[FFmpeg-devel] [Patch] Auto Insert of hwupload_cuda filter

Philip Langdale philipl at overt.org
Wed Jul 26 12:18:06 EEST 2017

On 2017-07-25 09:41, Yogender Gupta wrote:
> Currently combining CPU and CUDA filters requires insertion of
> hwupload and download filters. I am trying to simply this by auto
> insertion of these filters. This patch is for hwupload_cuda, but I
> want to do this for hwdownload as well.
> The attached patch automatically inserts hwupload_cuda filter when it
> detects a GPU filter  after a CPU component.
> Before the patch
> ffmpeg.exe -y -i traffic_flow_1280x720_420.y4m -vf "hwupload_cuda,
> scale_npp=176:144" out.h264
> After the patch the command line works without inserting the
> hwupload_cuda filter (auto inserted by ffmpeg)
> ffmpeg.exe -y -i traffic_flow_1280x720_420.y4m -vf "scale_npp=176:144" 
> out.h264
> Thanks,
> Yogender

At various points in time, people have observed that hwupload_cuda 
should be obsolete as
the generic hwupload filter should be sufficient in combination with a 
properly implement
hwcontext (which cuda has). I don't think anyone has validated this 
properly, but that
should be step one.

With that established, auto-insertion of hwupload/download should be 
done in a generic way;
I'm not the person to say how that should be done, but I'm pretty 
confident that the
people who know this stuff (wm4, Mark Thompson, etc) would agree this is 
the preferred


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