demuxers are improved upstream.
Remove obsolete comment about FFmpeg ignoring non-http proxies
which was repeated in ytdl_hook before the feature was added.
Remove unnecessary conditions for not nil. Lua tables will always
return nil for non-existent keys.
Using the GL renderer for color conversion will make sure screenshots
will use the same conversion as normal video rendering. It can do this
for all types of screenshots.
The logic when to write 16 bit PNGs changes. To approximate the old
behavior, we decide by looking whether the source video format has more
than 8 bits per component. We apply this logic even for window
screenshots. Also, 16 bit PNGs now always include an unused alpha
channel. The reason is that FFmpeg has RGB48 and RGBA64 formats, but no
RGB064. RGB48 is 3 bytes and usually not supported by GPUs for
rendering, so we have to use RGBA64, which forces an alpha channel.
Will break for users who use --target-trc and similar options.
I considered creating a new gl_video context, but it could double GPU
memory use, so I didn't.
This uses FBOs instead of glGetTexImage(), because that increases the
chance it could work on GLES (e.g. ANGLE). Untested. No support for the
Vulkan and D3D11 backends yet.
Fixes#5498. Also fixes#5240, because the code for reading back is not
used with the new code path.
Before this commit, auto_loaded and lang were only set for the first
track in auto-loaded external files. Likewise, for the title and
lang arguments to the sub-add and audio-add commands.
Fixes#5432
Setting lavfi-complex at runtime will now forcefully reselect the tracks
as needed, even if it was a "proper" track selection via --aid or --vid.
Before this commit, it just failed and complained that the VO/AO was
already "used".
Requested.
This makes it actually somewhat simpler, and doesn't have any
disadvantages. It should also make some new features easier.
Mostly just moves code around.
The somewhat confusing thing is that many filters (including track->dec)
have a public struct, but to free them, you need to free the mp_filter
pointer itself (track->dec->f). The assignment wrote to a dangling
pointer, instead of removing the dangling pointer.
(Other than that, this idiom is actually nice.)
MPlayer used this to distinguish multiple decoder wrappers (such as
libavcodec vs. binary codec loader vs. builtin decoders). It lost
meaning in mpv as non-libavcodec things were dropped. Now it doesn't
serve any purpose anymore.
Parsing was removed quite a while ago, and the recent filter change
removed any use of the internal family field. Get rid of it.
FFmpeg only suppports http proxies and ignores it if
the resulting url is https. Also, no SOCKS.
Use it like `--ytdl-raw-options=proxy=[http://127.0.0.1:3128]` so
it doesn't confuse mpv because of the colons.
You need to pass it as an option because youtube-dl doesn't give
us the proxy.
Or just set `http_proxy` environment variable as recommended before.
Added example using -append, which doesn't need escaping.
Use the decoder wrapper that was introduced for video. This removes all
code duplication the old audio decoder wrapper had with the video code.
(The audio wrapper was copy pasted from the video one over a decade ago,
and has been kept in sync ever since by the power of copy&paste. Since
the original copy&paste was possibly done by someone who did not answer
to the LGPL relicensing, this should also remove all doubts about
whether any of this code is left, since we now completely remove any
code that could possibly have been based on it.)
There is some complication with spdif handling, and a minor behavior
change (it will restrict the list of codecs to spdif if spdif is to be
used), but there should not be any difference in practice.
Move dec_video.c to filters/f_decoder_wrapper.c. It essentially becomes
a source filter. vd.h mostly disappears, because mp_filter takes care of
the dataflow, but its remains are in struct mp_decoder_fns.
One goal is to simplify dataflow by letting the filter framework handle
it (or more accurately, using its conventions). One result is that the
decode calls disappear from video.c, because we simply connect the
decoder wrapper and the filter chain with mp_pin_connect().
Another goal is to eventually remove the code duplication between the
audio and video paths for this. This commit prepares for this by trying
to make f_decoder_wrapper.c extensible, so it can be used for audio as
well later.
Decoder framedropping changes a bit. It doesn't seem to be worse than
before, and it's an obscure feature, so I'm content with its new state.
Some special code that was apparently meant to avoid dropping too many
frames in a row is removed, though.
I'm not sure how the source code tree should be organized. For one,
video/decode/vd_lavc.c is the only file in its directory, which is a bit
annoying.
Get rid of the old vf.c code. Replace it with a generic filtering
framework, which can potentially handle more than just --vf. At least
reimplementing --af with this code is planned.
This changes some --vf semantics (including runtime behavior and the
"vf" command). The most important ones are listed in interface-changes.
vf_convert.c is renamed to f_swscale.c. It is now an internal filter
that can not be inserted by the user manually.
f_lavfi.c is a refactor of player/lavfi.c. The latter will be removed
once --lavfi-complex is reimplemented on top of f_lavfi.c. (which is
conceptually easy, but a big mess due to the data flow changes).
