[Patch v7 12/12] Documention: v4l: Documentation for HEVC CIDs
From: Hans Verkuil <hidden>
Date: 2018-01-24 14:16:45
Also in:
linux-media, lkml
On 24/01/18 11:59, Smitha T Murthy wrote:
quoted hunk ↗ jump to hunk
Added V4l2 controls for HEVC encoder Signed-off-by: Smitha T Murthy <redacted> --- Documentation/media/uapi/v4l/extended-controls.rst | 400 +++++++++++++++++++++ 1 file changed, 400 insertions(+)diff --git a/Documentation/media/uapi/v4l/extended-controls.rst b/Documentation/media/uapi/v4l/extended-controls.rst index dfe49ae..46ee2bf 100644 --- a/Documentation/media/uapi/v4l/extended-controls.rst +++ b/Documentation/media/uapi/v4l/extended-controls.rst@@ -1960,6 +1960,406 @@ enum v4l2_vp8_golden_frame_sel - 1, 2 and 3 corresponding to encoder profiles 0, 1, 2 and 3. +High Efficiency Video Coding (HEVC/H.265) Control Reference +----------------------------------------------------------- + +The HEVC/H.265 controls include controls for encoding parameters of HEVC/H.265 +video codec. + + +.. _hevc-control-id: + +HEVC/H.265 Control IDs +^^^^^^^^^^^^^^^^^^^^^^ + +``V4L2_CID_MPEG_VIDEO_HEVC_MIN_QP (integer)`` + Minimum quantization parameter for HEVC. + Valid range: from 0 to 51. + +``V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP (integer)`` + Maximum quantization parameter for HEVC. + Valid range: from 0 to 51.
You probably should mention the default values for MIN_QP and MAX_QP (I assume those are 0 and 51 and are not driver specific).
+ +``V4L2_CID_MPEG_VIDEO_HEVC_I_FRAME_QP (integer)`` + Quantization parameter for an I frame for HEVC. + Valid range: from 0 to 51. + +``V4L2_CID_MPEG_VIDEO_HEVC_P_FRAME_QP (integer)`` + Quantization parameter for a P frame for HEVC. + Valid range: from 0 to 51. + +``V4L2_CID_MPEG_VIDEO_HEVC_B_FRAME_QP (integer)`` + Quantization parameter for a B frame for HEVC. + Valid range: from 0 to 51.
Sorry, this still isn't clear to me. If I set V4L2_CID_MPEG_VIDEO_HEVC_MAX_QP to 50, can I then still set V4L2_CID_MPEG_VIDEO_HEVC_B_FRAME_QP to 51? Or is 50 then the maximum? In other words, what is the relationship between these three controls and the MIN_QP/MAX_QP controls.
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_QP (boolean)``
+ HIERARCHICAL_QP allows the host to specify the quantization parameter
+ values for each temporal layer through HIERARCHICAL_QP_LAYER. This is
+ valid only if HIERARCHICAL_CODING_LAYER is greater than 1. Setting the
+ control value to 1 enables setting of the QP values for the layers.
+
+.. _v4l2-hevc-hier-coding-type:
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_TYPE``
+ (enum)
+
+enum v4l2_mpeg_video_hevc_hier_coding_type -
+ Selects the hierarchical coding type for encoding. Possible values are:
+
+.. raw:: latex
+
+ \begin{adjustbox}{width=\columnwidth}
+
+.. tabularcolumns:: |p{11.0cm}|p{10.0cm}|
+
+.. flat-table::
+ :header-rows: 0
+ :stub-columns: 0
+
+ * - ``V4L2_MPEG_VIDEO_HEVC_HIERARCHICAL_CODING_B``
+ - Use the B frame for hierarchical coding.
+ * - ``V4L2_MPEG_VIDEO_HEVC_HIERARCHICAL_CODING_P``
+ - Use the P frame for hierarchical coding.
+
+.. raw:: latex
+
+ \end{adjustbox}
+
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_LAYER (integer)``
+ Selects the hierarchical coding layer. In normal encoding
+ (non-hierarchial coding), it should be zero. Possible values are [0, 6].
+ 0 indicates HIERARCHICAL CODING LAYER 0, 1 indicates HIERARCHICAL CODING
+ LAYER 1 and so on.
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L0_QP (integer)``
+ Indicates quantization parameter for hierarchical coding layer 0.
+ For HEVC it can have a value of 0-51.
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L1_QP (integer)``
+ Indicates quantization parameter for hierarchical coding layer 1.
+ For HEVC it can have a value of 0-51.
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L2_QP (integer)``
+ Indicates quantization parameter for hierarchical coding layer 2.
+ For HEVC it can have a value of 0-51.
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L3_QP (integer)``
+ Indicates quantization parameter for hierarchical coding layer 3.
+ For HEVC it can have a value of 0-51.
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L4_QP (integer)``
+ Indicates quantization parameter for hierarchical coding layer 4.
+ For HEVC it can have a value of 0-51.
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_QP (integer)``
+ Indicates quantization parameter for hierarchical coding layer 5.
+ For HEVC it can have a value of 0-51.
+
+``V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L6_QP (integer)``
+ Indicates quantization parameter for hierarchical coding layer 6.
+ For HEVC it can have a value of 0-51.Same here: how does MIN_QP/MAX_QP influence these controls, if at all. Regards, Hans