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j2k: change fixed point of stepsize to 16.16

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This seems more natural and matches jpeg2000

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2013-05-27 17:58:06 +02:00
parent 1b5cb6c00a
commit 243cc38d94
3 changed files with 4 additions and 4 deletions
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2
libavcodec/j2k.c
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@ -289,7 +289,7 @@ int ff_j2k_init_component(Jpeg2000Component *comp,
}
/* BITEXACT computing case --> convert to int */
// if (avctx->flags & CODEC_FLAG_BITEXACT)
band->stepsize = stepsize * (1 << 13);
band->stepsize = stepsize * (1 << 16);
/* computation of tbx_0, tbx_1, tby_0, tby_1
* see ISO/IEC 15444-1:2002 B.5 eq. B-15 and tbl B.1

2
libavcodec/j2kdec.c
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@ -830,7 +830,7 @@ static int decode_tile(Jpeg2000DecoderContext *s, Jpeg2000Tile *tile)
int *datap = &comp->data[(comp->coord[0][1] - comp->coord[0][0]) * (y+j) + x];
int *ptr = t1.data[j];
for (i = 0; i < (cblk->coord[0][1] - cblk->coord[0][0]); ++i) {
int tmp = ((int64_t)ptr[i]) * ((int64_t)band->stepsize) >> 13, tmp2;
int tmp = ((int64_t)ptr[i]) * ((int64_t)band->stepsize) >> 16, tmp2;
tmp2 = FFABS(tmp>>1) + (tmp&1);
datap[i] = tmp < 0 ? -tmp2 : tmp2;
}

4
libavcodec/j2kenc.c
View File

@ -802,7 +802,7 @@ static void truncpasses(Jpeg2000EncoderContext *s, Jpeg2000Tile *tile)
Jpeg2000Cblk *cblk = prec->cblk + cblkno;
cblk->ninclpasses = getcut(cblk, s->lambda,
(int64_t)dwt_norms[codsty->transform][bandpos][lev] * (int64_t)band->stepsize >> 13);
(int64_t)dwt_norms[codsty->transform][bandpos][lev] * (int64_t)band->stepsize >> 16);
}
}
}
@ -863,7 +863,7 @@ static int encode_tile(Jpeg2000EncoderContext *s, Jpeg2000Tile *tile, int tileno
int *ptr = t1.data[y-yy0];
for (x = xx0; x < xx1; x++){
*ptr = (comp->data[(comp->coord[0][1] - comp->coord[0][0]) * y + x]);
*ptr = (int64_t)*ptr * (int64_t)(8192 * 8192 / band->stepsize) >> 13 - NMSEDEC_FRACBITS;
*ptr = (int64_t)*ptr * (int64_t)(16384 * 65536 / band->stepsize) >> 14 - NMSEDEC_FRACBITS;
ptr++;
}
}