[FFmpeg-trac] #9081(ffmpeg:new): Progress reporting regression in 4.3.x for content with large frame gaps

[FFmpeg]

#9081: Progress reporting regression in 4.3.x for content with large frame gaps
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             Reporter:  zrumford    |                    Owner:
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  ffmpeg
              Version:  git-master  |               Resolution:
             Keywords:  regression  |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
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Comment (by zrumford):

 cehoyos, thanks for looking at this quickly

 Yes. This reproduces with master. I used the 20210127 build from
 https://johnvansickle.com/ffmpeg/builds/ffmpeg-git-amd64-static.tar.xz.

 I am still getting approval from our customer to share the actual file
 that reproduces the issue. I *hope* to be able to send it.

 I found something else which points to what may be an actual root of the
 issue. I noticed that if I execute the repro command (See bottom of this
 post for command) from an ec2 instance, the machine goes unresponsive. It
 all ssh connections are "hung" and no new ones are even collected. Host
 level metrics fortunately continue to populate which allows me to see that
 as of 4.3.1.20200831, the read IO is off the charts! See the attached
 image. There are almost a million readops per minute and 40GB of reads per
 minute! Note: CPU and write are all nominal so those are not the
 bottleneck. Last note: The input file is 83MB.

 My guess is that we are doing crazy seeking behavior to try to handle this
 content!



 repro command
 :./ffmpeg -y -hide_banner  -i /root/veros/repro.mp4 -vn -map 0:a:0  -ac 2
 -c:a aac -profile:a aac_low -b:a 248750 -maxrate:a 373125
 -max_muxing_queue_size 9999  /host/panopto/scratch/1/ec9533d8-13fb-40f1
 -aa2b-acc2002563fe.m4a  -an -map 0:v:0  -vf
 fps=fps=30,scale=1656:1246,yadif=deint=1  -colorspace bt709
 -color_primaries bt709 -color_trc bt709  -pix_fmt yuv420p  -c:v libx264
 -profile:v main -level:v 4.2 -preset medium -crf 20  -x264-params
 bframes=0:scenecut=0:aud=1:cabac=0:colormatrix=bt709 -b:v 2560000
 -maxrate:v 3840000  -bufsize 11520000  -max_muxing_queue_size 9999
 /host/panopto/scratch/1/cb704e72-a038-4eb6-8e5f-acc200256400.m4v)

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Ticket URL: <https://trac.ffmpeg.org/ticket/9081#comment:2>
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