[Libav-user] Identical timestamps for different frames

[Nicolás Dato]

Hi,
I have an MPEG TS file in which the H264 video stream has the
following PTS/DTS pattern:


F1 ->  PTS:  4470324556                DTS:           -
F2 ->  PTS:  4470326057                DTS:           -
F3 ->  PTS:  4470333565                DTS:  4470327559
F4 ->  PTS:  4470335066                DTS:  4470329060
F5 ->  *PTS:  4470330562*              DTS:           -
F6 ->  PTS:  4470332063                DTS:           -
F7 ->  PTS:  4470345577                *DTS:  4470330562*
F8 ->  PTS:  4470347078                DTS:  4470332063
F9 ->  PTS:  4470336568                DTS:           -
F10 ->  PTS:  4470338069                DTS:           -
F11 ->  PTS:  4470339571                DTS:           -

If you pay attention to to the starred timestamps, you'll notice they
are the same. According to my knowledge (ISO 13818-1:2007 Annex D.0.2)
, if a video frame doesn't have DTS, the PTS can be interpreted as
being both the PTS and DTS. So, how should I provide these frames to
the decoder? Does avcodec_decode_videoX() require the input frames to
be reordered so as to have the DTSs be monotonically incremental?
This issue happens repeatedly in this file.

If needed, I could provide a sample file with this pattern.

Thanks in advance.


-- 

Nicolas Dato
Investigación y Desarrollo
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