avcodec/jpeg2000dec: Check for mismatching per expected termination

not just at the end
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/jpeg2000dec.c

@@ -1503,6 +1503,12 @@ static int decode_cblk(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *codsty,
                 av_log(s->avctx, AV_LOG_ERROR, "Missing needed termination \n");
                 return AVERROR_INVALIDDATA;
             }
+            if (FFABS(cblk->data + cblk->data_start[term_cnt + 1] - 2 - t1->mqc.bp) > 0) {
+                av_log(s->avctx, AV_LOG_WARNING, "Mid mismatch %"PTRDIFF_SPECIFIER" in pass %d of %d\n",
+                    cblk->data + cblk->data_start[term_cnt + 1] - 2 - t1->mqc.bp,
+                    pass_cnt, cblk->npasses);
+            }
+
             ff_mqc_initdec(&t1->mqc, cblk->data + cblk->data_start[++term_cnt], coder_type == 2, 0);
         }