Hello, I want to try and use the libavfilter API to overlay bitmap subtitles on video from a realtime source. This seems difficult/impossible to do with the current API hence asking on the main devel list.
Some questions: 1: How do I know the end to end latency of the pipeline? Is it fixed, does it vary? This matters because my wallclock PTS needs addition of this latency. 2: Do I need to interleave video and subtitles (e.g VSVSVSVS) in monotonically increasing order? What happens if the subtitles stop for a bit (magic queues are bad in a realtime environment)? My timestamps are guaranteed to be the same though. 3: My world is CFR but libavfilter is VFR - how does the API know when to start releasing frames? Does this add one frame of video latency then until it waits for the next video frame to arrive? 4: What are the differences between the FFmpeg and libav implementations? FFmpeg uses a framesync and libav doesn't? 5: I know exactly which frames have associated subtitle bitmaps or not, is there a way I can overlay without an extra frame delay? If possible please answer these questions with respect to libavfilter only (no lavc/lavf specifics) Kieran _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
