Hm. After fixing the obvious problems with matching moofs with tfra
entries I noticed that the timestamps aren't right even after that.
AFAICT, ffmpeg's fragmentation code puts dts in the tfra time. In movenc.c:
mov->tracks[i].frag_start += mov->tracks[i].start_dts +
mov->tracks[i].track_duration -
mov->tracks[i].cluster[0].dts;
Whereas l-smash's code definitely tries to put a presentation timestamp there.
I wonder if we should add some flags after all - I don't think it'll
be easy to automatically detect what the creating program has been
doing.
I'll submit the version with fixed matching shortly.
Mika
On 11 October 2014 15:27, Mika Raento <mi...@iki.fi> wrote:
> 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 <michae...@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
>>
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel@ffmpeg.org
>> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
