[FFmpeg-user] Duplication of time stamps when concatenating .mkv files

[Stefano Sabatini]

On date Tuesday 2015-02-03 13:16:00 -0800, Luke Paone wrote:
> Hi,
> 
> I am running into some issues when splitting and then concatenating files
> using ffmpeg.
> 
> I am using the following command line to split the files:
[...]
> Here is the FFPROBE out put for 2 frames after the merge:
> 
> ...
> [FRAME]
> media_type=video
> key_frame=0
> pkt_pts=24958
> pkt_pts_time=24.958000
> pkt_dts=24958
> pkt_dts_time=24.958000
> best_effort_timestamp=24958
> best_effort_timestamp_time=24.958000
> pkt_duration=N/A
> pkt_duration_time=N/A
> pkt_pos=18554505
> pkt_size=25065
> width=1920
> height=1080
> pix_fmt=yuv420p
> sample_aspect_ratio=1:1
> pict_type=P
> coded_picture_number=0
> display_picture_number=0
> interlaced_frame=0
> top_field_first=0
> repeat_pict=0
> [/FRAME]
> [FRAME]
> media_type=video
> key_frame=1
> pkt_pts=24958
> pkt_pts_time=24.958000
> pkt_dts=24958
> pkt_dts_time=24.958000
> best_effort_timestamp=24958
> best_effort_timestamp_time=24.958000
> pkt_duration=N/A
> pkt_duration_time=N/A
> pkt_pos=18579594
> pkt_size=98654
> width=1920
> height=1080
> pix_fmt=yuv420p
> sample_aspect_ratio=1:1
> pict_type=I
> coded_picture_number=0
> display_picture_number=0
> interlaced_frame=0
> top_field_first=0
> repeat_pict=0
> [/FRAME]

My guess is that it could be related to the fact that there is no
frame/packet duration in the first frame. The frame duration can only
be guessed from the next frame (it will be pts2-pts1), but that
information is lost when segmenting the file.

I think you should file an issue on trac, possibly providing a sample
and a reproducible use-case.