[PATCH 03/10] media: uapi: h264: Split prediction weight parameters

From: Ezequiel Garcia
Date: Wed Jul 15 2020 - 16:23:13 EST


The prediction weight parameters are only required under
certain conditions, which depend on slice header parameters.

The slice header syntax specifies that 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@xxxxxxxxxxxxx>
---
.../userspace-api/media/v4l/ext-ctrls-codec.rst | 14 +++++++++-----
drivers/media/v4l2-core/v4l2-ctrls.c | 6 ++++++
drivers/staging/media/sunxi/cedrus/cedrus.h | 1 +
drivers/staging/media/sunxi/cedrus/cedrus_dec.c | 2 ++
drivers/staging/media/sunxi/cedrus/cedrus_h264.c | 6 ++----
include/media/h264-ctrls.h | 5 +++--
6 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index 16bfc98ab2f6..d1695ae96700 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -1879,18 +1879,22 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
- 0x00000008
-

-``Prediction Weight Table``
-
- The bitstream parameters are defined according to :ref:`h264`,
+``V4L2_CID_MPEG_VIDEO_H264_PRED_WEIGHT (struct)``
+ Prediction weight table 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.

-.. c:type:: v4l2_h264_pred_weight_table
+ .. note::
+
+ This compound control is not yet part of the public kernel API and
+ it is expected to change.
+
+.. c:type:: v4l2_ctrl_h264_pred_weight

.. cssclass:: longtable

-.. flat-table:: struct v4l2_h264_pred_weight_table
+.. flat-table:: struct v4l2_ctrl_h264_pred_weight
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 3f3fbcd60cc6..3a8a23e34c70 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1412,6 +1412,9 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
case V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS:
*type = V4L2_CTRL_TYPE_H264_DECODE_PARAMS;
break;
+ case V4L2_CID_MPEG_VIDEO_H264_PRED_WEIGHT:
+ *type = V4L2_CTRL_TYPE_H264_PRED_WEIGHT;
+ break;
case V4L2_CID_MPEG_VIDEO_VP8_FRAME_HEADER:
*type = V4L2_CTRL_TYPE_VP8_FRAME_HEADER;
break;
@@ -2553,6 +2556,9 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
case V4L2_CTRL_TYPE_H264_DECODE_PARAMS:
elem_size = sizeof(struct v4l2_ctrl_h264_decode_params);
break;
+ case V4L2_CTRL_TYPE_H264_PRED_WEIGHT:
+ elem_size = sizeof(struct v4l2_ctrl_h264_pred_weight);
+ break;
case V4L2_CTRL_TYPE_VP8_FRAME_HEADER:
elem_size = sizeof(struct v4l2_ctrl_vp8_frame_header);
break;
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.h b/drivers/staging/media/sunxi/cedrus/cedrus.h
index 96765555ab8a..80a0ecffa384 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus.h
+++ b/drivers/staging/media/sunxi/cedrus/cedrus.h
@@ -62,6 +62,7 @@ struct cedrus_h264_run {
const struct v4l2_ctrl_h264_scaling_matrix *scaling_matrix;
const struct v4l2_ctrl_h264_slice_params *slice_params;
const struct v4l2_ctrl_h264_sps *sps;
+ const struct v4l2_ctrl_h264_pred_weight *pred_weight;
};

struct cedrus_mpeg2_run {
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
index 58c48e4fdfe9..047f773f64f9 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
@@ -57,6 +57,8 @@ void cedrus_device_run(void *priv)
V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS);
run.h264.sps = cedrus_find_control_data(ctx,
V4L2_CID_MPEG_VIDEO_H264_SPS);
+ run.h264.pred_weight = cedrus_find_control_data(ctx,
+ V4L2_CID_MPEG_VIDEO_H264_PRED_WEIGHT);
break;

case V4L2_PIX_FMT_HEVC_SLICE:
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
index cce527bbdf86..614b1b496e40 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
@@ -256,10 +256,8 @@ static void cedrus_write_scaling_lists(struct cedrus_ctx *ctx,
static void cedrus_write_pred_weight_table(struct cedrus_ctx *ctx,
struct cedrus_run *run)
{
- const struct v4l2_ctrl_h264_slice_params *slice =
- run->h264.slice_params;
- const struct v4l2_h264_pred_weight_table *pred_weight =
- &slice->pred_weight_table;
+ const struct v4l2_ctrl_h264_pred_weight *pred_weight =
+ run->h264.pred_weight;
struct cedrus_dev *dev = ctx->dev;
int i, j, k;

diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
index bca4a9887e7e..da2ffb77b491 100644
--- a/include/media/h264-ctrls.h
+++ b/include/media/h264-ctrls.h
@@ -36,6 +36,7 @@
#define V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS (V4L2_CID_MPEG_BASE+1004)
#define V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE (V4L2_CID_MPEG_BASE+1005)
#define V4L2_CID_MPEG_VIDEO_H264_START_CODE (V4L2_CID_MPEG_BASE+1006)
+#define V4L2_CID_MPEG_VIDEO_H264_PRED_WEIGHT (V4L2_CID_MPEG_BASE+1007)

/* enum v4l2_ctrl_type type values */
#define V4L2_CTRL_TYPE_H264_SPS 0x0110
@@ -43,6 +44,7 @@
#define V4L2_CTRL_TYPE_H264_SCALING_MATRIX 0x0112
#define V4L2_CTRL_TYPE_H264_SLICE_PARAMS 0x0113
#define V4L2_CTRL_TYPE_H264_DECODE_PARAMS 0x0114
+#define V4L2_CTRL_TYPE_H264_PRED_WEIGHT 0x0115

enum v4l2_mpeg_video_h264_decode_mode {
V4L2_MPEG_VIDEO_H264_DECODE_MODE_SLICE_BASED,
@@ -125,7 +127,7 @@ struct v4l2_h264_weight_factors {
__s16 chroma_offset[32][2];
};

-struct v4l2_h264_pred_weight_table {
+struct v4l2_ctrl_h264_pred_weight {
__u16 luma_log2_weight_denom;
__u16 chroma_log2_weight_denom;
struct v4l2_h264_weight_factors weight_factors[2];
@@ -174,7 +176,6 @@ struct v4l2_ctrl_h264_slice_params {
__s32 delta_pic_order_cnt0;
__s32 delta_pic_order_cnt1;

- struct v4l2_h264_pred_weight_table pred_weight_table;
/* Size in bits of dec_ref_pic_marking() syntax element. */
__u32 dec_ref_pic_marking_bit_size;
/* Size in bits of pic order count syntax. */
--
2.27.0