ffmpeg | branch: master | Michael Niedermayer <[email protected]> | Wed Jun 24 17:05:42 2015 +0200| [05ef6324d11017420a087150f2addbb18cdb9ad3] | committer: Michael Niedermayer
avcodec/jpeg2000dec: Add 5/3 de-quantization special case for the lossless case This avoids a multiplication and 64bits Signed-off-by: Michael Niedermayer <[email protected]> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=05ef6324d11017420a087150f2addbb18cdb9ad3 --- libavcodec/jpeg2000dec.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c index be78660..11f4cd6 100644 --- a/libavcodec/jpeg2000dec.c +++ b/libavcodec/jpeg2000dec.c @@ -1436,8 +1436,14 @@ static void dequantization_int(int x, int y, Jpeg2000Cblk *cblk, for (j = 0; j < (cblk->coord[1][1] - cblk->coord[1][0]); ++j) { int32_t *datap = &comp->i_data[(comp->coord[0][1] - comp->coord[0][0]) * (y + j) + x]; int *src = t1->data[j]; - for (i = 0; i < w; ++i) - datap[i] = (src[i] * (int64_t)band->i_stepsize) / 32768; + if (band->i_stepsize == 16384) { + for (i = 0; i < w; ++i) + datap[i] = src[i] / 2; + } else { + // This should be VERY uncommon + for (i = 0; i < w; ++i) + datap[i] = (src[i] * (int64_t)band->i_stepsize) / 32768; + } } } _______________________________________________ ffmpeg-cvslog mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog
