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Generally, using x86 SIMD efficiently (or crash-free) requires aligning all data on boundaries of 16, 32, or 64 (depending on instruction set used). 64 bytes is needed or AVX-512, 32 for old AVX, 16 for SSE. Both FFmpeg and zimg usually require aligned data for this reason. FFmpeg is very unclear about alignment. Yes, it requires you to align data pointers and strides. No, it doesn't tell you how much, except sometimes (libavcodec has a legacy-looking avcodec_align_dimensions2() API function, that requires a heavy-weight AVCodecContext as argument). Sometimes, FFmpeg will take a shit on YOUR and ITS OWN alignment. For example, vf_crop will randomly reduce alignment of data pointers, depending on the crop parameters. On the other hand, some libavfilter filters or libavcodec encoders may randomly crash if they get the wrong alignment. I have no idea how this thing works at all. FFmpeg usually doesn't seem to signal alignment internal anywhere, and usually leaves it to av_malloc() etc. to allocate with proper alignment. libavutil/mem.c currently has a ALIGN define, which is set to 64 if FFmpeg is built with AVX-512 support, or as low as 16 if built without any AVX support. The really funny thing is that a normal FFmpeg build will e.g. align tiny string allocations to 64 bytes, even if the machine does not support AVX at all. For zimg use (in a later commit), we also want guaranteed alignment. Modern x86 should actually not be much slower at unaligned accesses, but that doesn't help. zimg's dumb intrinsic code apparently randomly chooses between aligned or unaligned accesses (depending on compiler, I guess), and on some CPUs these can even cause crashes. So just treat the requirement to align as a fact of life. All this means that we should probably make sure our own allocations are 64 bit aligned. This still doesn't guarantee alignment in all cases, but it's slightly better than before. This also makes me wonder whether we should always override libavcodec's buffer pool, just so we have a guaranteed alignment. Currently, we only do that if --vd-lavc-dr is used (and if that actually works). On the other hand, it always uses DR on my machine, so who cares.
mpv
- External links
- Overview
- System requirements
- Downloads
- Changelog
- Compilation
- FFmpeg vs. Libav
- FFmpeg ABI compatibility
- Release cycle
- Bug reports
- Contributing
- Relation to MPlayer and mplayer2
- License
- Contact
External links
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.
Releases can be found on the release list.
System requirements
- A not too ancient Linux, Windows 7 or later, or OSX 10.8 or later.
- A somewhat capable CPU. Hardware decoding might help if the CPU is too slow to
decode video in realtime, but must be explicitly enabled with the
--hwdecoption. - A not too crappy GPU. mpv is not intended to be used with bad GPUs. There are
many caveats with drivers or system compositors causing tearing, stutter,
etc. On Windows, you might want to make sure the graphics drivers are
current. In some cases, ancient fallback video output methods can help
(such as
--vo=xvon Linux), but this use is not recommended or supported.
Downloads
For semi-official builds and third-party packages please see mpv.io/installation.
Changelog
There is no complete changelog; however, changes to the player core interface are listed in the interface changelog.
Changes to the C API are documented in the client API changelog.
The release list has a summary of most of the important changes on every release.
Changes to the default key bindings are indicated in restore-old-bindings.conf.
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 the
repository. The ./bootstrap.py script 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.
Example:
./bootstrap.py
./waf configure
./waf
./waf install
Essential dependencies (incomplete list):
- gcc or clang
- X development headers (xlib, xrandr, xext, xscrnsaver, xinerama, libvdpau, libGL, GLX, EGL, xv, ...)
- Audio output development headers (libasound/ALSA, pulseaudio)
- FFmpeg libraries (libavutil libavcodec libavformat libswscale libavfilter and either libswresample or libavresample)
- zlib
- iconv (normally provided by the system libc)
- libass (OSD, OSC, text subtitles)
- Lua (optional, required for the OSC pseudo-GUI and youtube-dl integration)
- libjpeg (optional, used for screenshots only)
- uchardet (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 or GnuTLS (have to be explicitly enabled when compiling FFmpeg)
- libx264/libmp3lame/libfdk-aac if you want to use encoding (have to be explicitly enabled when compiling FFmpeg)
- For native DASH playback, FFmpeg needs to be built with --enable-libxml2 (although there are security implications).
- For good nvidia support on Linux, make sure nv-codec-headers is installed and can be found by configure.
- Libav support is broken. (See section below.)
Most of the above libraries are available in suitable versions on normal Linux distributions. For ease of compiling the latest git master of everything, you may wish to use the separately available build wrapper (mpv-build) which first compiles FFmpeg libraries and libass, and then compiles the player statically linked against those.
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 FFmpeg. Libav support is currently broken, because they did not add certain FFmpeg API changes which mpv relies on.
FFmpeg ABI compatibility
mpv does not support linking against FFmpeg versions it was not built with, even if the linked version is supposedly ABI-compatible with the version it was compiled against. Expect malfunctions, crashes, and security issues if you do it anyway.
The reason for not supporting this is because it creates far too much complexity with little to no benefit, coupled with absurd and unusable FFmpeg API artifacts.
Newer mpv versions will refuse to start if runtime and compile time FFmpeg library versions mismatch.
Release cycle
Every other month, an arbitrary git snapshot is made, and is assigned a 0.X.0 version number. No further maintenance is done.
The goal of releases is to make Linux distributions happy. Linux distributions are also expected to apply their own patches in case of bugs and security issues.
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. Follow the template's instructions or the issue will likely be ignored or closed as invalid.
Using the bug tracker as place for simple questions is fine but IRC is recommended (see Contact below).
Contributing
Please read contribute.md.
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.
You can check the wiki or the issue tracker for ideas on what you could contribute with.
Relation to MPlayer and mplayer2
mpv is a fork of MPlayer. Much has changed, and in general, mpv should be considered a completely new program, rather than a MPlayer drop-in replacement.
For details see FAQ entry.
If you are wondering what's different from mplayer2 and MPlayer, an incomplete and largely unmaintained list of changes is located here.
License
GPLv2 "or later" by default, LGPLv2.1 "or later" with --enable-lgpl.
See details.
Contact
Most activity happens on the IRC channel and the github issue tracker.
- GitHub issue tracker: issue tracker (report bugs here)
- User IRC Channel:
#mpvonirc.freenode.net - Developer IRC Channel:
#mpv-develonirc.freenode.net