Does ffprobe take 20s? On Tue, Jul 3, 2018 at 2:23 AM, Evan <cerebro.alex...@gmail.com> wrote: > Hi everyone, > > I'm developping a media player featuring advanced video/frame processing. > To be able to seek to any particular frame, I need to know, for each frame, > its presentation time and if available, if it's a key frame or not. The > latter is optional, really. > > To do that I build an "index" once the media is valid and opened. > It's a basically a loop, fetching a packet, checking if it's the video > stream I'm interested in, feeding the codec until he can produces a frame > or reaching the end of the file. > > This is perfectly working but it's way too long for me, like 20 seconds for > a ~800MB mp4/h264 file. > I'm considering the following options: > - building the index in the background while playing the media: I guess > I'll have to copy the decoder context to not mix both processes but I > expect having playback (stuttering) issues. > - use multiple threads: from what I read, I can only use one thread for a > stream. I may eventually use two threads, one for video and one for audio > but I want to speed up video decoding fisrt. > - use the GPU to decode frames faster: while it sounds like a good idea, I > have to add two constraints: I'm on Windows 7 (and soon, Windows 10) and I > want a generic approach so not H.264-only. > - decode only packets: it's tempting but I think I will either loose > timestamp information or precision (because of I, P, B frames. > - use an option (av_dict_set) to do a dummy frame decoding: is there > anything like that? > - use reference counting to avoid costly frame allocations: I already tried > that but didn't see any difference. > > For now, I will measure time elapsed in each piece of code in order to > pinpoint lengthy operations. > If you guys have any hint, I'd be glad to hear them. > > Thanks. > _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
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