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https://github.com/mpv-player/mpv
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aa03ee7300
The old implementation didn't work for the OGG case. Discard the old shit code (instead of fixing it), and write new shit code. The old code was already over a year old, so it's about time to rewrite it for no reason anyway. While it's true that the old code appears to be broken, the main reason to rewrite this is to make it simpler. While the amount of code seems to be about the same, both the concept and the actual tag handling are simpler. The result is probably a bit more correct. The packet struct shrinks by 8 byte. That fact that it wasted 8 bytes per packet for a rather obscure use case was the reason I started this at all (and when I found that OGG updates didn't work). While these 8 bytes aren't going to hurt, the packet struct was getting too bloated. If you buffer a lot of data, these extra fields will add up. Still quite some effort for 8 bytes. Fortunately, it's not like there are any managers that need to be convinced whether it's worth doing. The freedom to waste time on dumb shit. The old implementation attached the current metadata to each packet. When the decoder read the packet, the packet's metadata was made current. The new implementation stores metadata as separate list, and requires that the player frontend tells it the current playback time, which will be used to find the currently valid metadata. In both cases, the objective was to correctly update metadata even if a lot of data is buffered ahead (and to update them correctly when seeking within the demuxer cache). The new implementation is actually slightly more correct, because it uses the playback time for the metadata lookup. Consider if you have an audio filter which buffers 15 seconds (unfortunately such a filter exists), then the old code would update the current title 15 seconds too early, while the new one does it correctly. The new code also simplifies mixing the 3 metadata sources (global, per stream, ICY). We assume these aren't mixed in a meaningful way. The old code tried to be a bit more "exact". I didn't bother to look how the old code did this, but the new code simply always "merges" with the previous metadata, so if a newer tag removes a field, it's going to stick around anyway. I tried to keep it simple. Other approaches include making metadata a special sh_stream with metadata packets. This would have been conceptually clean, but the implementation would probably have been unnatural (and doesn't match well with libavformat's API anyway). It would have been nice to make the metadata updates chapter points (makes a lot of sense for the intended use case, web radio current song information), but I don't think it would have been a good idea to make chapters suddenly so dynamic. (Still an idea to keep in mind; the new code actually makes it easier to work towards this.) You could mention how subtitles are timed metadata, and actually are implemented as sparse packet streams in some formats. mp4 implements chapters as special subtitle stream, AFAIK. (Ironically, this is very not-ideal for files. It would be useful for streaming like web radio, but mp4 is extremely bad for streaming by design for other reasons.) bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla |
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| .. | ||
| codec_tags.c | ||
| codec_tags.h | ||
| cue.c | ||
| cue.h | ||
| demux_cue.c | ||
| demux_edl.c | ||
| demux_lavf.c | ||
| demux_libarchive.c | ||
| demux_mf.c | ||
| demux_mkv_timeline.c | ||
| demux_mkv.c | ||
| demux_null.c | ||
| demux_playlist.c | ||
| demux_raw.c | ||
| demux_timeline.c | ||
| demux.c | ||
| demux.h | ||
| ebml.c | ||
| ebml.h | ||
| matroska.h | ||
| packet.c | ||
| packet.h | ||
| stheader.h | ||
| timeline.c | ||
| timeline.h | ||