On Mon, 2018-08-27 at 09:47 +0200, Paul Kocialkowski wrote:
> Hi,
>
> On Wed, 2018-08-22 at 13:59 -0300, Ezequiel Garcia wrote:
> > From: Shunqian Zheng <zhengsq@xxxxxxxxxxxxxx>
> >
> > Add V4L2_CID_JPEG_LUMA/CHROMA_QUANTIZATION controls to allow userspace
> > configure the JPEG quantization tables.
>
> How about having a single control for quantization?
>
> In MPEG-2/H.264/H.265, we have a single control exposed as a structure,
> which contains the tables for both luma and chroma. In the case of JPEG,
> it's not that big a deal, but for advanced video formats, it would be
> too much hassle to have one control per table.
>
> In order to keep the interface consistent, I think it'd be best to merge
> both matrices into a single control.
>
> What do you think?
>
I think it makes a lot of sense. I don't see the benefit in having luma
and chroma separated, and consistency is good.
I guess the more consistent solution would be to expose a compound
control, similar to the video quantization one.
struct v4l2_ctrl_jpeg_quantization {
__u8 luma_quantization_matrix[64];
__u8 chroma_quantization_matrix[64];
};
Thanks!
Eze
