[FFmpeg-trac] #7674(undetermined:reopened): ffmpeg with cuvid transcoding after version 3.4.1 work unstable on heavy load CUDA card

[FFmpeg]

#7674: ffmpeg with cuvid transcoding after version 3.4.1 work unstable on heavy
load CUDA card
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             Reporter:  maxfs79      |                    Owner:
                 Type:  defect       |                   Status:  reopened
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  unspecified  |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by malakudi):

 I am sorry but the output is irrelevant. To test the issue you need to
 have at least two Quadro P5000 or two Quadro RTX 5000 on same computer, in
 order to be able to run that many multiple instances.
 Sample bash script to test the issue:
 {{{
 #!/bin/bash
 for j in `seq 0 $1` ;
 do
 for i in `seq 1 $2` ;
 do
 ffmpeg-git -nostdin -loglevel error -stats \
 -hwaccel cuvid -hwaccel_device $j -c:v h264_cuvid -surfaces 12 \
 -i input_1080i.ts \
 -vf yadif_cuda=1:-1:1,scale_npp=w=1280:h=720 \
 -c:v h264_nvenc \
 -preset fast \
 -acodec copy -f mpegts -y /dev/null &
 done
 done
 wait
 echo done
 }}}

 Sample input file can be downloaded from
 http://207.154.237.57/files/input_1080i.ts
 It is a 1080i input and we do deinterlacing. That way we can push much
 more frames on nvenc, because if for example we use a 50fps or 60fps
 input, nvdec will limit us first.

 You run it as: ./testbench.sh 1 30 where 1 is the number of GPUs-1 (if you
 have 3, you put 2 etc) and 30 is the number of concurrent sessions per
 GPU.
 Increasing the sessions above 25-30 per GPU will show the issue
 immediately. Applying above patch resolves the issue.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7674#comment:19>
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