Re: [RFC] V4L2 unified low-level decoder API

Le vendredi 04 novembre 2016 à 14:55 +0100, Hugues FRUCHET a écrit :

quoted

quoted

I can help on H264 on a code review basis based on the functional H264
setup I have in-house and codec knowledge, but I cannot provide
implementation in a reasonable timeframe, same for VP8.



Apart of very details of each codec, we have also to state about generic
concerns such as:

-          new pixel format introduction (VP8 => VP8F, H264 => S264,
MPG2 => MG2F, MPG4 => MG4F)

I don't think it is necessary.

But currently it is done that way in all patches proposals I have seen 
so far, including rockchip:
rockchip_decoder_v4l2.c:{VAProfileH264Baseline,V4L2_PIX_FMT_H264_SLICE},

We have to state about it all together. Seems natural to me to do this 
way instead of device caps.
Doing so user knows that the driver is based on "Frame API" -so 
additional headers are required to decode input stream- and not
on "Stream API" -H264 stream can be decoded directly-.

We should probably use something else then "STREAMING" in the
capabilities instead of duplicating all the encoding formats (exception
to H264 byte-stream and H264 AVC, that also applies to streaming
drivers and there is not easy way to introduce stream-format in the API
atm). Other then that, this solution works, so it could just be
considered the right way, I just find it less elegant personally.

my two cents,
Nicolas