[FFmpeg-devel] [PATCH 3/5] libavcodec/jpeg2000dec.c Fixed WRITE_FRAME and tile co-ordinates:

[gautamramk at gmail.com]

From: Gautam Ramakrishnan <gautamramk at gmail.com>

libopenjpeg2000 uses ceiling division while dividing tile
co-ordinates with the sample separation. Also, corrections
were made to the WRITE_FRAME macro.
---
 libavcodec/jpeg2000dec.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index 05e85f4317..546a646668 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -978,12 +978,11 @@ static int init_tile(Jpeg2000DecoderContext *s, int tileno)
         comp->coord_o[0][1] = tile->coord[0][1];
         comp->coord_o[1][0] = tile->coord[1][0];
         comp->coord_o[1][1] = tile->coord[1][1];
-        if (compno) {
-            comp->coord_o[0][0] /= s->cdx[compno];
-            comp->coord_o[0][1] /= s->cdx[compno];
-            comp->coord_o[1][0] /= s->cdy[compno];
-            comp->coord_o[1][1] /= s->cdy[compno];
-        }
+
+        comp->coord_o[0][0] = ff_jpeg2000_ceildiv(comp->coord_o[0][0], s->cdx[compno]);
+        comp->coord_o[0][1] = ff_jpeg2000_ceildiv(comp->coord_o[0][1], s->cdx[compno]);
+        comp->coord_o[1][0] = ff_jpeg2000_ceildiv(comp->coord_o[1][0], s->cdy[compno]);
+        comp->coord_o[1][1] = ff_jpeg2000_ceildiv(comp->coord_o[1][1], s->cdy[compno]);
 
         comp->coord[0][0] = ff_jpeg2000_ceildivpow2(comp->coord_o[0][0], s->reduction_factor);
         comp->coord[0][1] = ff_jpeg2000_ceildivpow2(comp->coord_o[0][1], s->reduction_factor);
@@ -1936,18 +1935,23 @@ static inline void tile_codeblocks(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile
             float *datap     = comp->f_data;                                                      \
             int32_t *i_datap = comp->i_data;                                                      \
             int cbps         = s->cbps[compno];                                                   \
-            int w            = tile->comp[compno].coord[0][1] - s->image_offset_x;                \
+            int w            = tile->comp[compno].coord[0][1] -                                   \
+                               ff_jpeg2000_ceildiv(s->image_offset_x, s->cdx[compno]);            \
+            int h            = tile->comp[compno].coord[1][1] -                                   \
+                               ff_jpeg2000_ceildiv(s->image_offset_y, s->cdy[compno]);            \
             int plane        = 0;                                                                 \
                                                                                                   \
             if (planar)                                                                           \
                 plane = s->cdef[compno] ? s->cdef[compno]-1 : (s->ncomponents-1);                 \
                                                                                                   \
-            y    = tile->comp[compno].coord[1][0] - s->image_offset_y / s->cdy[compno];           \
+            y    = tile->comp[compno].coord[1][0] -                                               \
+                   ff_jpeg2000_ceildiv(s->image_offset_y, s->cdy[compno]);                        \
             line = (PIXEL *)picture->data[plane] + y * (picture->linesize[plane] / sizeof(PIXEL));\
-            for (; y < tile->comp[compno].coord[1][1] - s->image_offset_y; y++) {                 \
+            for (; y < h; y++) {                                                                  \
                 PIXEL *dst;                                                                       \
                                                                                                   \
-                x   = tile->comp[compno].coord[0][0] - s->image_offset_x / s->cdx[compno];        \
+                x   = tile->comp[compno].coord[0][0] -                                            \
+                      ff_jpeg2000_ceildiv(s->image_offset_x, s->cdx[compno]);                     \
                 dst = line + x * pixelsize + compno*!planar;                                      \
                                                                                                   \
                 if (codsty->transform == FF_DWT97) {                                              \
-- 
2.17.1