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d725630b5f
This does what af_volume used to do. Since we couldn't relicense it, just rewrite it. Since we don't have a new filter mechanism yet, and the libavfilter is too inconvenient, do applying the volume gain in ao.c directly. This is done before handling the audio data to the driver. Since push.c runs a separate thread, and pull.c is called asynchronously from the audio driver's thread, the volume value needs to be synchronized. There's no existing central mutex, so do some shit with atomics. Since there's no atomic_float type predefined (which is at least needed when using the legacy wrapper), do some nonsense about reinterpret casting the float value to an int for the purpose of atomic access. Not sure if using memcpy() is undefined behavior, but for now I don't care. The advantage of not using a filter is lower complexity (no filter auto insertion), and lower latency (gain processing is done after our internal audio buffer of at least 200ms). Disavdantages include inability to use native volume control _before_ other filters with custom filter chains, and the need to add new processing for each new sample type. Since this doesn't reuse any of the old GPL code, nor does indirectly rely on it, volume and replaygain handling now works in LGPL mode. How to process the gain is inspired by libavfilter's af_volume (LGPL). In particular, we use exactly the same rounding, and we quantize processing for integer sample types by 256 steps. Some of libavfilter's copyright may or may not apply, but I think not, and it's the same license anyway.
97 lines
4.8 KiB
Plaintext
97 lines
4.8 KiB
Plaintext
mpv is a fork of mplayer2, which is a fork of MPlayer.
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mpv as a whole is licensed under the GNU General Public License GPL version 2
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or later (called GPLv2+ in this document, see LICENSE.GPL for full license
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text) by default, or the GNU Lesser General Public License LGPL version 2 or
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later (LGPLv2.1+ in this document, see LICENSE.LGPL for full license text) if
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built with the --enable-lgpl configure switch.
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Most source files are LGPLv2.1+ or GPLv2+, but some files are available under
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more liberal licenses, such as BSD, MIT, ISC, and possibly others. Look at the
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copyright header of each source file, and grep the sources for "Copyright" if
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you need to know details. C source files without Copyright notice are usually
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licensed as LGPLv2.1+. Also see the list of files with specific licenses below
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(not all files can have a standard license header).
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All new contributions must be LGPLv2.1+ licensed. Using a more liberal license
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compatible to LGPLv2.1+ is also ok.
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If changes are done on GPL code, must come with the implicit agreement that the
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project can relicense the changes to LGPLv2.1+ at a later point without asking
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the contributor. This is a safeguard for making potential relicensing of
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remaining GPL code to LGPLv2.1+ easier.
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For information about authors and contributors, consult the git log, which
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contains the complete SVN and CVS history as well.
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"v2.1+" in this context means "version 2.1 or later".
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Some libraries are GPLv2+ or GPLv3+ only. Building mpv with Samba support makes
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it GPLv3+.
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mpv can be built as LGPLv2.1+ with the --enable-lgpl configure option. To add
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a LGPL mode to mpv, MPlayer code had to be relicensed from GPLv2+ to LGPLv2.1+
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by asking the MPlayer authors for permission. Since permission could not be
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obtained from everyone, LGPL mode disables the following features, some of
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them quite central:
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- no audio filtering, which breaks: --af, pitch correction, fine control over
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downmix/upmix/resampling behavior
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- Linux X11 video output
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- BSD audio output via OSS
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- NVIDIA/Linux hardware decoding (vdpau, although nvdec usually works)
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- Linux TV input
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- minor features: jack, DVD, CDDA, SMB, CACA, legacy direct3d VO
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Some of these will be fixed in the future. The intended use for LGPL mode is
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with libmpv, and currently it's not recommended to build mpv CLI in LGPL mode
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at all.
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The following files are still GPL only (--enable-lgpl disables them):
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audio/filter/* will be replaced with new filter chain
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audio/filter/af_format.c mostly LGPL (except af glue code)
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audio/filter/af_lavc3enc.c as above
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audio/filter/af_lavfi.c as above
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audio/filter/af_scaletempo.c as above
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audio/filter/af_rubberband.c as above
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audio/out/ao_jack.c will stay GPL
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audio/out/ao_oss.c will stay GPL
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audio/audio.* needed by af code only
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demux/demux_tv.c will stay GPL
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stream/ai_* will stay GPL (TV code)
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stream/audio_in.* will stay GPL (TV code)
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stream/dvb* must stay GPL
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stream/frequencies.* must stay GPL
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stream/stream_cdda.c unknown
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stream/stream_dvb.* must stay GPL
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stream/stream_dvd.c unknown
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stream/stream_dvd_common.* unknown
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stream/stream_dvdnav.c unknown
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stream/stream_smb.c will stay GPLv3
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stream/stream_tv.c will stay GPL
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stream/tv* will stay GPL
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video/out/opengl/hwdec_vaglx.c GPL
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video/out/vo_caca.c unknown
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video/out/vo_direct3d.c unknown
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video/out/vo_vaapi.c probably impossible (some company's code)
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video/out/vo_vdpau.c probably impossible (nVidia's code)
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video/out/vo_x11.c probably impossible
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video/out/vo_xv.c probably impossible
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video/out/x11_common.* probably impossible
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video/vdpau.c hard (GPL-only parts must be ifdefed)
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video/vdpau.h unknown
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video/vdpau_mixer.* actual code must be rewritten
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DOCS/man/ GPLv2+
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bootstrap.py unknown license, probably GPLv2+ or LGPLv2+
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etc/mplayer-input.conf unknown license, probably GPLv2+
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mpv.desktop unknown license, probably GPLv2+
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etc/restore-old-bindings.conf unknown license, probably GPLv2+
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The following files contain some optional GPL code (--enable-lgpl disables it):
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options/parse_commandline.c dvd:// expansion
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player/audio.c libaf glue code
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None of the exceptions listed above affect the final binary if it's built as
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LGPL. Linked libraries still can affect the final license (for example if
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FFmpeg was built as GPL).
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