[FFmpeg-user] Troubleshooting cat'ing mpeg videos
belcampo at zonnet.nl
Wed Jul 20 22:47:36 CEST 2011
On 07/20/11 22:25, Brian Cardarella wrote:
> I have two mpg videos that I've transcoded from mp4s. Each are 10
> seconds long. When I play the transcoded mpg files individually they
> run through just fine. But when I cat them into a combined mpg the
> first one plays and when I get to the 10 second mark the 2nd one plays
> for about 2 seconds, wish playback that seems to be skipping frames
> and the audio is off. Then the video ends.
> The combined playing time should be 20 seconds as each file
> individually is 10 seconds. But the combined file only plays for 13
AFAIK it's not possible to cat individual mpeg-files to 1, and expect
them to play well.
Each individual file has time-stamps, each individual file probably has
The 'catted' file starts at 0.00 sec and after 10 secs it's reset to
If in the first part audio is 1 sec behind video, which will play fine,
because the player knows how to handle this, and the in the second part
audio is 1 sec before video, not very common but possible, the player
gets really confused about what video-frame belongs to what audio.
Demuxing video and audio of both files, then cat these elementary
streams to 1 video and 1 audio stream, transcode and mux them together
again. Hope that sync will be correct.
> If it is of any help I have pastied the output from the transocdings
> and an ffprobe of the combined mpg:
> Any help is greatly appreciated! :)
> - Brian
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> ffmpeg-user at ffmpeg.org
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