Re: [PATCH v3 07/10] media: uapi: Add generic 8-bit metadata format definitions

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Laurent,

On Thu, Sep 07, 2023 at 11:47:12AM +0300, Laurent Pinchart wrote:
> > > > > +V4L2_META_FMT_GENERIC_8
> > > > > +-----------------------
> > > > > +
> > > > > +The V4L2_META_FMT_GENERIC_8 format is a plain 8-bit metadata format.
> > > > > +
> > > > > +This format is also used on CSI-2 on both 8 bits per sample as well as on
> > > > 
> > > > s/also on/by/
> > > > 
> > > > I would also mention "MIPI CCS" instead of "CSI-2".
> > > 
> > > If CCS were to be mentioned here, then all uses of this format should be
> > > included as well.
> > > 
> > > > > +16 bits per sample when two bytes of metadata are packed into one sample.
> > > > 
> > > > "bits per sample" is very ill-defined for metadata, as there's no
> > > > sample. I would write "for both the RAW8 packing and the 2 bytes RAW16
> > > > packing" or something similar.
> > > > 
> > > > Similar comments for below.
> > > 
> > > From CSI-2 bus point of view there's no difference between pixel and
> > > embedded data when it comes to encoding that data. "Sample" is the next
> > > best term beyond "pixel", as the bus can carry samples that may or may not
> > > be pixel data. But I'm fine with changing the wording if you think it makes
> > > it more understandable.
> > 
> > I'll use "data unit" in v4.
> 
> Please define the term :-)

To the glossary, how about this:

    Data unit

	Unit of data transported by a bus. On parallel buses, this is
	called a sample while on serial buses the data unit is logical. If
	the data unit is image data, it may also be called a pixel.

-- 
Sakari Ailus