[FFmpeg-devel] [vf_tonemap_cuda] VERY alpha ground work- implemented only reinhard

[Felix LeClair]

Hey everyone!

Trying to wrap my mind around how to deal with cuda HW frames and how 
to implement them.

The goal of this filter once completed will be to take in a cuda frame, 
tonemap the value to a given specification using a user requested 
algorithm (mobius, hable reinhard clip etc.)

This is useful because it completes (should) outperform cpu based 
tonemapping by multiple 1-3 orders of magnitude depending on the gpu 
used for the filter.

I've based the attached filter off of the vf_scale_cuda.cu filter.

For ease of developement, I've kept everything the same including the 
name of the filter, only changing the funtion within the file. This is 
very much a bodge to facilitate development.  As such, for testing, 
this file should replace the vf_scale_cuda.cu file in 
ffmpeg/libavfilter/vf_scale_cuda.cu

FFmpeg should then be compiled as standard for cuda filters and should 
be called as you would call the standard vf_scale_cuda filter.
The command would be similar to:
	ffmpeg -y -vsync 0 -hwaccel cuda -hwaccel_output_format cuda -i 
input.mp4 -vf scale_cuda=Source_width:Source_Height -c:a copy -c:v 
h264_nvenc -b:v 5M output.mp4

The above should decode in hardware, tonemap the frame on gpu and 
re-encode in hardware at a given bitrate.

will be in the freenode soon after sending this email (going to put on 
another cup of coffee )

Thanks,

FelixCLC (felix__)

Caviat: Like all HW filters, how effective this is will depend on how 
much overhead is faced by doing a memcpy over the pcie bus to the gpu 
itself, then passing the data back once processed.




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