Video merging sinking issue

[elbysam]

Hi all,

We are trying to merge couple of videos.

Using code { ffmpeg -i input.flv -qscale:v 1 -y output.mpg }
then an issue occurred in audio / Video Sinking. ie the lips sink is not correct.

[cehoyos]

To make this a valid ticket, please provide the command line you are using together with the complete, uncut console output.
And please consider providing a sample that allows to reproduce the problem.

[elbysam]

input file 1st

[elbysam]

Input File 2

[elbysam]

Hi all,
We are trying to merge couple of videos.
Using code { ffmpeg -i input1.flv -qscale:v 1 -y output1.mpg }

{ ffmpeg -i input2.flv -qscale:v 1 -y output2.mpg }

for join videos using

{ cat output1.mpg output2.mpg > indeterminate_all.mpg }

We got complete output using following code

{ ffmpeg -i indeterminate_all.mpg -qscale:v 2 completeoutput.avi }

then an issue occurred in audio / Video Sinking. ie the lips sink is not correct.

[cehoyos]

I believe this is a duplicate of ticket #1555 (and some issues on roundup), not a regression afaict.
Reproducible with:
$ ffmpeg -i TestOrginal1.flv -qscale 2 out1.avi

Works fine with -async 1:
$ ffmpeg -async 1 -i TestOrginal1.flv -qscale 2 out1async1.avi

The concatenation works here for example with the following command line:
$ ffmpeg -async 1 -f concat -i concat.txt -qscale 2 outdemuxer.avi

[cehoyos]

Here is another alternative (using the concat filter) that allows to concatenate the files and keep A/V sync (thanks to Clément Bœsch for the example):

$ ffmpeg -i TestOrginal1.flv -i TestOrginal2.flv -filter_complex '[0:0][0:1][1:0][1:1]concat=v=1:a=1[v],aresample=async=1[a]' -map [v] -map [a] -qscale 2 outfilter.avi

Or an equivalent shorter command line:

$ ffmpeg -i TestOrginal1.flv -i TestOrginal2.flv -filter_complex 'concat=a=1[v],aresample=async=1' -map [v] -qscale 2 outfiltershort.avi