[libcamera-devel] [PATCH v2 1/5] libcamera: properties: ColorFilterArrangement draft property

[Jacopo Mondi]

Hi David,

On Wed, Dec 30, 2020 at 08:59:31AM +0100, Jacopo Mondi wrote:
> Hi David,
>
> On Tue, Dec 29, 2020 at 10:32:21PM +0000, David Plowman wrote:
> > Hi Jacopo
> >
> > Thanks for the reply!
> >
> > On Tue, 29 Dec 2020 at 10:26, Jacopo Mondi <jacopo at jmondi.org> wrote:
> > >
> > > Hi David,
> > >
> > > On Tue, Dec 29, 2020 at 09:25:14AM +0000, David Plowman wrote:
> > > > Hi Jacopo
> > > >
> > > > Thanks for this patch! Just one little question - I suppose Android
> > > > (and libcamera) have some other way of signalling a monochrome
> > > > sensor... I think I might have expected to find a
> > > > "monochrome/non-Bayer" option in the list?
> > >
> > > Please bare in mind this is a draft property, whose main purpose is
> > > to temporary close the gap with Android and its definition come
> > > straight from there.
> > >
> > > This property only makes sensor for RAW sensors, although there's a
> > > more generic 'RGB' value that sounds like a catch-all for non-Bayer
> > > sensors.
> > >
> > > Simply put: non-RAW sensor won't register this property at all.
> > > When we'll un-draft the property we can discuss if that makes sense
> > > at all as a choice, or we might want to have a more generic
> > > definition.
> > >
> > > Do you perhaps have any usage for such a more generic property in mind ?
> >
> > Not especially, my thoughts on the subject are only "draft" too!  :)
> >
> > I guess my only observations are that a monochrome ("no CFA at all")
> > format would probably be useful (it's still a RAW format, though not a
>
> My bad, I always thought 'mono-chrome' as a YUV sensor with only the Y
> channel being sent out.
>
> > Bayer one). Also, that single non-RAW format (3x16-bit RGB) seems a
> > bit lonely, for example YUV422 interleaved is probably more common,
> > but I doubt we want to list all the possible pixel formats all over
> > again, we have enough of that already!
>
> I'm not sure I follow. How does a processed format like YUV422 relates
> to the sensor's color filters arrangements ?

Laurent helped clarify this to me, and yes, we probably need a
definition for monochrome going forward. I would however keep the draft
property version as close as possible to Android's definition and
expand it when un-drafting.

Thanks
  j