Remove coded_width and coded_height. This was originally added in commit
fd7dde40, when BITMAPINFOHEADER was killed. The separate fields became
redundant in commit e68f4be1. Remove them (nothing passed to the
decoders actually changes with _this_ commit).
The Matroska timeline code was the only thing which still used the
demuxer.type field. This field explicitly identifies a demuxer
implementation. The purpose of the Matroska timeline code was to reject
files that are not Matroska. But it already forces the Matroska format,
meaning loading will explicitly only use the Matroska demuxer. If the
demuxer can't open the file, no other demuxer will be tried, and thus
checking the field is redundant.
The change in demux_mkv_timeline.c removes the if condition, and
unindents the if body.
This removes the delay when switching audio tracks in mkv or mp4 files.
Other formats are not enabled, because it's not clear whether the
demuxers fulfill the requirements listed in demux.h. (Many formats
definitely do not with libavformat.)
Background:
The demuxer packet cache buffers a certain amount of packets. This
includes only packets from selected streams. We discard packets from
other streams for various reasons. This introduces a problem: switching
to a different audio track introduces a delay. The delay is as big as
the demuxer packet cache buffer, because while the file was read ahead
to fill the packet buffer, the process of reading packets also discarded
all packets from the previously not selected audio stream. Once the
remaining packet buffer has been played, new audio packets are available
and you hear audio again.
We could probably just not discard packets from unselected streams. But
this would require additional memory and CPU resources, and also it's
hard to tell when packets from unused streams should be discarded (we
don't want to keep them forever; it'd be a memory leak).
We could also issue a player hr-seek to the current playback position,
which would solve the problem in 1 line of code or so. But this can be
rather slow.
So what we do in this commit instead is: we just seek back to the
position where our current packet buffer starts, and start demuxing from
this position again. This way we can get the "past" packets for the
newly selected stream. For streams which were already selected the
packets are simply discarded until the previous position is reached
again.
That latter part is the hard part. We really want to skip packets
exactly until the position where we left off previously, or we will skip
packets or feed packets to the decoder twice. If we assume that the
demuxer is deterministic (returns exactly the same packets after a seek
to a previous position), then we can try to check whether it's the same
packet as the one at the end of the packet buffer. If it is, we know
that the packet after it is where we left off last time.
Unfortunately, this is not very robust, and maybe it can't be made
robust. Currently we use the demux_packet.pos field as unique packet
ID - which works fine in some scenarios, but will break in arbitrary
ways if the basic requirement to the demuxer (as listed in the demux.h
additions) are broken. Thus, this is enabled only for the internal mkv
demuxer and the libavformat mp4 demuxer.
(libavformat mkv does not work, because the packet positions are not
unique. Probably could be fixed upstream, but it's not clear whether
it's a bug or a feature.)
Until now, some packets could return the same file position if they were
split off from a Matroska-level packet. This was perfectly fine, because
the file position isn't used for anything overly important (it uses it
to estimate playback position if no other information is available). The
following commit will use the demux_packet.pos field as unique ID (as a
simplification), so make the demuxer export more finegrained
information.
Also, the last_filepos field didn't have to be global, at least not
anymore.
Reindent the whole handle_realaudio() function, and make the surrouding
if block return early instead.
Also contains some cosmetics to the sipr swapping, which hopefully does
not change the semantics, but is untested (the kind of cosmetic changes
everyone loves so much). May the person responsible for sipr rot in
hell. (It was probably done to obfuscate the codec?)
Staring at the code, it doesn't look like the extra code for "normal"
audio is needed. Most of it looks like artifacts from the previous code
structure (much of it was added in the initial commit). I couldn't find
a sample that uses this code path to fully confirm this, though.
I suppose it could lead to subtle changes in behavior in presence of
realvideo files that change aspect radio. With the only sample I had
available, the behavior actually improved (azumi.mkv from the MPlayer
samples FTP; when starting playback in the middle it used the wrong
aspect ratio).
Appears to work, so we can drop some code. For some really odd reason,
the descrambling done on the timestamp requires millisecond units (due
to the "algorithm", not the libavcodec API).
Fixes vp9 missing timestamps. This requires a brand new libavcodec (the
patch for this was just applied to FFmpeg git master).
The timestamp mangling is applied to VP9 only. It'd probably work with
other codecs, but it's not needed. It could break in various ways, so
it has to be explicitly checked for every enabled codec.
Makes it somewhat more uniform, and breaks up the awfully deep nesting.
This implicitly changes multiple small details, rather than only moving
code around. In particular, this computes the packet fields first and
parses them afterwards, which is needed for the next commit.
Might fix behavior with mkv files that use ordered chapters and have
cover art tags. In my opinion, this should actually have worked (because
cover art pseudo-tracks are strictly appended), but I don't have a
sample file to test at hand.
The VP9 codec parser has a bug: it doesn't set the data/size pointers
passed to it. As I understand, it must always do this, and in fact, if
it doesn't some libavcodec generic code would be in trouble too.
This helps with #1448, but is not the full fix for it. The codec parser
must be fixed in libavcodec itself.
Removes an annoying "No video PTS! Making something up." warning.
Mark it as keyframe, which is needed to prevent strange behavior with
PNG. Also, don't leak the picture data.
For some codecs, we need to invoke a codec parser (because libavcodec
will run into trouble otherwise). This was done based on the Matroska
codec field.
But this ignores handling of vfw-muxed files, which use a pseudo-codec
to signal presence of vfw structures, which we must unmangle to get the
real codec. Handle this by rearranging the code.
This fixes at least mp3-in-mkv for vfw-muxed files; typically old files.
