[FFmpeg-trac] #3433(ffmpeg:new): using "shortest" results in mismatched audio and video lengths

FFmpeg trac at avcodec.org
Mon Mar 3 20:23:14 CET 2014

#3433: using "shortest" results in mismatched audio and video lengths
             Reporter:  mjmvisser  |                     Type:  defect
               Status:  new        |                 Priority:  normal
            Component:  ffmpeg     |                  Version:  git-master
             Keywords:  shortest   |               Blocked By:
             Blocking:             |  Reproduced by developer:  0
Analyzed by developer:  0          |
 Summary of the bug:

 "-shortest" does not add trim/atrim filters, so the length of each output
 stream will be a multiple of sample size. In the given example, the video
 is exactly 1s, but the resulting output is 1.02s. If "-t 1.000" is passed
 instead of "-shortest", the resulting output is exactly 1s.

 The difference is that using "-t" adds trim/atrim filters, so the last
 frame->nb_samples encoded will be truncated to fit the given duration.

 How to reproduce:
 % ffmpeg -y -probesize 500000 -f image2 -r 25 -i colorbars.%04d.png -i
 100Hz_44100Hz_16bit_05sec.wav -shortest -c:v png -c:a pcm_s16le -q:v 1 -2
 -f mov colorbars.mov

 Note that input streams have durations of 5s and 1s.

 % ffprobe colorbars.mov

 Note that the output stream has a duration of 1.02s.

 ffmpeg version N-60960-gf3eef02
 built on Feb 28 2014 10:31:20

Ticket URL: <https://trac.ffmpeg.org/ticket/3433>
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