[FFmpeg-devel] Not-very-good timestamps with fragmented mp4 input

Mika Raento mikie at iki.fi
Wed Oct 8 07:54:06 CEST 2014


I have a number of ISMV files that have discontinuities (missing
frames between fragments). Using these as input to ffmpeg doesn't work
very well - the discontinuities are not reflected in the dts or pts,
e.g., using ffprobe -show_packets. Hence there are audio/video sync
problems and with large gaps I'm not able to create working HLS

Ffmpeg does not read the MFRA (fragmentation index), which would
contain the fragment start times.

I don't know enough to say if the timestamp information might be
duplicated in the mdat.

Would the solution be to read the MFRA in mov.c?

(there is also an alternate MS-specific uuid atom that contains the
duration and time data for each moof, but my files don't have those)

Or am I missing something?


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