[FFmpeg-devel] [PATCH v3 1/3] libavcodec/jpeg2000dec: Fix codeblock decode check

[gautamramk at gmail.com]

From: Gautam Ramakrishnan <gautamramk at gmail.com>

The codeblock decoder checks whether the mqc decoder
has decoded the right number of bytes. However, this
check does not account for the fact that the mqc encoder's
flush routine adds 2 bytes of data which does not have to be
read by the decoder. The check is modified to account for
this. This patch solves issue #4827
---
 libavcodec/jpeg2000dec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index f5ad8402fb..5e9e97eb6a 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -1753,9 +1753,9 @@ static int decode_cblk(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *codsty,
         pass_cnt ++;
     }
 
-    if (cblk->data + cblk->length - 2*(term_cnt < cblk->nb_terminations) != t1->mqc.bp) {
+    if (cblk->data + cblk->length - 2 > t1->mqc.bp) {
         av_log(s->avctx, AV_LOG_WARNING, "End mismatch %"PTRDIFF_SPECIFIER"\n",
-               cblk->data + cblk->length - 2*(term_cnt < cblk->nb_terminations) - t1->mqc.bp);
+               cblk->data + cblk->length - 2 - t1->mqc.bp);
     }
 
     return 1;
-- 
2.17.1