[FFmpeg-devel] [PATCH] mov.c: read fragment start dts from fragmented mp4

[Mika Raento]

Interesting. The input.mov created with ./ffmpeg -i
matrixbench_mpeg2.mpg -t 1  -frag_duration 200k input.mov does not
have tfra entries for all the moofs for the audio track. The single
tfra it has is not for the first moof, but the last one.

I'll improve the matching of the moofs and tfra entries.

Thanks again for your help.

    Mika

On 11 October 2014 14:21, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Sat, Oct 11, 2014 at 07:25:52AM +0300, Mika Raento wrote:
>> If present, an MFRA box and its TFRAs are read for fragment start times.
>>
>> Without this change, timestamps for discontinuous fragmented mp4 are
>> wrong, and cause audio/video desync and are not usable for generating
>> HLS.
>> ---
>>  libavformat/isom.h |  15 ++++++
>>  libavformat/mov.c  | 146 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 161 insertions(+)
>
> this appears to breaks timestamps for some files, i didnt investigate
> why
>
> ./ffmpeg -i matrixbench_mpeg2.mpg -t 1  -frag_duration 200k input.mov
> ./ffprobe input.mov -show_packets -print_format compact | grep audio
>
>  packet|codec_type=audio|stream_index=1|pts=0|pts_time=0.000000|dts=0|dts_time=0.000000|duration=N/A|duration_time=N/A|convergence_duration=N/A|convergence_duration_time=N/A|size=172|pos=17590|flags=K
>  packet|codec_type=audio|stream_index=1|pts=3840|pts_time=0.080000|dts=3840|dts_time=0.080000|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=315|pos=19048|flags=K
>  packet|codec_type=audio|stream_index=1|pts=4864|pts_time=0.101333|dts=4864|dts_time=0.101333|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=297|pos=19363|flags=K
>  packet|codec_type=audio|stream_index=1|pts=5888|pts_time=0.122667|dts=5888|dts_time=0.122667|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=9|pos=22964|flags=K
>  packet|codec_type=audio|stream_index=1|pts=6912|pts_time=0.144000|dts=6912|dts_time=0.144000|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=216|pos=22973|flags=K
>  packet|codec_type=audio|stream_index=1|pts=7936|pts_time=0.165333|dts=7936|dts_time=0.165333|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=327|pos=23521|flags=K
>  packet|codec_type=audio|stream_index=1|pts=8960|pts_time=0.186667|dts=8960|dts_time=0.186667|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=327|pos=23848|flags=K
> -packet|codec_type=audio|stream_index=1|pts=9984|pts_time=0.208000|dts=9984|dts_time=0.208000|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=330|pos=35835|flags=K
> -packet|codec_type=audio|stream_index=1|pts=11008|pts_time=0.229333|dts=11008|dts_time=0.229333|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=317|pos=36165|flags=K
> -packet|codec_type=audio|stream_index=1|pts=12032|pts_time=0.250667|dts=12032|dts_time=0.250667|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=326|pos=36482|flags=K
> +packet|codec_type=audio|stream_index=1|pts=48896|pts_time=1.018667|dts=48896|dts_time=1.018667|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=330|pos=35835|flags=K
> +packet|codec_type=audio|stream_index=1|pts=49920|pts_time=1.040000|dts=49920|dts_time=1.040000|duration=1024|duration_time=0.021333|convergence_duration=N/A|convergence_duration_time=N/A|size=317|pos=36165|flags=K
> ...
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> During times of universal deceit, telling the truth becomes a
> revolutionary act. -- George Orwell
>
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