wm4
f9f2e1cc4e
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.)
mpv
Overview
mpv is a media player based on MPlayer and mplayer2. It supports a wide variety of video file formats, audio and video codecs, and subtitle types.
If you are wondering what's different from mplayer2 and MPlayer you can read more about the changes.
Compilation
Compiling with full features requires development files for several external libraries. Below is a list of some important requirements.
The mpv build system uses waf but we don't store it in your source tree. The script './bootstrap.py' will download the latest version of waf that was tested with the build system.
For a list of the available build options use ./waf configure --help. If
you think you have support for some feature installed but configure fails to
detect it, the file build/config.log may contain information about the
reasons for the failure.
NOTE: To avoid cluttering the output with unreadable spam, --help only shows
one of the two switches for each option. If the option is autodetected by
default, the --disable-*** switch is printed; if the option is disabled by
default, the --enable-*** switch is printed. Either way, you can use
--enable-*** or --disable-** regardless of what is printed by --help.
To build the software you can use ./waf build: the result of the compilation
will be located in build/mpv. You can use ./waf install to install mpv
to the prefix after it is compiled.
NOTE: Using the old build system (with ./old-configure) should still work,
but will be removed in a future version of mpv.
Essential dependencies (incomplete list):
- gcc or clang
- X development headers (xlib, X extensions, libvdpau, libGL, libXv, ...)
- Audio output development headers (libasound/ALSA, pulseaudio)
- FFmpeg libraries (libavutil libavcodec libavformat libswscale libavfilter and either libswresample or libavresample) At least FFmpeg 2.1.4 or Libav 10 is required.
- zlib
- iconv (normally provided by the system libc)
- libass
- Lua (optional, required for the OSC pseudo-GUI and youtube-dl integration)
- libjpeg (optional, used for screenshots only)
- Enca (optional, for subtitle charset detection)
- vdpau and vaapi libraries for hardware decoding on Linux (optional)
Libass dependencies:
- gcc or clang, yasm on x86 and x86_64
- fribidi, freetype, fontconfig development headers (for libass)
- harfbuzz (optional, required for correct rendering of combining characters, particularly for correct rendering of non-English text on OSX, and Arabic/Indic scripts on any platform)
FFmpeg dependencies:
- gcc or clang, yasm on x86 and x86_64
- OpenSSL (has to be explicitly enabled when compiling ffmpeg)
- libx264/libmp3lame/libfdk-aac if you want to use encoding (has to be explicitly enabled when compiling ffmpeg)
- Libav also works, but some features will not work. (See section below.)
Most of the above libraries are available in suitable versions on normal Linux distributions. However FFmpeg is an exception (distro versions may be too old to work at all or work well). For that reason you may want to use the separately available build wrapper (mpv-build) that first compiles FFmpeg libraries and libass, and then compiles the player statically linked against those.
If you are running Mac OSX and using homebrew we provide homebrew-mpv, an up to date formula that compiles mpv with sensible dependencies and defaults for OSX.
If you want to build a Windows binary, you either have to use MSYS2 and MinGW, or cross-compile from Linux with MinGW. See Windows compilation.
FFmpeg vs. Libav
Generally, mpv should work with the latest release as well as the git version of both FFmpeg and Libav. But FFmpeg is preferred, and some mpv features work with FFmpeg only. See the wiki article about the issue.
Release cycle
Every few months, a new release is cut off of the master branch and is assigned a 0.X.0 version number.
As part of the maintenance process, minor releases are made, which are assigned 0.X.Y version numbers. Minor releases contain bug fixes only. They never merge the master branch, and no features are added to it. Only the latest release is maintained.
The goal of releases is to provide stability and an unchanged base for the sake of Linux distributions. If you want the newest features, just use the master branch, which is stable most of the time, except sometimes, when it's not.
Releases other than the latest release are unsupported and unmaintained.
See the release policy document for more information.
Bug reports
Please use the issue tracker provided by GitHub to send us bug reports or feature requests.
Contributing
For small changes you can just send us pull requests through GitHub. For bigger changes come and talk to us on IRC before you start working on them. It will make code review easier for both parties later on.
Contact
Most activity happens on the IRC channel and the github issue tracker. The mailing lists are mostly unused.
- Github issue tracker: issue tracker (report bugs here)
- User IRC Channel:
#mpv-playeronirc.freenode.net - Developer IRC Channel:
#mpv-player-devonirc.freenode.net - Users Mailing List:
mpv-users@googlegroups.com(Archive / Subscribe). - Devel Mailing List:
mpv-devel@googlegroups.com(Archive / Subscribe)
To contact the mpv team in private write to mpv-team@googlegroups.com. Use
only if discretion is required.