In 7.4.3.20 of H.266 (V3), there are two similarly-named variables:
scalingMatrixDcPred and ScalingMatrixDcRec. The old code set
ScalingMatrixDcRec, rather than scalingMatrixDcPred, in the first two
branches of the conditions on scaling_list_copy_mode_flag[id] and
aps->scaling_list_pred_mode_flag[id]. This could lead to decode
mismatches in sequences with explicitly-signalled scaling lists.
Signed-off-by: Frank Plowman <p...@frankplowman.com>
---
libavcodec/vvc/ps.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/libavcodec/vvc/ps.c b/libavcodec/vvc/ps.c
index f32f1cc5a1..9bd2d01776 100644
--- a/libavcodec/vvc/ps.c
+++ b/libavcodec/vvc/ps.c
@@ -1107,17 +1107,17 @@ static void scaling_derive(VVCScalingList *sl, const
H266RawAPS *aps)
//dc
if (id >= SL_START_16x16) {
if (!aps->scaling_list_copy_mode_flag[id] &&
!aps->scaling_list_pred_mode_flag[id]) {
- sl->scaling_matrix_dc_rec[id - SL_START_16x16] = 8;
+ dc += 8;
} else if (!aps->scaling_list_pred_id_delta[id]) {
- sl->scaling_matrix_dc_rec[id - SL_START_16x16] = 16;
+ dc += 16;
} else {
const int ref_id = id - aps->scaling_list_pred_id_delta[id];
if (ref_id >= SL_START_16x16)
dc += sl->scaling_matrix_dc_rec[ref_id - SL_START_16x16];
else
dc += sl->scaling_matrix_rec[ref_id][0];
- sl->scaling_matrix_dc_rec[id - SL_START_16x16] = dc & 255;
}
+ sl->scaling_matrix_dc_rec[id - SL_START_16x16] = dc & 255;
}
//ac
--
2.47.0
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