Re: [PATCH v2 2/3] media: v4l2-core: Add support for video encoder ROI control
From: Deepa Guthyappa Madivalara
Date: Thu Jul 16 2026 - 17:57:49 EST
On 7/15/2026 1:32 AM, Hans Verkuil wrote:
On 14/07/2026 21:00, Deepa Guthyappa Madivalara wrote:
Add necessary support for controls V4L2_CID_MPEG_VIDEO_ROI_MB_DELTA_QPWhy is this new define needed? I think you can just use ROUND_TO_RANGE.
and V4L2_CID_MPEG_VIDEO_ROI_MB_SIZE.
Signed-off-by: Deepa Guthyappa Madivalara <deepa.madivalara@xxxxxxxxxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-ctrls-api.c | 1 +
drivers/media/v4l2-core/v4l2-ctrls-core.c | 40 +++++++++++++++++++++++++++++--
drivers/media/v4l2-core/v4l2-ctrls-defs.c | 10 ++++++++
include/media/v4l2-ctrls.h | 3 ++-
4 files changed, 51 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-api.c b/drivers/media/v4l2-core/v4l2-ctrls-api.c
index 93d8d4012d0f4fef004e417d0aee2ae44b1b30bd..7d41cfd7378baaa929d4da0266c45f731bb54285 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-api.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-api.c
@@ -980,6 +980,7 @@ int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
case V4L2_CTRL_TYPE_U8:
case V4L2_CTRL_TYPE_U16:
case V4L2_CTRL_TYPE_U32:
+ case V4L2_CTRL_TYPE_S8:
if (ctrl->is_array)
return -EINVAL;
ret = check_range(ctrl->type, min, max, step, def);
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
index ba047d7d86010bf0cf8f8fbf2dc343883d6bdae0..15b69dce0127e7c8546c2d23ae5458ace10301a0 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
@@ -287,6 +287,14 @@ static void __v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
memset(ptr.p_u32 + from_idx, 0, elems * sizeof(u32));
}
break;
+ case V4L2_CTRL_TYPE_S8:
+ if (value) {
+ for (i = from_idx; i < tot_elems; i++)
+ ptr.p_s8[i] = value;
+ } else {
+ memset(ptr.p_s8 + from_idx, 0, elems * sizeof(s8));
+ }
+ break;
default:
for (i = from_idx; i < tot_elems; i++) {
switch (which) {
@@ -367,6 +375,9 @@ void v4l2_ctrl_type_op_log(const struct v4l2_ctrl *ctrl)
case V4L2_CTRL_TYPE_U32:
pr_cont("%u", (unsigned)*ptr.p_u32);
break;
+ case V4L2_CTRL_TYPE_S8:
+ pr_cont("%d", *ptr.p_s8);
+ break;
case V4L2_CTRL_TYPE_AREA:
pr_cont("%ux%u", ptr.p_area->width, ptr.p_area->height);
break;
@@ -481,6 +492,21 @@ EXPORT_SYMBOL(v4l2_ctrl_type_op_log);
0; \
})
+#define ROUND_TO_RANGE_SIGNED(val, offset_type, ctrl) \
+({ \
+ offset_type offset; \
+ if ((ctrl)->maximum >= 0 && \
+ val >= (ctrl)->maximum - (s32)((ctrl)->step / 2)) \
+ val = (ctrl)->maximum; \
+ else \
+ val += (s32)((ctrl)->step / 2); \
+ val = clamp_t(typeof(val), val, \
+ (ctrl)->minimum, (ctrl)->maximum); \
+ offset = (val) - (ctrl)->minimum; \
+ offset = (ctrl)->step * (offset / (s32)(ctrl)->step); \
+ val = (ctrl)->minimum + offset; \
+})
Regards,
Hans
Agreed. Works the same for negative s8 values. I calculated this wrong way.
Will revert the change in v3.
