Encoder: fix packet writing of empty sub-bands (#891, #892)

There are situations where, given a tile size, at a resolution level,
there are sub-bands with x0==x1 or y0==y1, that consequently don't have any
valid codeblocks, but the other sub-bands may be non-empty.
Given that we recycle the memory from one tile to another one, those
ghost codeblocks might be non-0 and thus candidate for packet inclusion.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/lib/openjp2/tcd.h b/src/lib/openjp2/tcd.h
index 913979a8..4f842b41 100644
--- a/src/lib/openjp2/tcd.h
+++ b/src/lib/openjp2/tcd.h
@@ -375,6 +375,12 @@ OPJ_BOOL opj_tcd_copy_tile_data(opj_tcd_t *p_tcd,
  */
 OPJ_BOOL opj_alloc_tile_component_data(opj_tcd_tilecomp_t *l_tilec);
 
+/** Returns whether a sub-band is empty (i.e. whether it has a null area)
+ * @param band Sub-band handle.
+ * @return OPJ_TRUE whether the sub-band is empty.
+ */
+OPJ_BOOL opj_tcd_is_band_empty(opj_tcd_band_t* band);
+
 /* ----------------------------------------------------------------------- */
 /*@}*/