media: v4l2-ctrl: Add base layer priority id control.

This control indicates the priority id to be applied
to base layer.

[hverkuil: renumbered V4L2_CID_MPEG_VIDEO_BASELAYER_PRIORITY_ID]
Signed-off-by: Dikshita Agarwal <dikshita@codeaurora.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst

@@ -3637,3 +3637,12 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
       - Selecting this value specifies that HEVC slices are expected
         to be prefixed by Annex B start codes. According to :ref:`hevc`
         valid start codes can be 3-bytes 0x000001 or 4-bytes 0x00000001.
+
+``V4L2_CID_MPEG_VIDEO_BASELAYER_PRIORITY_ID (integer)``
+    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.
+    This is applicable to H264 and valid Range is from 0 to 63.
+    Source Rec. ITU-T H.264 (06/2019); G.7.4.1.1, G.8.8.1.

drivers/media/v4l2-core/v4l2-ctrls.c

@@ -950,6 +950,7 @@ const char *v4l2_ctrl_get_name(u32 id)
 	case V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE:		return "Vertical MV Search Range";
 	case V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER:		return "Repeat Sequence Header";
 	case V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME:		return "Force Key Frame";
+	case V4L2_CID_MPEG_VIDEO_BASELAYER_PRIORITY_ID:		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_FWHT_I_FRAME_QP:				return "FWHT I-Frame QP Value";

include/uapi/linux/v4l2-controls.h

@@ -427,6 +427,7 @@ enum v4l2_mpeg_video_multi_slice_mode {
 #define V4L2_CID_MPEG_VIDEO_MV_H_SEARCH_RANGE		(V4L2_CID_CODEC_BASE+227)
 #define V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE		(V4L2_CID_CODEC_BASE+228)
 #define V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME		(V4L2_CID_CODEC_BASE+229)
+#define V4L2_CID_MPEG_VIDEO_BASELAYER_PRIORITY_ID	(V4L2_CID_CODEC_BASE+230)
 
 /* CIDs for the MPEG-2 Part 2 (H.262) codec */
 #define V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL			(V4L2_CID_CODEC_BASE+270)