On Mon, Jan 2, 2023 at 3:13 PM wolverin via Libav-user < [email protected]> wrote:
> *Output #0, rtsp, to 'rtsp://127.0.1.1:555 <http://127.0.1.1:555>':* > * Stream #0:0: Video: h264, yuv422p(tv, bt470bg/unknown/unknown), > 1280x720, q=2-31, 500 kb/s, 15 tbr, 90k tbn* > > > I compared such an approximate calculation of pts/dts in ffprobe for my > code and ffmpeg and they match until the real fps becomes different from > the calculated one, then I see either delays or frame losses in VLC. > > > You can not use 15 from video frame rate to calculate PTS when video is > variable frame rate. > > > ok, but then how do I calculate the pts/dts of each frame correctly??? > PTS is represented as relative time starting from 0 for start of file. PTS is just a int64_t number that tells relative time. To know time resolution one use timebase.num/den, so they are actually tied together with pts timestamp. If video is VFR than there are gaps e.g. non-monotonous increasing of pts from older to newer ones. Say time of frame is 5.5 seconds and timebase used is 1/90000 than time of 1 second would have value of 90000 stored in pts. 5.5 seconds would then be 5*90000 + 0.5*90000. Hope that you can conclude from this demonstration how to solve your problem. To rescale PTS from one timebase resolution to another one use av_rescale_q(). > I want my SoC ARM to provide maximum transcoding speed, this is especially > important for a resolution of 1920x1080 when fps is 8-11 > _______________________________________________ > Libav-user mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/libav-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". >
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