media: v4l2: Reorder field reflist

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@collabora.com>
Reviewed-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

diff --git a/drivers/media/v4l2-core/v4l2-h264.c b/drivers/media/v4l2-core/v4l2-h264.c
index fe215035d9e823871c8b43b8470d49673821d461..72bd64f651981da2c4647d01c4b6ebd3ce14ed9f 100644 (file)
--- 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]);