Hi Ezequiel,
On Fri, Aug 3, 2018 at 5:00 AM Ezequiel Garcia <[email protected]> wrote:
>
> From: Shunqian Zheng <[email protected]>
>
> Add V4L2_CID_JPEG_LUMA/CHROMA_QUANTIZATION controls to allow userspace
> configure the JPEG quantization tables.
>
> Signed-off-by: Shunqian Zheng <[email protected]>
> Signed-off-by: Ezequiel Garcia <[email protected]>
> ---
> Documentation/media/uapi/v4l/extended-controls.rst | 9 +++++++++
> drivers/media/v4l2-core/v4l2-ctrls.c | 4 ++++
> include/uapi/linux/v4l2-controls.h | 3 +++
> 3 files changed, 16 insertions(+)
Thanks for this series and sorry for being late with review. Please
see my comments inline.
>
> diff --git a/Documentation/media/uapi/v4l/extended-controls.rst
> b/Documentation/media/uapi/v4l/extended-controls.rst
> index 9f7312bf3365..80e26f81900b 100644
> --- a/Documentation/media/uapi/v4l/extended-controls.rst
> +++ b/Documentation/media/uapi/v4l/extended-controls.rst
> @@ -3354,6 +3354,15 @@ JPEG Control IDs
> Specify which JPEG markers are included in compressed stream. This
> control is valid only for encoders.
>
> +.. _jpeg-quant-tables-control:
> +
> +``V4L2_CID_JPEG_LUMA_QUANTIZATION (__u8 matrix)``
> + Sets the luma quantization table to be used for encoding
> + or decoding a V4L2_PIX_FMT_JPEG_RAW format buffer. This table is
> + expected to be in JPEG zigzag order, as per the JPEG specification.
Should we also specify this to be 8x8?
> +
> +``V4L2_CID_JPEG_CHROMA_QUANTIZATION (__u8 matrix)``
> + Sets the chroma quantization table.
>
nit: I guess we aff something like
"See also V4L2_CID_JPEG_LUMA_QUANTIZATION for details."
to avoid repeating the V4L2_PIX_FMT_JPEG_RAW and zigzag order bits? Or
maybe just repeating is better?
>
> .. flat-table::
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c
> b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 599c1cbff3b9..5c62c3101851 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -999,6 +999,8 @@ const char *v4l2_ctrl_get_name(u32 id)
> case V4L2_CID_JPEG_RESTART_INTERVAL: return "Restart Interval";
> case V4L2_CID_JPEG_COMPRESSION_QUALITY: return "Compression Quality";
> case V4L2_CID_JPEG_ACTIVE_MARKER: return "Active Markers";
> + case V4L2_CID_JPEG_LUMA_QUANTIZATION: return "Luminance
> Quantization Matrix";
> + case V4L2_CID_JPEG_CHROMA_QUANTIZATION: return "Chrominance
> Quantization Matrix";
>
> /* Image source controls */
> /* Keep the order of the 'case's the same as in v4l2-controls.h! */
> @@ -1284,6 +1286,8 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum
> v4l2_ctrl_type *type,
> *flags |= V4L2_CTRL_FLAG_READ_ONLY;
> break;
> case V4L2_CID_DETECT_MD_REGION_GRID:
> + case V4L2_CID_JPEG_LUMA_QUANTIZATION:
> + case V4L2_CID_JPEG_CHROMA_QUANTIZATION:
It looks like with this setup, the driver has to explicitly set dims
to { 8, 8 } and min/max to 0/255.
At least for min and max, we could set them here. For dims, i don't
see it handled in generic code, so I guess we can leave it to the
driver now and add move into generic code, if another driver shows up.
Hans, what do you think?
Best regards,
Tomasz