+
/* Validate a new control */
#define zero_padding(s) \
@@ -1365,6 +1391,8 @@ static int std_validate_compound(const struct v4l2_ctrl *ctrl, u32 idx,
return -EINVAL;
break;
+ case V4L2_CID_MPEG_VIDEO_ROI_MB_DELTA_QP:
+ break;
default:
return -EINVAL;
}
@@ -1378,6 +1406,7 @@ static int std_validate_elem(const struct v4l2_ctrl *ctrl, u32 idx,
size_t len;
u64 offset;
s64 val;
+ s32 tmp;
switch ((u32)ctrl->type) {
case V4L2_CTRL_TYPE_INTEGER:
@@ -1403,7 +1432,11 @@ static int std_validate_elem(const struct v4l2_ctrl *ctrl, u32 idx,
return ROUND_TO_RANGE(ptr.p_u16[idx], u16, ctrl);
case V4L2_CTRL_TYPE_U32:
return ROUND_TO_RANGE(ptr.p_u32[idx], u32, ctrl);
-
+ case V4L2_CTRL_TYPE_S8:
+ tmp = ptr.p_s8[idx];
+ ROUND_TO_RANGE_SIGNED(tmp, s32, ctrl);
+ ptr.p_s8[idx] = (s8)tmp;
+ return 0;
case V4L2_CTRL_TYPE_BOOLEAN:
ptr.p_s32[idx] = !!ptr.p_s32[idx];
return 0;
@@ -1556,6 +1589,7 @@ void cur_to_new(struct v4l2_ctrl *ctrl)
return;
if (ctrl->is_dyn_array)
ctrl->new_elems = ctrl->elems;
+
ptr_to_ptr(ctrl, ctrl->p_cur, ctrl->p_new, ctrl->new_elems);
}
@@ -1998,6 +2032,9 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
case V4L2_CTRL_TYPE_U32:
elem_size = sizeof(u32);
break;
+ case V4L2_CTRL_TYPE_S8:
+ elem_size = sizeof(s8);
+ break;
case V4L2_CTRL_TYPE_MPEG2_SEQUENCE:
elem_size = sizeof(struct v4l2_ctrl_mpeg2_sequence);
break;
@@ -2215,7 +2252,6 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
if (flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX) {
void *ptr = ctrl->p_def.p;
-
if (p_min.p_const) {
ptr += elem_size;
ctrl->p_min.p = ptr;
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
index e062f2088490470c42d6c579ff7675be454a29b0..8f895060799ea13443143edd398dfb97f4ba0085 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
@@ -974,6 +974,8 @@ const char *v4l2_ctrl_get_name(u32 id)
case V4L2_CID_MPEG_VIDEO_AVERAGE_QP: return "Average QP Value";
case V4L2_CID_FWHT_I_FRAME_QP: return "FWHT I-Frame QP Value";
case V4L2_CID_FWHT_P_FRAME_QP: return "FWHT P-Frame QP Value";
+ case V4L2_CID_MPEG_VIDEO_ROI_MB_DELTA_QP: return "Encoder ROI MB Delta QP";
+ case V4L2_CID_MPEG_VIDEO_ROI_MB_SIZE: return "Encoder ROI MB Size";
/* VPX controls */
case V4L2_CID_MPEG_VIDEO_VPX_NUM_PARTITIONS: return "VPX Number of Partitions";
@@ -1622,6 +1624,14 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
case V4L2_CID_COLORIMETRY_HDR10_MASTERING_DISPLAY:
*type = V4L2_CTRL_TYPE_HDR10_MASTERING_DISPLAY;
break;
+ case V4L2_CID_MPEG_VIDEO_ROI_MB_DELTA_QP:
+ *type = V4L2_CTRL_TYPE_S8;
+ *flags |= V4L2_CTRL_FLAG_DYNAMIC_ARRAY;
+ break;
+ case V4L2_CID_MPEG_VIDEO_ROI_MB_SIZE:
+ *type = V4L2_CTRL_TYPE_U8;
+ *flags |= V4L2_CTRL_FLAG_READ_ONLY;
+ break;
default:
*type = V4L2_CTRL_TYPE_INTEGER;
break;
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index a1806ddbc797efa52e83cd3f685ef70d5b5483d2..9a68a3555e349f1e55aa01af5c10f08201d62bae 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -27,6 +27,7 @@ struct video_device;
/**
* union v4l2_ctrl_ptr - A pointer to a control value.
+ * @p_s8: Pointer to a 8-bit signed value.
* @p_s32: Pointer to a 32-bit signed value.
* @p_s64: Pointer to a 64-bit signed value.
* @p_u8: Pointer to a 8-bit unsigned value.
@@ -61,10 +62,10 @@ struct video_device;
* @p_const: Pointer to a constant compound value.
*/
union v4l2_ctrl_ptr {
+ s8 *p_s8;
s32 *p_s32;
s64 *p_s64;
u8 *p_u8;
- s8 *p_s8;
u16 *p_u16;
u32 *p_u32;
char *p_char;