The existing filters are all changed heavily. The data flow of the new
filter framework is different. Especially EOF handling changes - EOF is
now a "frame" rather than a state, and must be passed through exactly
once.
Another major thing is that all filters must support dynamic format
changes. The filter reconfig() function goes away. (This sounds complex,
but since all filters need to handle EOF draining anyway, they can use
the same code, and it removes the mess with reconfig() having to predict
the output format, which completely breaks with libavfilter anyway.)
In addition, there is no automatic format negotiation or conversion.
libavfilter's primitive and insufficient API simply doesn't allow us to
do this in a reasonable way. Instead, filters can use f_autoconvert as
sub-filter, and tell it which formats they support. This filter will in
turn add actual conversion filters, such as f_swscale, to perform
necessary format changes.
vf_vapoursynth.c uses the same basic principle of operation as before,
but with worryingly different details in data flow. Still appears to
work.
The hardware deint filters (vf_vavpp.c, vf_d3d11vpp.c, vf_vdpaupp.c) are
heavily changed. Fortunately, they all used refqueue.c, which is for
sharing the data flow logic (especially for managing future/past
surfaces and such). It turns out it can be used to factor out most of
the data flow. Some of these filters accepted software input. Instead of
having ad-hoc upload code in each filter, surface upload is now
delegated to f_autoconvert, which can use f_hwupload to perform this.
Exporting VO capabilities is still a big mess (mp_stream_info stuff).
The D3D11 code drops the redundant image formats, and all code uses the
hw_subfmt (sw_format in FFmpeg) instead. Although that too seems to be a
big mess for now.
f_async_queue is unused.
Restores behaviour prior to aef2ed5dc1.
That change was apparently unpopular. However, given the amount of
complaining over how hard it is to change the defaults by rebinding every
key, I think the extra option introduced by this commit is justified.
Technically not all behaviour is restored, because now --no-osd-bar will
not instead display the msg text on seek. I think that feature was a
little weird and is now easy enough to remedy with the --osd-on-seek
option.
This reverts commit 9812e276aa.
This was apparently unpopular. I still think the pause OSD should be the
same as seek even if it's not visible by default, but it seems that
whether to display a given property change is currently conflated with
what to display.
The reverted behaviour can be restored by adding something like the
following to input.conf:
SPACE cycle pause; show_progress
This makes all the video/audio variants available for selection.
Might break with non-hls/dash, or even with dash if FFmpeg wasn't
compiled with the demuxer.
Requested. See manpage additions.
The main reason why this goes through the trouble to keep the
action/operation parameter separate is so that we don't expose some
option parser implementation details to the command (although that is a
relatively weak reason), and also to make it more different from the
"set" command, which can't support this type of option as it goes
through the property layer.
Fixes#5435.
And use it for 2 demuxer options. It could be used for more options
later. (Though the --cache options can not use this, because they use KB
as base unit.)
When overlay-add etc. is run, make sure the playlop is rerun so that it
considers actually redrawing the screen.
(I considered making the OSD code generally wakeup the player, but that
will probably lead to redundant wakeups, so I didn't bother.)
Fixes#5431.
Not very clean since there's a lot of potential unsafe urls that youtube-dl
can give us, depending on whether it's a single url, split tracks,
playlists, segmented dash, etc.
If you play a video with an external audio track, and do backwards
keyframe seeks, then audio can be missing. This is because a backwards
seek can end up way before the seek target (this is just how this seek
mode works). The audio file will be seeked at the correct seek target
(since audio usually has a much higher seek granularity), which results
in silence being played until the video reaches the originally intended
seek target.
There was a hack in audio.c to deal with this. Replace it with a
different hack. The new hack probably works about as well as the old
hack, except it doesn't add weird crap to the audio resync path (which
is some of the worst code here, so this is some nice preparation for
rewriting it). As a more practical advantage, it doesn't discard the
audio demuxer packet cache. The old code did, which probably ruined
seeking in youtube DASH streams.
A non-hacky solution would be handling external files in the demuxer
layer. Then chaining the seeks would be pretty easy. But we're pretty
far from that, because it would either require intrusive changes to the
demuxer layer, or wouldn't be flexible enough to load/unload external
files at runtime. Maybe later.
This is achieved by adding the new function get_term_status_msg that
returns the status message specified by the user, or the mpv default.
Previously, term_osd_print_status_lazy would exit early as soon as a
user status message had been set, which potentially skipped adding the
term_osd_bar if the user also requested that.
fixes#3280
The future direction might be not having such a user-visible filter at
all, similar to how vf_scale went away (or actually, redirects to
libavfilter's vf_scale).
package.config is available in 5.1, 5.2, 5.3 and luajit, so should be fine.
The first character is the path separator, so it's '\' on windows and '/'
on *nix.
This should also prevent cases where users download the wrong binary.
