On Mon, Nov 3, 2025 at 4:47 PM Mark Filipak via ffmpeg-user < [email protected]> wrote:
> Resubmitting. I had some unresolved labels. Fixed. Sorry. > > How do I make asetpts work? > > I have 4 audio files: '1a0 .flac' '2a0 .flac' '3a0 .flac' '4a0 .flac' > I make 4 new audio files: '1a0.flac' '2a0.flac' '3a0.flac' '4a0.flac' > made like this: > ffmpeg -i "1a0 .flac" -filter_complex "[0:a:0]asetpts=PTS+6006[a]" -map > "[a]" -c:a:0 flac "1a0.flac" > ffmpeg -i "2a0 .flac" -filter_complex "[0:a:0]asetpts=PTS+16016[a]" -map > "[a]" -c:a:0 flac "2a0.flac" > ffmpeg -i "3a0 .flac" -filter_complex "[0:a:0]asetpts=PTS+38038[a]" -map > "[a]" -c:a:0 flac "3a0.flac" > ffmpeg -i "4a0 .flac" -filter_complex "[0:a:0]asetpts=PTS+76076[a]" -map > "[a]" -c:a:0 flac "4a0.flac" > > I'm trying to shift audio by > '1a0 .flac' 6006 aticks = 0.125125 seconds > '2a0 .flac' 16016 aticks = 0.33366666666666666666666666666667 seconds > '3a0 .flac' 38038 aticks = 0.79245833333333333333333333333333 seconds > '4a0 .flac' 76076 aticks = 1.5849166666666666666666666666667 seconds > > The PTS additions make no difference. > > Binary comparison: > _OLD_FILE_ _NEW_FILE_ > '1a0 .flac' and '1a0.flac' are identical. > '2a0 .flac' and '2a0.flac' are identical. > '3a0 .flac' and '3a0.flac' are identical. > '4a0 .flac' and '4a0.flac' are identical. > > I add "expr=" and try again. > ffmpeg -i "1a0 .flac" -filter_complex "[0:a:0]asetpts=expr=PTS+6006[a]" > -map "[a]" -c:a:0 flac "%_JOB_%1a0.flac" > ffmpeg -i "2a0 .flac" -filter_complex "[0:a:0]asetpts=expr=PTS+16016[a]" > -map "[a]" -c:a:0 flac "%_JOB_%2a0.flac" > ffmpeg -i "3a0 .flac" -filter_complex "[0:a:0]asetpts=expr=PTS+38038[a]" > -map "[a]" -c:a:0 flac "%_JOB_%3a0.flac" > ffmpeg -i "4a0 .flac" -filter_complex "[0:a:0]asetpts=expr=PTS+76076[a]" > -map "[a]" -c:a:0 flac "%_JOB_%4a0.flac" > > The PTS additions make no difference. > > Binary comparison: > _OLD_FILE_ _NEW_FILE_ > '1a0 .flac' and '1a0.flac' are identical. > '2a0 .flac' and '2a0.flac' are identical. > '3a0 .flac' and '3a0.flac' are identical. > '4a0 .flac' and '4a0.flac' are identical. > > asetpts is doing nothing. How do I make asetpts work? Thanks. > asetpts filter works just fine. FLAC muxer/demuxer stores nowhere start_time=X of audio. So your asetpts filter does virtually nothing after exiting filtergraph and enters FLAC muxer/encoder. Besides FLAC does not store timestamps either. Alternative is to use adelay instead of asetpts to insert silence samples into output of FLAC muxer/encoder. > _______________________________________________ > ffmpeg-user mailing list -- [email protected] > To unsubscribe send an email to [email protected] > _______________________________________________ ffmpeg-user mailing list -- [email protected] To unsubscribe send an email to [email protected]
