Re: [EXT] Re: Re: [PATCH] media: v4l: Add packed YUV444 24bpp pixel format

From: Mirela Rabulea
Date: Fri Jul 12 2019 - 09:02:30 EST


On Vi, 2019-07-12 at 11:21 +0200, paul.kocialkowski@xxxxxxxxxxx wrote:
> Hi,
>
> On Thu 11 Jul 19, 13:57, Mirela Rabulea wrote:
> >
> > On Jo, 2019-07-11 at 10:18 +0200, Paul Kocialkowski wrote:
> > >
> > > Caution: EXT Email
> > >
> > > Hi,
> > >
> > > On Wed 03 Jul 19, 18:15, Mirela Rabulea wrote:
> > > >
> > > >
> > > > The added format is V4L2_PIX_FMT_YUV24, this is a packed
> > > > YUV 4:4:4 format, with 8 bits for each component, 24 bits
> > > > per sample.
> > > >
> > > > This format is used by the i.MX 8QuadMax and i.MX
> > > > 8DualXPlus/8QuadXPlus
> > > > JPEG encoder/decoder.
> > > So this format is not aligned to 32-bit words at all and we can
> > > expect
> > > to see cases where a single 32-bit word contains data for two
> > > pixels?
> > >
> > > Nothing wrong with that, just checking whether I understood this
> > > right :)
> > >
> > Hi Paul,
> > yes, your understanding is correct.
> Out of curiosity, is the JPEG block assmiliated to (one of) the
> Hantro VPUs
> or is it a totally different and unrelated hardware block?
>
> Anyway the change looks good to me:
> Reviewed-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
>
> Cheers,
>
> Paul

Hi Paul,
thanks for taking the time to review.
The JPEG decoder is a standalone core & wrapper, not assimilated to the
VPU. It is described in the reference manual here:
https://www.nxp.com/docs/en/reference-manual/IMX8DQXPRM.pdf
in chapters "15.6.3 JPEG Decoder (JPEGDEC)" and "15.6.5 JPEG Decoder
Wrapper".
The JPEG core is from a third party, and the wrapper from NXP.

Regards,
Mirela