Verify NVENC patch

From @lars18th and @reloxx13

Linux

ffmpeg -y -vsync 0 -hwaccel cuda -hwaccel_output_format cuda \
      -f lavfi -i testsrc -t 50 \
      -vf hwupload -c:a copy -c:v h264_nvenc -b:v 4M -f null - \
      -vf hwupload -c:a copy -c:v h264_nvenc -b:v 1M -f null - \
      -vf hwupload -c:a copy -c:v h264_nvenc -b:v 8M -f null - \
      -vf hwupload -c:a copy -c:v h264_nvenc -b:v 6M -f null - \
      -vf hwupload -c:a copy -c:v h264_nvenc -b:v 5M -f null - \
      -vf hwupload -c:a copy -c:v h264_nvenc -b:v 7M -f null -

This only requires to have installed a recent ffmpeg version compiled with nvenc enabled. Almost all distributions have it now.

Windows

ffmpeg download https://www.gyan.dev/ffmpeg/builds/ffmpeg-git-full.7z

ffmpeg.exe -y -hwaccel cuda -hwaccel_output_format cuda ^
-f lavfi -i testsrc -t 50 ^
-vf hwupload -fps_mode passthrough -c:a copy -c:v h264_nvenc -b:v 4M -f null - ^
-vf hwupload -fps_mode passthrough -c:a copy -c:v h264_nvenc -b:v 1M -f null - ^
-vf hwupload -fps_mode passthrough -c:a copy -c:v h264_nvenc -b:v 8M -f null - ^
-vf hwupload -fps_mode passthrough -c:a copy -c:v h264_nvenc -b:v 6M -f null - ^
-vf hwupload -fps_mode passthrough -c:a copy -c:v h264_nvenc -b:v 5M -f null - ^
-vf hwupload -fps_mode passthrough -c:a copy -c:v h264_nvenc -b:v 7M -f null -  

Output

If you get a message like:

[h264_nvenc @ 0x55fc31535fc0] OpenEncodeSessionEx failed: out of memory (10): (no details)
Error initializing output stream 3:0 -- Error while opening encoder for output stream #3:0 - maybe incorrect parameters such as bit_rate, rate, width or height
Conversion failed!

Then the patch has failed.

But if the ffmpeg starts to work and shows:

frame=  560 fps=329 q=8.0 Lq=8.0 q=8.0 q=8.0 size=N/A time=00:00:22.40 bitrate=N/A speed=13.2x

Then... Congratulations! The patch works.