[FFmpeg-devel] [PATCH 3/3] libavcodec/jpeg2000: fix precinct coordinate calculation

[gautamramk at gmail.com]

From: Gautam Ramakrishnan <gautamramk at gmail.com>

The calculation of precinct boundaries has been
fixed. The precinct boundaries were calculated
as an offset to the band boundary, but must
instead be calculated as an offset from the
reslevel. This patch fixes #4669 and #4679.
---
 libavcodec/jpeg2000.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/jpeg2000.c b/libavcodec/jpeg2000.c
index 3f50bf9fb3..73206d17f3 100644
--- a/libavcodec/jpeg2000.c
+++ b/libavcodec/jpeg2000.c
@@ -276,11 +276,11 @@ static int init_prec(Jpeg2000Band *band,
     /* TODO: Verify with previous count of codeblocks per band */
 
     /* Compute P_x0 */
-    prec->coord[0][0] = ((band->coord[0][0] >> log2_band_prec_width) + precno % reslevel->num_precincts_x) *
+    prec->coord[0][0] = ((reslevel->coord[0][0] >> reslevel->log2_prec_width) + precno % reslevel->num_precincts_x) *
                         (1 << log2_band_prec_width);
 
     /* Compute P_y0 */
-    prec->coord[1][0] = ((band->coord[1][0] >> log2_band_prec_height) + precno / reslevel->num_precincts_x) *
+    prec->coord[1][0] = ((reslevel->coord[1][0] >> reslevel->log2_prec_height) + precno / reslevel->num_precincts_x) *
                         (1 << log2_band_prec_height);
 
     /* Compute P_x1 */
-- 
2.17.1