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The original v1.3 branch had: 

((int*)tiledp)[(j * tile_w) + i] = tmp / 2;
while v2 had:
((OPJ_INT32*)tiledp)[(j * tile_w) + i] = tmp >> 1;
Divide by two and a right shift operation are only equivalent when the data
is unsigned. In this case the data is signed, so the right shift operation
is incorrectly clearing the sign bit.
Patch from: Sheet Spotter
This commit is contained in:
Mathieu Malaterre 2010-10-07 17:45:04 +00:00
parent 287be4e683
commit cc01949777
1 changed files with 1 additions and 1 deletions
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2
libopenjpeg/t1.c
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@ -1264,7 +1264,7 @@ void t1_decode_cblks(
for (j = 0; j < cblk_h; ++j) { for (j = 0; j < cblk_h; ++j) {
for (i = 0; i < cblk_w; ++i) { for (i = 0; i < cblk_w; ++i) {
OPJ_INT32 tmp = datap[(j * cblk_w) + i]; OPJ_INT32 tmp = datap[(j * cblk_w) + i];
((OPJ_INT32*)tiledp)[(j * tile_w) + i] = tmp >> 1; ((OPJ_INT32*)tiledp)[(j * tile_w) + i] = tmp / 2;
} }
} }
} else { /* if (tccp->qmfbid == 0) */ } else { /* if (tccp->qmfbid == 0) */