As per spec, the field reflist requires interleaving top and bottom
field in a specific way that does not fit inside the sort operation.
The process consist of alternating references parity, starting with
a reference of the same parity as the current picture. This
processs is done twice, once for short term references and a second
time for the long term references.
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Fricke <sebastian.fricke@xxxxxxxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-h264.c | 42 +++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-h264.c b/drivers/media/v4l2-core/v4l2-h264.c
index fe215035d9e8..72bd64f65198 100644
--- a/drivers/media/v4l2-core/v4l2-h264.c
+++ b/drivers/media/v4l2-core/v4l2-h264.c
@@ -250,6 +250,40 @@ static int v4l2_h264_b1_ref_list_cmp(const void *ptra, const void *ptrb,
return poca < pocb ? -1 : 1;
}
+/*
+ * The references need to be reordered so that references are alternating
+ * between top and bottom field references starting with the current picture
+ * parity. This has to be done for short term and long term references
+ * separately.
+ */
+static void reorder_field_reflist(const struct v4l2_h264_reflist_builder *b,
+ struct v4l2_h264_reference *reflist)
+{
+ struct v4l2_h264_reference tmplist[V4L2_H264_REF_LIST_LEN];
+ u8 lt, i = 0, j = 0, k = 0;
+
+ memcpy(tmplist, reflist, sizeof(tmplist[0]) * b->num_valid);
+
+ for (lt = 0; lt <= 1; lt++) {
+ do {
+ for (; i < b->num_valid && b->refs[tmplist[i].index].longterm == lt; i++) {
+ if (tmplist[i].fields == b->cur_pic_fields) {
+ reflist[k++] = tmplist[i++];
+ break;
+ }
+ }
+
+ for (; j < b->num_valid && b->refs[tmplist[j].index].longterm == lt; j++) {
+ if (tmplist[j].fields != b->cur_pic_fields) {
+ reflist[k++] = tmplist[j++];
+ break;
+ }
+ }
+ } while ((i < b->num_valid && b->refs[tmplist[i].index].longterm == lt) ||
+ (j < b->num_valid && b->refs[tmplist[j].index].longterm == lt));
+ }
+}
+
static char ref_type_to_char(u8 ref_type)
{
switch (ref_type) {
@@ -360,6 +394,9 @@ v4l2_h264_build_p_ref_list(const struct v4l2_h264_reflist_builder *builder,
sort_r(reflist, builder->num_valid, sizeof(*reflist),
v4l2_h264_p_ref_list_cmp, NULL, builder);
+ if (builder->cur_pic_fields != V4L2_H264_FRAME_REF)
+ reorder_field_reflist(builder, reflist);
+
print_ref_list_p(builder, reflist);
}
EXPORT_SYMBOL_GPL(v4l2_h264_build_p_ref_list);
@@ -393,6 +430,11 @@ v4l2_h264_build_b_ref_lists(const struct v4l2_h264_reflist_builder *builder,
sort_r(b1_reflist, builder->num_valid, sizeof(*b1_reflist),
v4l2_h264_b1_ref_list_cmp, NULL, builder);
+ if (builder->cur_pic_fields != V4L2_H264_FRAME_REF) {
+ reorder_field_reflist(builder, b0_reflist);
+ reorder_field_reflist(builder, b1_reflist);
+ }
+
if (builder->num_valid > 1 &&
!memcmp(b1_reflist, b0_reflist, builder->num_valid))
swap(b1_reflist[0], b1_reflist[1]);
--
2.34.3
