mirror of https://github.com/mpv-player/mpv
a3823ce0e0
See manpage additions. This has been a topic in MPlayer/mplayer2/mpv since forever. But since libavcodec multi-threaded decoding was added, I've always considered this pointless. libavcodec requires you to "preload" it with packets, and then you can pretty much avoid blocking on it, if decoding is fast enough. But in some cases, a decoupled decoder thread _might_ help. Users have for example come up with cases where decoding video in a separate process and piping it as raw video to mpv helped. (Or my memory is false, and it was about vapoursynth filtering, who knows.) So let's just see whether this helps with anything. Note that this would have been _much_ easier if libavcodec had an asynchronous (or rather, non-blocking) API. It could probably have easily gained that with a small change to its multi-threading code and a small extension to its API, but I guess not. Unfortunately, this uglifies f_decoder_wrapper quite a lot. Part of this is due to annoying corner cases like legacy frame dropping and hardware decoder state. These could probably be prettified later on. There is also a change in playloop.c: this is because there is a need to coordinate playback resets between demuxer thread, decoder thread, and playback logic. I think this SEEK_BLOCK idea worked out reasonably well. There are still a number of problems. For example, if the demuxer cache is full, the decoder thread will simply block hard until the output queue is full, which interferes with seeking. Could also be improved later. Hardware decoding will probably die in a fire, because it will run out of surfaces quickly. We could reduce the queue to size 1... maybe later. We could update the queue options at runtime easily, but currently I'm not going to bother. I could only have put the lavc wrapper itself on a separate thread. But there is some annoying interaction with EDL and backward playback shit, and also you would have had to loop demuxer packets through the playloop, so this sounded less annoying. The food my mother made for us today was delicious. Because audio uses the same code, also for audio (even if completely pointless). Fixes: #6926 |
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| .. | ||
| man | ||
| client-api-changes.rst | ||
| compatibility.rst | ||
| compile-windows.md | ||
| contribute.md | ||
| edl-mpv.rst | ||
| encoding.rst | ||
| interface-changes.rst | ||
| mplayer-changes.rst | ||
| release-policy.md | ||
| tech-overview.txt | ||
| waf-buildsystem.rst | ||