Some drivers firmwares parse by themselves slice header and need
num_delta_pocs_of_ref_rps_idx value to parse slice header
short_term_ref_pic_set().
Use one of the 4 reserved bytes to store this value without
changing the v4l2_ctrl_hevc_decode_params structure size and padding.
This value also exist in DXVA API.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
---
.../userspace-api/media/v4l/ext-ctrls-codec-stateless.rst | 7 +++++++
include/uapi/linux/v4l2-controls.h | 6 +++++-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst
index 3d8411acd5b8..92ce3e126929 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst
@@ -2923,6 +2923,13 @@ This structure contains all loop filter related parameters. See sections
- ``poc_lt_curr[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]``
- PocLtCurr as described in section 8.3.2 "Decoding process for reference
picture set": provides the index of the long term references in DPB array.
+ * - __u8
+ - ``num_delta_pocs_of_ref_rps_idx``
+ - When the short_term_ref_pic_set_sps_flag in the slice header is equal to 0,
+ it is the same than derived value NumDeltaPocs[RefRpsIdx]. It can be used to parse
+ the RPS data in slice headers instead of skipping it with @short_term_ref_pic_set_size.
+ When the value of short_term_ref_pic_set_sps_flag in the slice header is
+ equal to 1, num_delta_pocs_of_ref_rps_idx shall be set to 0.
* - struct :c:type:`v4l2_hevc_dpb_entry`
- ``dpb[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]``
- The decoded picture buffer, for meta-data about reference frames.
diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index 5e80daa4ffe0..7bf59a87a1bf 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -2385,6 +2385,9 @@ struct v4l2_ctrl_hevc_slice_params {
* @poc_st_curr_after: provides the index of the short term after references
* in DPB array
* @poc_lt_curr: provides the index of the long term references in DPB array
+ * @num_delta_pocs_of_ref_rps_idx: same as the derived value NumDeltaPocs[RefRpsIdx],
+ * can be used to parse the RPS data in slice headers
+ * instead of skipping it with @short_term_ref_pic_set_size.
* @reserved: padding field. Should be zeroed by applications.
* @dpb: the decoded picture buffer, for meta-data about reference frames
* @flags: see V4L2_HEVC_DECODE_PARAM_FLAG_{}
@@ -2400,7 +2403,8 @@ struct v4l2_ctrl_hevc_decode_params {
__u8 poc_st_curr_before[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
__u8 poc_st_curr_after[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
__u8 poc_lt_curr[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
- __u8 reserved[4];
+ __u8 num_delta_pocs_of_ref_rps_idx;
+ __u8 reserved[3];
struct v4l2_hevc_dpb_entry dpb[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
__u64 flags;
};
--
2.34.1
