[FFmpeg-trac] #6989(avcodec:closed): Hwaccel cuvid fails with “Error creating a NVDEC decoder: 1”

[FFmpeg]

#6989: Hwaccel cuvid fails with “Error creating a NVDEC decoder: 1”
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             Reporter:  tkalliom     |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:  avcodec
              Version:  git-master   |               Resolution:  invalid
             Keywords:  hwaccel      |               Blocked By:
  cuda cuvid NVDEC                   |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
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Comment (by tkalliom):

 My real use case is turning a video to a bunch of bitmaps on a file system
 for analysis, so there is actually also some color space conversion
 involved. I tried to focus on decoding and present the simplest possible
 command line to exhibit the unexpected behavior, but I guess if you
 simplify too much the examples become inane...

 With regards to the performance differences in decoding: I now compared
 CPU and NVDEC performance using the 3840x2160 HEVC sample at
 http://cloud.ultrahdtv.net/fitness-trailer-8000.mkv.

 `$ ffmpeg -i fitness-trailer-8000.mkv -f image2pipe -vcodec rawvideo -
 >/dev/null`
 Avg. 132FPS on CPU for just decoding and throwing frames away.

 `$ ffmpeg -hwaccel cuda -i fitness-trailer-8000.mkv -f image2pipe -vcodec
 rawvideo - >/dev/null`
 Avg. 107FPS on GPU – '''19%''' slower on just decoding.

 `$ ffmpeg -i fitness-trailer-8000.mkv -f image2pipe -vcodec rawvideo - >
 /tmp/frames.dat`
 Avg. 100FPS on CPU for piping to `tmpfs`.

 `ffmpeg -hwaccel cuda -i fitness-trailer-8000.mkv -f image2pipe -vcodec
 rawvideo - >frames.dat`
 Avg. 62FPS on GPU – '''37%''' slower.

 So, nvdec is decoding slower than software...

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Ticket URL: <https://trac.ffmpeg.org/ticket/6989#comment:4>
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