[FFmpeg-cvslog] avcodec/av1dec: fix loading PrevGmParams for frames with primary_ref_frame none

[James Almer]

ffmpeg | branch: master | James Almer <jamrial at gmail.com> | Wed Oct 28 11:23:44 2020 -0300| [fec1b4738f351260b12cc88b79e95b39308190ba] | committer: James Almer

avcodec/av1dec: fix loading PrevGmParams for frames with primary_ref_frame none

Reviewed-by: Mark Thompson <sw at jkqxz.net>
Signed-off-by: James Almer <jamrial at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fec1b4738f351260b12cc88b79e95b39308190ba
---

 libavcodec/av1dec.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/libavcodec/av1dec.c b/libavcodec/av1dec.c
index e01ac6641a..9566f7aa7d 100644
--- a/libavcodec/av1dec.c
+++ b/libavcodec/av1dec.c
@@ -57,13 +57,22 @@ static void read_global_param(AV1DecContext *s, int type, int ref, int idx)
 {
     uint8_t primary_frame, prev_frame;
     uint32_t abs_bits, prec_bits, round, prec_diff, sub, mx;
-    int32_t r;
+    int32_t r, prev_gm_param;
 
     primary_frame = s->raw_frame_header->primary_ref_frame;
     prev_frame = s->raw_frame_header->ref_frame_idx[primary_frame];
     abs_bits = AV1_GM_ABS_ALPHA_BITS;
     prec_bits = AV1_GM_ALPHA_PREC_BITS;
 
+    /* setup_past_independence() sets PrevGmParams to default values. We can
+     * simply point to the current's frame gm_params as they will be initialized
+     * with defaults at this point.
+     */
+    if (s->raw_frame_header->primary_ref_frame == AV1_PRIMARY_REF_NONE)
+        prev_gm_param = s->cur_frame.gm_params[ref][idx];
+    else
+        prev_gm_param = s->ref[prev_frame].gm_params[ref][idx];
+
     if (idx < 2) {
         if (type == AV1_WARP_MODEL_TRANSLATION) {
             abs_bits = AV1_GM_ABS_TRANS_ONLY_BITS -
@@ -79,7 +88,7 @@ static void read_global_param(AV1DecContext *s, int type, int ref, int idx)
     prec_diff = AV1_WARPEDMODEL_PREC_BITS - prec_bits;
     sub = (idx % 3) == 2 ? (1 << prec_bits) : 0;
     mx = 1 << abs_bits;
-    r = (s->ref[prev_frame].gm_params[ref][idx] >> prec_diff) - sub;
+    r = (prev_gm_param >> prec_diff) - sub;
 
     s->cur_frame.gm_params[ref][idx] =
         (decode_signed_subexp_with_ref(s->raw_frame_header->gm_params[ref][idx],