This message can happen a lot for mkv files which index clusters in the
seekhead (which is also broken non-sense, but that's a different story).
Also remove a duplicate define from matroska.h.
The code could as well be in demux.c, but it's better to avoid
accidental clashes with demux_lavf.c.
FFmpeg provides no way yet to map a mime type to a codec, so do it
manually. (It _can_ map a mime type to an "input format", but not a
codec.)
Fixes#1374.
The most awesome codec, not.
The actual code for svq3 is actually just the part that checks for
MKV_V_QUICKTIME (no other QT-muxed codecs are supported). The rest is
minor refactoring, that actually improves the code in general.
This is just enough to support the 2 svq3-in-mkv sample files I have.
All of this is basically due to how MPlayer's codecs.conf worked. It
had a demuxer-interface based an AVI, using FourCCs and data structures
found in AVI. FourCCs were used to map streams to decoders. For codecs
not supported by AVI, "MPlayer internal" FourCCs were made up.
codec_tags.c is there to bridge demuxers written against the old API to
the mpv one. By now, only demux_mkv.c needs this (because demux_mkv is
the only serious demuxer left - preferably, we should use libavformat
for mkv too, but I can't see this happening any time soon, because
libavformat _still_ doesn't support segment linking). But the codec
tables are full of weird stuff automatically extracted from the old
codecs.conf tables. Most of it isn't needed for mkv.
Remove all custom tags, readd those used by demux_mkv.c internally
(see vinfo and mkv_audio_tag tables). The rest is handled by the
tables provided by libavformat, which includes AVI and QT tags.
It was more complicated than necessary.
The behavior changes slightly. Now it might pass through extradata when
it didn't before (hopefully harmless), and doesn't fail with an error if
extradata is not available, even though it's needed (harmless, will fail
either way).
The if branch has a weak check to test whether the codec_id is the short
ID, and handles the long IDs in the else branch. The long IDs are all
longer than 12 bytes long, so hardcoding the string offset to get the
trailing part of the name makes sense. But the if condition checks for
another thing, which could get the else branch run even if the codec_id
is short.
Fix the bogus control flow and check if the codec_id is long enough. One
of these checks could be considered redundant, but include them both for
defensive coding.
Do a minimal check on data read with stream_peek(). This could help with
probing from unseekable streams in some situations. (We could check the
entire EBML and Matroska headers, but probably not worth the trouble. We
could also seek back to the start, which demux.c doesn't do, but which
would work usually - also not worth the trouble.)
Make the changes started in commit c827ae5f more eloborate, and provide
an option to control the amount of data read before the seek-target. To
achieve this, rewrite the loop that finds the lowest still acceptable
target cluster. It is now searched by time instead of file position. The
behavior (both with and without preroll option) may be different from
before this change, although it shouldn't be worse.
The change demux_mkv_read_cues() fixes a bug: when seeking after playing
normally, the code would erroneously assume that durations are set. This
doesn't happen if the first operation after loading was a seek instead
of playback.
Revert commit 24e52f66; even though the old beheavior doesn't make sense
(as the commit message assured), it turns out that this works better:
typically, it means preroll will start from the previous video key frame
(the video CUE index will contain clusters with video key frames only),
which often coincides with subtitle changes. Thus the old behavior is
actually better.
Change the code that uses CueDuration elements. Instead of merely
checking whether preroll should be done, find the first cluster that
needs to be read to get all subtitle packets. (The intention is to
compensate for the enlarged preroll cluster-range due to reverting
commit 24e52f66.)
This considered only index entries that were for the same track ID as
the track used for seeking. This doesn't make much sense for preroll;
it'll just possibly skip clusters, and select an earlier cluster.
One possible negative side-effect is that the preroll might be too tight
now, and miss subtitle packets more often.
The demuxer has a hack to seek to the cluster before the target cluster
in order to "catch" subtitle lines that start before the seek target,
but overlap with the video after the seek target.
Avoid this hack if the cue index indicates that there are no overlapping
subtitle packets that can be caught by seeking to the previous cluster.
Nothing is done with them yet. This is preparation for the following
commit.
CueRelativePosition isn't even saved anywhere, because I don't intend to
use it. (Too messy for no gain.)
Instead of indexing only 1 packet per cluster (which is enough for
working seeking), add every packet to the index.
Since on seek, we go through every single index entry, this probably
makes seeking slower. On the other hand, this code is used for files
without index only (e.g. incomplete files), so it probably doesn't
matter much.
Preparation for the following commits.
This mechanism was introduced for Opus, and allows correct skipping of
"preroll" data, as well as discarding trailing audio if the file's
length isn't a multiple of the audio frame size.
Not sure how to handle seeking. I don't understand the purpose of the
SeekPreRoll element.
This was tested with correctness_trimming_nobeeps.opus, remuxed to mka
with mkvmerge v7.2.0. It seems to be correct, although the reported file
duration is incorrect (maybe a mkvmerge issue).
Instead of defining a separate data structure in the core.
For some odd reason, demux_chapter exported the chapter time in
nano-seconds. Change that to the usual timestamps (rename the field
to make any code relying on this to fail compilation), and also remove
the unused chapter end time.
Makes it behave slightly better for VP9. This is also the behavior
libavformat has.
Also while we're at it, don't set duration except for the first packet.
Normally we don't use the duration except for subtitles (which are never
parsed or "laced"), so this should make no observable difference.
See previous commits. This finally replaces directly reading the file
data into a struct with reading them manually. In theory this is more
portable (no alignment issues and other things). For the most part,
it's nice seeing this gone.
