[FFmpeg-trac] #9337(ffmpeg:new): 'atempo' didn't work unless '-map 0' was added

FFmpeg trac at avcodec.org
Thu Jul 22 18:28:17 EEST 2021

#9337: 'atempo' didn't work unless '-map 0' was added
             Reporter:  markfilipak  |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:  ffmpeg
              Version:  git-master   |               Resolution:
             Keywords:  atempo       |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
Comment (by markfilipak):

 Sorry, I guess replying to the email doesn't work. So, I'll repeat my
 reply here, now.

 Hi Gyan, Thanks.

 Actually, it's the other way around; [0:0] & [0:1] are from the graph and
 [0:3] & [0:4] are from '-map 0'. Yes, that was surprising, but it's not
 really the issue.

      Do you want 1.mkv..5.mkv?
      With the source -- link provided -- and the scripts,
      you can generate 1.mkv..5.mkv in less than a minute,
      but I'll attach them if you prefer.

 The issue is that without '-map 0' 'atempo' doesn't function. That can be
 seen by watching the last 10 seconds of 2.mkv (without '-map 0') v. the
 last 10 seconds of 3.mkv (with '-map 0').

 3.cmd fixes that -- see 3.mkv -- but the '-map 0' adds the extra tracks.

 4.mkv & 5.mkv show which tracks were added by the graph and which were
 added by '-map 0'.

 - Mark.
Ticket URL: <https://trac.ffmpeg.org/ticket/9337#comment:4>
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