[PATCH v0 1/3] media: chips-media: wave5: Add Support for Background Detection
From: Jackson.lee
Date: Thu Mar 19 2026 - 01:32:34 EST
From: Jackson Lee <jackson.lee@xxxxxxxxxxxxxxx>
Wave5 encoder can be configured to detect a background region in a frame.
If a background region is detected, it will use less bits or skip mode to
encode that region. This can assist in lowering the video bitrate for a
given stream.
Signed-off-by: Jackson Lee <jackson.lee@xxxxxxxxxxxxxxx>
Signed-off-by: Nas Chung <nas.chung@xxxxxxxxxxxxxxx>
---
Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 5 +++++
drivers/media/platform/chips-media/wave5/wave5-hw.c | 4 +++-
drivers/media/platform/chips-media/wave5/wave5-vpu-enc.c | 7 +++++++
drivers/media/platform/chips-media/wave5/wave5-vpuapi.h | 1 +
drivers/media/v4l2-core/v4l2-ctrls-defs.c | 2 ++
include/uapi/linux/v4l2-controls.h | 2 ++
6 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index c8890cb5e00a..b992a0d5c7bf 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -605,6 +605,11 @@ enum v4l2_mpeg_video_frame_skip_mode -
chosen data limit then the frame will be skipped. Possible values
are:
+``V4L2_CID_MPEG_VIDEO_BACKGROUND_DETECTION (boolean)``
+ If enabled then, the encoder detect a background region in frame and
+ use low bits or skip mode to encode the background region.
+ If a lot of scenes are stationary or background, It may help to
+ reduce the video bitrate. Applicable to the encoder.
.. tabularcolumns:: |p{8.2cm}|p{9.3cm}|
diff --git a/drivers/media/platform/chips-media/wave5/wave5-hw.c b/drivers/media/platform/chips-media/wave5/wave5-hw.c
index 687ce6ccf3ae..c516d125f553 100644
--- a/drivers/media/platform/chips-media/wave5/wave5-hw.c
+++ b/drivers/media/platform/chips-media/wave5/wave5-hw.c
@@ -49,6 +49,7 @@
#define FASTIO_ADDRESS_MASK GENMASK(15, 0)
#define SEQ_PARAM_PROFILE_MASK GENMASK(30, 24)
+#define SEQ_BG_PARAM_REG_DATA 0x3800410
static void _wave5_print_reg_err(struct vpu_device *vpu_dev, u32 reg_fail_reason,
const char *func);
@@ -1838,7 +1839,8 @@ int wave5_vpu_enc_init_seq(struct vpu_instance *inst)
vpu_write_reg(inst->dev, W5_CMD_ENC_SEQ_RC_BIT_RATIO_LAYER_4_7, 0);
vpu_write_reg(inst->dev, W5_CMD_ENC_SEQ_ROT_PARAM, rot_mir_mode);
- vpu_write_reg(inst->dev, W5_CMD_ENC_SEQ_BG_PARAM, 0);
+ vpu_write_reg(inst->dev, W5_CMD_ENC_SEQ_BG_PARAM,
+ SEQ_BG_PARAM_REG_DATA | p_param->bg_detection);
vpu_write_reg(inst->dev, W5_CMD_ENC_SEQ_CUSTOM_LAMBDA_ADDR, 0);
vpu_write_reg(inst->dev, W5_CMD_ENC_SEQ_CONF_WIN_TOP_BOT,
p_param->conf_win_bot << 16 | p_param->conf_win_top);
diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpu-enc.c b/drivers/media/platform/chips-media/wave5/wave5-vpu-enc.c
index 7613fcdbafed..6fe01217233f 100644
--- a/drivers/media/platform/chips-media/wave5/wave5-vpu-enc.c
+++ b/drivers/media/platform/chips-media/wave5/wave5-vpu-enc.c
@@ -780,6 +780,9 @@ static int wave5_vpu_enc_s_ctrl(struct v4l2_ctrl *ctrl)
case V4L2_CID_MPEG_VIDEO_BITRATE:
inst->bit_rate = ctrl->val;
break;
+ case V4L2_CID_MPEG_VIDEO_BACKGROUND_DETECTION:
+ inst->enc_param.bg_detection = ctrl->val;
+ break;
case V4L2_CID_MPEG_VIDEO_GOP_SIZE:
