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| author | Michael Niedermayer <michaelni@gmx.at> | 2013-05-28 22:12:34 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2013-05-28 22:16:14 +0200 |
| commit | fe7136ef8202b19fda262ea91adc09b3367d37d7 (patch) | |
| tree | a90e7814be95420970639e8204364bf96dc6e637 /libavcodec/j2k.c | |
| parent | aa0d11ed0bdfc38f800771b1d695469ff691dd96 (diff) | |
| download | ffmpeg-fe7136ef8202b19fda262ea91adc09b3367d37d7.tar.gz | |
j2k/jpeg2000: split stepsize in float & int variables
This is more clear and less prone to mistakes.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavcodec/j2k.c')
| -rw-r--r-- | libavcodec/j2k.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/libavcodec/j2k.c b/libavcodec/j2k.c index 96fe2597cb..5a7949737b 100644 --- a/libavcodec/j2k.c +++ b/libavcodec/j2k.c @@ -248,7 +248,6 @@ int ff_j2k_init_component(Jpeg2000Component *comp, Jpeg2000Band *band = reslevel->band + bandno; int cblkno, precno; int nb_precincts; - double stepsize; /* TODO: Implementation of quantization step not finished, * see ISO/IEC 15444-1:2002 E.1 and A.6.4. */ @@ -257,13 +256,13 @@ int ff_j2k_init_component(Jpeg2000Component *comp, int numbps; case JPEG2000_QSTY_NONE: /* TODO: to verify. No quantization in this case */ - stepsize = 1; + band->f_stepsize = 1; break; case JPEG2000_QSTY_SI: /*TODO: Compute formula to implement. */ numbps = cbps + lut_gain[codsty->transform][bandno + (reslevelno > 0)]; - stepsize = SHL(2048 + qntsty->mant[gbandno], + band->f_stepsize = SHL(2048 + qntsty->mant[gbandno], 2 + numbps - qntsty->expn[gbandno]); break; case JPEG2000_QSTY_SE: @@ -276,21 +275,20 @@ int ff_j2k_init_component(Jpeg2000Component *comp, * but it works (compared to OpenJPEG). Why? * Further investigation needed. */ gain = cbps; - stepsize = pow(2.0, gain - qntsty->expn[gbandno]); - stepsize *= (qntsty->mant[gbandno] / 2048.0 + 1.0); + band->f_stepsize = pow(2.0, gain - qntsty->expn[gbandno]); + band->f_stepsize *= (qntsty->mant[gbandno] / 2048.0 + 1.0); break; default: - 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. */ if (!av_codec_is_encoder(avctx->codec)) - stepsize *= 0.5; - /* BITEXACT computing case --> convert to int */ -// if (avctx->flags & CODEC_FLAG_BITEXACT) - band->stepsize = stepsize * (1 << 16); + band->f_stepsize *= 0.5; + + band->i_stepsize = 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 |