Nicolas, can you take a look at this with your codec knowledge?
Some other review comments below:
On 15/10/2020 13:05, Dikshita Agarwal wrote:
> This control indicates the priority id to be applied
> to base layer.
>
> Signed-off-by: Dikshita Agarwal <diksh...@codeaurora.org>
> ---
> Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 9 +++++++++
> drivers/media/v4l2-core/v4l2-ctrls.c | 1 +
> include/uapi/linux/v4l2-controls.h | 1 +
> 3 files changed, 11 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> index 6e9240a..aac1ea3 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> @@ -4407,3 +4407,12 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
> to the LTR index max LTR count-1.
> This is applicable to H264 and HEVC encoder and can be applied using
> request api.
> +
> +``V4L2_CID_MPEG_VIDEO_BASELAYER_PRIORITYID (integer)``
I'd add a_ before the ID, so: V4L2_CID_MPEG_VIDEO_BASELAYER_PRIORITY_ID.
> + Specifies a priority identifier for the NAL unit,
> + which will be applied to base layer.
> + By default this value is set to 0 for base layer.
> + And the next layer will have priority ID assigned as 1,2,3 and so on.
> + Video encode can't decide the priority id to be applied to a layer
> + so this has to come from client.
> + Valid Range: from 0 to 63
I'm slightly rephrasing the text above:
Specifies a priority identifier for the NAL unit, which will be applied
to
the base layer. By default this value is set to 0 for the base layer,
and the next layer will have the priority ID assigned as 1, 2, 3 and so
on.
The video encoder can't decide the priority id to be applied to a layer,
so this has to come from client.
Valid Range: from 0 to 63.
For which codecs is this applicable? H264 and HEVC? That should be stated. If
you
have a reference to the corresponding sections that describe this, then that
would
be nice to add.
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c
> b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 046198f..c973058 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -952,6 +952,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> case V4L2_CID_MPEG_VIDEO_LTR_COUNT: return "LTR
> Count";
> case V4L2_CID_MPEG_VIDEO_FRAME_LTR_INDEX: return "Mark
> LTR frame index";
> case V4L2_CID_MPEG_VIDEO_USE_LTR_FRAME: return "Use LTR
> Frame";
> + case V4L2_CID_MPEG_VIDEO_BASELAYER_PRIORITYID: return "Base
> Layer Priority ID";
> case V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS: return "MPEG-2
> Slice Parameters";
> case V4L2_CID_MPEG_VIDEO_MPEG2_QUANTIZATION: return "MPEG-2
> Quantization Matrices";
> case V4L2_CID_MPEG_VIDEO_FWHT_PARAMS: return "FWHT
> Stateless Parameters";
> diff --git a/include/uapi/linux/v4l2-controls.h
> b/include/uapi/linux/v4l2-controls.h
> index 3801372..433e119 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -418,6 +418,7 @@ enum v4l2_mpeg_video_multi_slice_mode {
> #define V4L2_CID_MPEG_VIDEO_LTR_COUNT
> (V4L2_CID_MPEG_BASE+230)
> #define V4L2_CID_MPEG_VIDEO_FRAME_LTR_INDEX
> (V4L2_CID_MPEG_BASE+231)
> #define V4L2_CID_MPEG_VIDEO_USE_LTR_FRAME
> (V4L2_CID_MPEG_BASE+232)
> +#define V4L2_CID_MPEG_VIDEO_BASELAYER_PRIORITYID
> (V4L2_CID_MPEG_BASE+233)
>
> /* CIDs for the MPEG-2 Part 2 (H.262) codec */
> #define V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL
> (V4L2_CID_MPEG_BASE+270)
>
Regards,
Hans
