[FFmpeg-trac] #3508(undetermined:closed): Cannot open stats file on second pass when attempting to generate multiple outputs.

[FFmpeg]

#3508: Cannot open stats file on second pass when attempting to generate multiple
outputs.
-------------------------------------+-------------------------------------
             Reporter:  ianken       |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:
              Version:  unspecified  |  undetermined
             Keywords:               |               Resolution:
             Blocking:               |  needs_more_info
Analyzed by developer:  0            |               Blocked By:
                                     |  Reproduced by developer:  0
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Comment (by ianken):

 Replying to [comment:7 cehoyos]:
 > Replying to [comment:5 cehoyos]:
 > > What's wrong with the following?
 > > {{{
 > > $ ffmpeg -y -i big_buck_bunny_720p_stereo.avi -vf
 scale=240:trunc(ow/a/2)*2 -g 48 -keyint_min 6 -vcodec mpeg4 -b:v 400k
 -pass 1 -an -f mp4 NUL -vf scale=320:trunc(ow/a/2)*2 -g 48 -keyint_min 6
 -vcodec mpeg4 -b:v 700k -pass 1 -an -f mp4 NUL
 > > $ ffmpeg -y -i big_buck_bunny_720p_stereo.avi -vf
 scale=240:trunc(ow/a/2)*2 -g 48 -keyint_min 6 -vcodec mpeg4 -b:v 400k
 -pass 2 -an -f mp4 big_buck_bunny_400.mp4 -vf scale=320:trunc(ow/a/2)*2 -g
 48 -keyint_min 6 -vcodec mpeg4 -b:v 700k -pass 2 -an -f mp4
 big_buck_bunny_700.mp4
 > > }}}
 >
 > > Note that even if your command lines would work (they may work with a
 {{{cp ffmpeg2pass-0.log ffmpeg2pass-1.log && cp ffmpeg2pass-0.log.mbtree
 ffmpeg2pass-1.log.mbtree}}} in-between), this is not how two-pass encoding
 is supposed to be used to the best of my knowledge.
 >
 > Please reopen if you believe there is a bug in FFmpeg that can be fixed.

 That works. Although it defeats the purpose of doing s single PASS1 for N
 PASS2 items.

 I'd note that executing N PASS2 runs separately after a single PASS1
 works. Hence my attempt at doing all of the PASS2 encodes in one go. Also,
 I was hoping that a single log file shared across N PASS2 encodes would
 enforce GOP structure across streams to enable smoothstreaming/HLS use.

 But I think I can work around this.

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Ticket URL: <https://trac.ffmpeg.org/ticket/3508#comment:8>
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