On Tue, Mar 4, 2025 at 10:47 PM Matthew Rademaker via ffmpeg-devel <ffmpeg-devel@ffmpeg.org> wrote: > > When playing out video to a Decklink SDI 4K card I've found that all/most > of the buffered frames get flushed instead of being displayed, essentially > shortening the video by the amount of pre-roll. I found a way to fix this > by adding a counter of outstanding frames, then delaying the call to > StopScheduledPlayback until all frames are returned. > > I would submit this as a patch, but this is my first attempt at any ffmpeg > development so I wanted to see if this was the best way to fix this issue. > Are the outstanding frames already counted some other way? Is blocking via > sleep ideal? The StopScheduledPlayback has a pts parameter, which I assume > means that it should only stop playback at that time - should this not > prevent the issue I am seeing? Why would it flush the frames?
Thanks for reaching out. This is a longstanding issue that has been reported before, and I just never got around to submitting a fix for (since for my particular use case, I actually want it to exit immediately, although I realize this isn't the common use case). The correct fix is simply to change the StopScheduledPlayback to not exit immediately (for which there is a specific argument, IIRC). You shouldn't need to do any sort of counters/timers to achieve the desired behavior. If you still can't get it to work, let me know and I'll take a look and submit the appropriate patch. Regards, Devin -- Devin Heitmueller, Senior Software Engineer LTN Global Communications o: +1 (301) 363-1001 w: https://ltnglobal.com e: devin.heitmuel...@ltnglobal.com _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
