[FFmpeg-user] What am I doing wrong with xfade
Cecil at decebal.nl
Sat Sep 10 19:09:28 EEST 2022
Paul B Mahol <onemda at gmail.com> writes:
> On 9/10/22, Cecil Westerhof via ffmpeg-user <ffmpeg-user at ffmpeg.org> wrote:
>> I have to concatenate about 30 videos together with xfade. Because I
>> did not mange to find a way to do that in one command I wrote a script
>> that does 1 and 2 to 1-2, 3 and 4 to 3-4, 4 and 5 to 5-6, …
>> Then 1-2 and 3-4 to 1-4, 5-6 and 7-8 to 5-8, …
>> But it seems that in every iteration the audio goes out of sync with
>> about one second.
>> Example of one of the commands:
>> nice -n 10 ionice -c3 time ffmpeg -y \
>> -i snellerDanDeWind.mkv \
>> -i deFinale.mkv \
>> -vcodec libx264 \
>> -crf 26 \
>> -acodec libmp3lame \
>> -qscale:a 9 \
>> -preset veryfast \
> Offset should be first video duration minus xfade duration.
> Assuming that audio is not longer than video.
>> DURATION : 00:02:10.083000000
But that is the case.
02:10.083000000 -> 130.083
130.083 - 4 = 126.083
Audio and video off the first file are the same.
Strangely the video of the second file is 0.44 seconds longer as the
audio. But that should not be a problem?
Senior Software Engineer
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