Transcoding Using a Ton of CPU

[bigverm23 2]

trying to understand why CPU is so high when transcoding is set for GPU

 

Ubuntu 19

GTX 1060

 

 

 

 

ffmpeg.txt

hardware.txt

server.txt

[Luke 42077]

Hi, sometimes the cpu will still be involved. I notice this example is burning in subtitles. That is a very expensive process. Try turning off the subtitles and then you should see much better performance. Please let us know if this helps. Thanks.

[bigverm23 2]

So I have subtitle mode set to no subtitles and allow subtitle extraction on the fly....where else would I turn it off?

 

 

Edited April 30, 2019 by bigverm23

[Luke 42077]

My mistake, this one isn't burning in subtitles, but there will still be some CPU involved. @sodtworkz may have more insight.

[Luke 42077]

@@softworkz

[bigverm23 2]

yeah, I would be comfortable with a little CPU usage, but if the GPU is doing all of the heavy lifting in this case, I wouldnt suspect the CPU would be running at over 50% for the duration for the transcode.  I am willing to provide more information to investigate further.

 

I should add this is still a new Ubuntu 19 install so its very possible I'm missing a package or something on my server as well.

[softworkz 5066]

The source file is 10bit (HDR). The GPU cannot convert this to normal colors, that's why all video data is copied back to system memory and them it is color-converted and scaled by the CPU, then the resulting data is copied back to the GPU for encoding.

 

With normal colored videos, you will probably see very different results.

[bigverm23 2]

The source file is 10bit (HDR). The GPU cannot convert this to normal colors, that's why all video data is copied back to system memory and them it is color-converted and scaled by the CPU, then the resulting data is copied back to the GPU for encoding.

 

With normal colored videos, you will probably see very different results.

 

thank you for the quick response, however, I am not sure I am satisfied with this answer.  It may be my lack of knowledge in the matter, but this GPU supports decoding for H.265 (HEVC) 4:2:0 up to 12bit.

 

On my previous server build, which was an intel chip and board, the GPU handled 10bit HDR transcodes without issue and never stressed the CPU.  Now that I'm running and AMD build this seems to have become an issue...