[PATCH 01/14] media: h264: Add a more generic reflist builder init
Paul Kocialkowski
paulk at sys-base.io
Fri May 22 03:16:40 PDT 2026
This should become part of a larger reflist builder rework.
Signed-off-by: Paul Kocialkowski <paulk at sys-base.io>
---
drivers/media/v4l2-core/v4l2-h264.c | 69 +++++++++++++++++++++++++++++
include/media/v4l2-h264.h | 7 +++
2 files changed, 76 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-h264.c b/drivers/media/v4l2-core/v4l2-h264.c
index c00197d095e7..4e5a177ca2c7 100644
--- a/drivers/media/v4l2-core/v4l2-h264.c
+++ b/drivers/media/v4l2-core/v4l2-h264.c
@@ -105,6 +105,75 @@ v4l2_h264_init_reflist_builder(struct v4l2_h264_reflist_builder *b,
}
EXPORT_SYMBOL_GPL(v4l2_h264_init_reflist_builder);
+void
+v4l2_h264_init_reflist_builder_gen(struct v4l2_h264_reflist_builder *b,
+ const struct v4l2_ctrl_h264_sps *sps,
+ const struct v4l2_h264_dpb_entry dpb[V4L2_H264_NUM_DPB_ENTRIES],
+ unsigned int pic_order_count, unsigned int frame_num, unsigned int fields)
+{
+ int cur_frame_num, max_frame_num;
+ unsigned int i;
+
+ max_frame_num = 1 << (sps->log2_max_frame_num_minus4 + 4);
+ cur_frame_num = frame_num;
+
+ memset(b, 0, sizeof(*b));
+ b->cur_pic_order_count = pic_order_count;
+ b->cur_pic_fields = fields;
+
+ for (i = 0; i < V4L2_H264_NUM_DPB_ENTRIES; i++) {
+ if (!(dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
+ continue;
+
+ if (dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_LONG_TERM)
+ b->refs[i].longterm = true;
+
+ /*
+ * Handle frame_num wraparound as described in section
+ * '8.2.4.1 Decoding process for picture numbers' of the spec.
+ * For long term references, frame_num is set to
+ * long_term_frame_idx which requires no wrapping.
+ */
+ if (!b->refs[i].longterm && dpb[i].frame_num > cur_frame_num)
+ b->refs[i].frame_num = (int)dpb[i].frame_num -
+ max_frame_num;
+ else
+ b->refs[i].frame_num = dpb[i].frame_num;
+
+ b->refs[i].top_field_order_cnt = dpb[i].top_field_order_cnt;
+ b->refs[i].bottom_field_order_cnt = dpb[i].bottom_field_order_cnt;
+
+ if (b->cur_pic_fields == V4L2_H264_FRAME_REF) {
+ u8 fields = V4L2_H264_FRAME_REF;
+
+ b->unordered_reflist[b->num_valid].index = i;
+ b->unordered_reflist[b->num_valid].fields = fields;
+ b->num_valid++;
+ continue;
+ }
+
+ if (dpb[i].fields & V4L2_H264_TOP_FIELD_REF) {
+ u8 fields = V4L2_H264_TOP_FIELD_REF;
+
+ b->unordered_reflist[b->num_valid].index = i;
+ b->unordered_reflist[b->num_valid].fields = fields;
+ b->num_valid++;
+ }
+
+ if (dpb[i].fields & V4L2_H264_BOTTOM_FIELD_REF) {
+ u8 fields = V4L2_H264_BOTTOM_FIELD_REF;
+
+ b->unordered_reflist[b->num_valid].index = i;
+ b->unordered_reflist[b->num_valid].fields = fields;
+ b->num_valid++;
+ }
+ }
+
+ for (i = b->num_valid; i < ARRAY_SIZE(b->unordered_reflist); i++)
+ b->unordered_reflist[i].index = i;
+}
+EXPORT_SYMBOL_GPL(v4l2_h264_init_reflist_builder_gen);
+
static s32 v4l2_h264_get_poc(const struct v4l2_h264_reflist_builder *b,
const struct v4l2_h264_reference *ref)
{
diff --git a/include/media/v4l2-h264.h b/include/media/v4l2-h264.h
index 0d9eaa956123..1833c0556963 100644
--- a/include/media/v4l2-h264.h
+++ b/include/media/v4l2-h264.h
@@ -42,6 +42,7 @@ struct v4l2_h264_reflist_builder {
u8 cur_pic_fields;
struct v4l2_h264_reference unordered_reflist[V4L2_H264_REF_LIST_LEN];
+ /* FIXME: confusing with valid flag (active is checked). Proper terminology is "used" */
u8 num_valid;
};
@@ -51,6 +52,12 @@ v4l2_h264_init_reflist_builder(struct v4l2_h264_reflist_builder *b,
const struct v4l2_ctrl_h264_sps *sps,
const struct v4l2_h264_dpb_entry dpb[V4L2_H264_NUM_DPB_ENTRIES]);
+void
+v4l2_h264_init_reflist_builder_gen(struct v4l2_h264_reflist_builder *b,
+ const struct v4l2_ctrl_h264_sps *sps,
+ const struct v4l2_h264_dpb_entry dpb[V4L2_H264_NUM_DPB_ENTRIES],
+ unsigned int pic_order_count, unsigned int frame_num, unsigned int fields);
+
/**
* v4l2_h264_build_b_ref_lists() - Build the B0/B1 reference lists
*
--
2.53.0
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