[FFmpeg-user] Problem with concat at the stitch point!

[Colin Barnette]

***Apologies for the double-send.. the new Gmail key shortcuts prematurely
sent this e-mail! ***

Hi all,

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!

Thanks!

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'