inst->enc_param.avc_idr_period = ctrl->val;
break;
@@ -1205,6 +1208,7 @@ static int wave5_set_enc_openparam(struct enc_open_param *open_param,
open_param->wave_param.beta_offset_div2 = input.beta_offset_div2;
open_param->wave_param.decoding_refresh_type = input.decoding_refresh_type;
open_param->wave_param.intra_period = input.intra_period;
+ open_param->wave_param.bg_detection = input.bg_detection;
if (inst->std == W_HEVC_ENC) {
if (input.intra_period == 0) {
open_param->wave_param.decoding_refresh_type = DEC_REFRESH_TYPE_IDR;
@@ -1700,6 +1704,9 @@ static int wave5_vpu_open_enc(struct file *filp)
v4l2_ctrl_new_std(v4l2_ctrl_hdl, &wave5_vpu_enc_ctrl_ops,
V4L2_CID_MPEG_VIDEO_AU_DELIMITER,
0, 1, 1, 1);
+ v4l2_ctrl_new_std(v4l2_ctrl_hdl, &wave5_vpu_enc_ctrl_ops,
+ V4L2_CID_MPEG_VIDEO_BACKGROUND_DETECTION,
+ 0, 1, 1, 0);
v4l2_ctrl_new_std(v4l2_ctrl_hdl, &wave5_vpu_enc_ctrl_ops,
V4L2_CID_HFLIP,
0, 1, 1, 0);
diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpuapi.h b/drivers/media/platform/chips-media/wave5/wave5-vpuapi.h
index c64135769869..dc31689e0d27 100644
--- a/drivers/media/platform/chips-media/wave5/wave5-vpuapi.h
+++ b/drivers/media/platform/chips-media/wave5/wave5-vpuapi.h
@@ -570,6 +570,7 @@ struct enc_wave_param {
u32 transform8x8_enable: 1; /* enable 8x8 intra prediction and 8x8 transform */
u32 mb_level_rc_enable: 1; /* enable MB-level rate control */
u32 forced_idr_header_enable: 1; /* enable header encoding before IDR frame */
+ u32 bg_detection: 1; /* enable background detection */
};
struct enc_open_param {
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
index 551426c4cd01..e062f2088490 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
@@ -889,6 +889,7 @@ const char *v4l2_ctrl_get_name(u32 id)
case V4L2_CID_MPEG_VIDEO_DEC_DISPLAY_DELAY: return "Display Delay";
case V4L2_CID_MPEG_VIDEO_DEC_DISPLAY_DELAY_ENABLE: return "Display Delay Enable";
case V4L2_CID_MPEG_VIDEO_AU_DELIMITER: return "Generate Access Unit Delimiters";
+ case V4L2_CID_MPEG_VIDEO_BACKGROUND_DETECTION: return "Background Detection";
case V4L2_CID_MPEG_VIDEO_H263_I_FRAME_QP: return "H263 I-Frame QP Value";
case V4L2_CID_MPEG_VIDEO_H263_P_FRAME_QP: return "H263 P-Frame QP Value";
case V4L2_CID_MPEG_VIDEO_H263_B_FRAME_QP: return "H263 B-Frame QP Value";
@@ -1296,6 +1297,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
case V4L2_CID_MPEG_VIDEO_MPEG4_QPEL:
case V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER:
case V4L2_CID_MPEG_VIDEO_AU_DELIMITER:
+ case V4L2_CID_MPEG_VIDEO_BACKGROUND_DETECTION:
case V4L2_CID_WIDE_DYNAMIC_RANGE:
case V4L2_CID_IMAGE_STABILIZATION:
case V4L2_CID_RDS_RECEPTION:
diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index 68dd0c4e47b2..939f796261c0 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -464,6 +464,8 @@ enum v4l2_mpeg_video_intra_refresh_period_type {
V4L2_CID_MPEG_VIDEO_INTRA_REFRESH_PERIOD_TYPE_CYCLIC = 1,
};
+#define V4L2_CID_MPEG_VIDEO_BACKGROUND_DETECTION (V4L2_CID_CODEC_BASE+238)
+
/* CIDs for the MPEG-2 Part 2 (H.262) codec */
#define V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL (V4L2_CID_CODEC_BASE+270)
enum v4l2_mpeg_video_mpeg2_level {
--
2.43.0