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j2k/jpeg2000: split stepsize in float & int variables

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This is more clear and less prone to mistakes.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer
2013-05-28 22:12:34 +02:00
parent aa0d11ed0b
commit fe7136ef82
7 changed files with 26 additions and 28 deletions
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18
libavcodec/jpeg2000.c
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@@ -267,13 +267,13 @@ int ff_jpeg2000_init_component(Jpeg2000Component *comp,
int numbps;
case JPEG2000_QSTY_NONE:
/* TODO: to verify. No quantization in this case */
band->stepsize = (float) (1 << 13);
band->f_stepsize = (float) (1 << 13);
break;
case JPEG2000_QSTY_SI:
/*TODO: Compute formula to implement. */
numbps = cbps +
lut_gain[codsty->transform][bandno + (reslevelno > 0)];
band->stepsize = (float)SHL(2048 + qntsty->mant[gbandno],
band->f_stepsize = (float)SHL(2048 + qntsty->mant[gbandno],
2 + numbps - qntsty->expn[gbandno]);
break;
case JPEG2000_QSTY_SE:
@@ -286,20 +286,20 @@ int ff_jpeg2000_init_component(Jpeg2000Component *comp,
* but it works (compared to OpenJPEG). Why?
* Further investigation needed. */
gain = cbps;
band->stepsize = pow(2.0, gain - qntsty->expn[gbandno]);
band->stepsize *= (float)qntsty->mant[gbandno] / 2048.0 + 1.0;
band->f_stepsize = pow(2.0, gain - qntsty->expn[gbandno]);
band->f_stepsize *= (float)qntsty->mant[gbandno] / 2048.0 + 1.0;
break;
default:
band->stepsize = 0;
band->f_stepsize = 0;
av_log(avctx, AV_LOG_ERROR, "Unknown quantization format\n");
break;
}
/* FIXME: In openjepg code stespize = stepsize * 0.5. Why?
* If not set output of entropic decoder is not correct. */
band->stepsize *= 0.5;
/* BITEXACT computing case --> convert to int */
if (avctx->flags & CODEC_FLAG_BITEXACT)
band->stepsize = (int32_t)(band->stepsize * (1 << 16));
if (!av_codec_is_encoder(avctx->codec))
band->f_stepsize *= 0.5;
band->i_stepsize = (int32_t)(band->f_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