[FFmpeg-user] Problem with concat at the stitch point!
oliver at fromme.com
Tue Jul 23 17:18:10 CEST 2013
Colin Barnette wrote:
> I have been using ffmpeg to encode videos of gameplay recorded with FRAPS.
> I encode the files to .avi at 11000k bitrate, all with the same settings.
> I then use the concat function to stitch the files together. This usually
> is not a problem however a stitch point seems to have a problem in which
> the dithering from frame to frame gets mangled and the picture becomes
> blocky and strangely interpolated This continues for the rest of the video.
> In this instance, the problem occurs precisely at the stitch point from
> file 3 to file 4.
> Is this behavior documented? Have I been somewhat clear in my explanation?
> I really am not sure what to do about this as I have tried to re-concat
> the files to no avail!
> Any clues or help would be very appreciated!
> Here's an example of my batch script to first encode:
> ffmpeg -i s7-1.avi -b:v 11000k 7-1.avi
> ffmpeg -i s7-2.avi -b:v 11000k 7-2.avi
> ffmpeg -i s7-3.avi -b:v 11000k 7-3.avi
> ffmpeg -i s7-4.avi -b:v 11000k 7-4.avi
> And the command I use to concat:
> ffmpeg -f concat -i list.txt -c copy 7-Final.avi
> And a portion of 'list.txt':
> file '7-1.avi'
> file '7-2.avi'
> file '7-3.avi'
> file '7-4.avi'
When I concatenate files, I use a different syntax:
ffmpeg -i "concat:file1|file2|file3|file4" ...
I don't know if that makes any difference, but it might be
worth a try.
Also, it might work better to concatenate the source files
first and then encode the result to 11000 kbps, i.e.:
ffmpeg -i "concat:s7-1.avi|s7-2.avi|s7-3.avi|s7-4.avi" -b:v 11000k 7-Final.avi
Finally, please make sure that you use a reasonably recent
version of ffmpeg (the version from git head if possible).
In particular, do not use any version older than 1.2.
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