[FFmpeg-cvslog] lavc/vvc: Fix derivation of LmcsMaxBinIdx

[Frank Plowman]

ffmpeg | branch: master | Frank Plowman <post at frankplowman.com> | Thu Nov 28 22:17:27 2024 +0000| [499896ca2f3665d936f5892dee4a9d37b03fbea2] | committer: Nuo Mi

lavc/vvc: Fix derivation of LmcsMaxBinIdx

Per H.266 (V3) section 7.4.3.19, LmcsMaxBinIdx is set equal to
15 - lmcs_delta_max_bin_idx.  The previous code instead had it equal to
15 - lmcs_min_bin_idx.  This could cause decoder mismatches.

Signed-off-by: Frank Plowman <post at frankplowman.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=499896ca2f3665d936f5892dee4a9d37b03fbea2
---

 libavcodec/vvc/ps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/vvc/ps.c b/libavcodec/vvc/ps.c
index 14cedfd1b3..2dfa680884 100644
--- a/libavcodec/vvc/ps.c
+++ b/libavcodec/vvc/ps.c
@@ -742,7 +742,7 @@ static int lmcs_derive_lut(VVCLMCS *lmcs, const H266RawAPS *rlmcs, const H266Raw
         return AVERROR_INVALIDDATA;
 
     lmcs->min_bin_idx = rlmcs->lmcs_min_bin_idx;
-    lmcs->max_bin_idx = LMCS_MAX_BIN_SIZE - 1 - rlmcs->lmcs_min_bin_idx;
+    lmcs->max_bin_idx = LMCS_MAX_BIN_SIZE - 1 - rlmcs->lmcs_delta_max_bin_idx;
 
     memset(cw, 0, sizeof(cw));
     for (int i = lmcs->min_bin_idx; i <= lmcs->max_bin_idx; i++)