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| author | Ezequiel Garcia <ezequiel@collabora.com> | 2020-08-25 06:52:29 +0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-09-01 15:13:28 +0300 |
| commit | eb44c6c9c236b1568985816254faf520fde21776 (patch) | |
| tree | a3ddbca0d8a3cc0ab477dd9aa4c55917cbac08d3 /Documentation/userspace-api | |
| parent | cefdf805844b551e08858971e1f64e3af378d697 (diff) | |
| download | linux-eb44c6c9c236b1568985816254faf520fde21776.tar.xz | |
media: uapi: h264: Split prediction weight parameters
The prediction weight parameters are only required under
certain conditions, which depend on slice header parameters.
As specified in section 7.3.3 Slice header syntax, the prediction
weight table is present if:
((weighted_pred_flag && (slice_type == P || slice_type == SP)) || \
(weighted_bipred_idc == 1 && slice_type == B))
Given its size, it makes sense to move this table to its control,
so applications can avoid passing it if the slice doesn't specify it.
Before this change struct v4l2_ctrl_h264_slice_params was 960 bytes.
With this change, it's 188 bytes and struct v4l2_ctrl_h264_pred_weight
is 772 bytes.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Tested-by: Jonas Karlman <jonas@kwiboo.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Diffstat (limited to 'Documentation/userspace-api')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst index 2cce412f5be1..9e4421a7c6a6 100644 --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst @@ -1879,18 +1879,23 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type - - 0x00000008 - -``Prediction Weight Table`` +``V4L2_CID_MPEG_VIDEO_H264_PRED_WEIGHTS (struct)`` + Prediction weight table defined according to :ref:`h264`, + section 7.4.3.2 "Prediction Weight Table Semantics". + The prediction weight table must be passed by applications + under the conditions explained in section 7.3.3 "Slice header + syntax". - The bitstream parameters are defined according to :ref:`h264`, - section 7.4.3.2 "Prediction Weight Table Semantics". For further - documentation, refer to the above specification, unless there is - an explicit comment stating otherwise. + .. note:: + + This compound control is not yet part of the public kernel API and + it is expected to change. -.. c:type:: v4l2_h264_pred_weight_table +.. c:type:: v4l2_ctrl_h264_pred_weights .. cssclass:: longtable -.. flat-table:: struct v4l2_h264_pred_weight_table +.. flat-table:: struct v4l2_ctrl_h264_pred_weights :header-rows: 0 :stub-columns: 0 :widths: 1 1 2 |