On 2012-11-26 10:46:27 +0100, Janne Grunau wrote: > On 2012-11-25 23:10:26 +0000, Måns Rullgård wrote: > > Janne Grunau <janne-li...@jannau.net> writes: > > > > > Although sample count and delta are in ISO 14496-12 specified as > > > unsigned files exists were interpreting it as signed integer makes > > > more sense (see mp4-negative-stts-problem.mp4). > > > > Can someone _please_ explain how a negative duration can ever many any > > sense at all? Or count, if that's the one that's causing problems. > > It looks as if the video frames in mp4-negative-stts-problem.mp4 are > stored in presentation order and the negative stts sample duration is > required to deduce the dts correctly. WTF!
-ENOTENOUGHCOFFEE, strike that. It's actually the audio stream, which I completely missed due to a stray -an in the command line. The file seems to be produced by camera. There are unfortunately no hints of brand or model in the metadata. It looks like ithere is a bug in the stts writing code: [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 0: sample_count=2, sample_duration=1023 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 1: sample_count=1, sample_duration=2362 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 2: sample_count=2, sample_duration=1023 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 3: sample_count=1, sample_duration=157 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 4: sample_count=3, sample_duration=1023 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 5: sample_count=1, sample_duration=1338 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 6: sample_count=2, sample_duration=1023 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 7: sample_count=1, sample_duration=2362 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 8: sample_count=3, sample_duration=1023 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 9: sample_count=1, sample_duration=-866 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 10: sample_count=2, sample_duration=1023 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 11: sample_count=1, sample_duration=2362 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 12: sample_count=3, sample_duration=1023 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 13: sample_count=1, sample_duration=-866 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 14: sample_count=2, sample_duration=1023 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 15: sample_count=1, sample_duration=2362 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x2c476a0] 16: sample_count=2, sample_duration=1023 The sample duration is only used to deduce dts which is still monotonically increasing. Janne _______________________________________________ libav-devel mailing list libav-devel@libav.org https://lists.libav.org/mailman/listinfo/libav-devel
