[FFmpeg-devel] [PATCH] avfilter: add vf_overlay_cuda

[Maximiliano Lira Del Canto]

Hi Yaroslav


First of all, thanks for your wonderful work!, works as described, I 
started to use it in another Open source project "Opencast".

Well I started to make some tests and I wrote a more comprehensive 
example in Stack Overflow of it:

https://stackoverflow.com/questions/63471028/how-to-use-the-ffmpeg-overlay-cuda-filter-to-make-a-sbs-video


Because of my exhaustive testing, I found some bugs with the filter:

- You can't use images as a lower source.

- If you try to generate an still mp4 movie (For example a blank color 
background and try to overlay it, gives you an error.

- Transparent PNG gives blurry image with artifacts when is use for an 
overlay.


Another error, that I think it comes from the GPU used. If I use a 
latest generation Quadro or Geforce RTX, the filter works without 
problems. but if I use a more older model (Quadro K6000, Kepler), it 
gives you this error:

    [overlay_cuda @ 0x72356c0] cu->cuModuleLoadData(&ctx->cu_module,
    vf_overlay_cuda_ptx) failed -> CUDA_ERROR_INVALID_PTX: a PTX JIT
    compilation failed
    [Parsed_overlay_cuda_6 @ 0x72355c0] Failed to configure output pad
    on Parsed_overlay_cuda_6

I think this goes to an issue with the Compute Capability version 
supported. The K6000 only supports up to version 3.5


If you want, I can make a more complete report on the FFMPEG bug tracker.


Best Regards

Max.