[FFmpeg-devel] [PATCHv6 4/4] libavcodec: v4l2: add support for v4l2 mem2mem codecs

Jorge Ramirez jorge.ramirez-ortiz at linaro.org
Sun Aug 27 19:26:32 EEST 2017

On 08/25/2017 05:35 PM, wm4 wrote:
> That looks generally OK. Is there any chance a hwaccel approach would
> be possible instead? If I've learned anything about hardware decoding,
> then that hwaccel is vastly superior to vendor-implemented full stream
> decoders.

could you help me understand what would that entitle and what how would 
that be beneficial to the users?
I just dont feel I can answer that question properly...

v4l2 provides a generic API  which is what the patchset uses to perform 
encoding/decoding on any v4l2 supported hardware (it is completely 
vendor independent)

 From the layer above (libavcodec) all it needs is a way to get the 
frame information and after processing to pass it back; so in principle, 
if the hwaccel API provides that, I could just move it all to use those 
calls if you think that fits better with ffmpeg.

but I dont think I understand the benefit of changing from the ffmpeg 
encoding/decoding API to hwaccel API.

> I don't think I like the attempt of sharing the v4l helper functions
> between libavdevice and libavcodec, but I can't tell how much it helps.

ok. I am of course open to suggestions on this (I didnt see any issues 
with what the patchset provides or I would have done it differently).

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