[mythtv] MythTV Kernel HW GL Deinterlacer

[Piotr Oniszczuk]

> Wiadomość napisana przez Peter Bennett <pb.mythtv at gmail.com> w dniu 30.11.2018, o godz. 20:35:
> 
> I also need to figure out how to move the image directly from the decoder to the display without going through memory for mediacodec, vaapi2 and cuda. This may be key to displaying 4K video at 50 fps.

I personally believe DRM_PRIME is best option.
IMHO here we have 2 options:
a) producer (video decoder) and consumer (DRM plane) are in the same memory - so they can work on the same buffer (zero-copy)
b) producer (video decoder) and consumer (DRM plane) are in different memory (VRAM & RAM) - then DMA_BUF allows zero-cpu-load mem copy operations.

There are already patches for ffmpeg to use DRM_PRIME for transferring data from ffmpeg v4l2 m2m decoder to DRM plane:
https://github.com/ldts/FFmpeg/commits/v4l2-drm
Maybe this might be ported also to mediacodec decoder….

I have extracted all required patches for ffmpeg 4.02 to go with DRM_PRIME:
https://github.com/warpme/minimyth2/tree/master/script/lib/ffmpeg/files

I personally think in long term we should follow kodi18 route (and reuse ideas/code Lukas developing for exploiting v4l2 m2m, DRM_PRIME, etc).

pls look on v.generic overview: https://archive.fosdem.org/2018/schedule/event/kodi/