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avcodec/mjpegdec: Simplify masking in ljpeg_decode_yuv_scan() 

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2013-09-05 01:32:51 +02:00
parent b394ccfe47
commit b042712a87
1 changed files with 6 additions and 5 deletions
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11
libavcodec/mjpegdec.c
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@ -886,12 +886,13 @@ static int ljpeg_decode_rgb_scan(MJpegDecodeContext *s, int nb_components, int p
static int ljpeg_decode_yuv_scan(MJpegDecodeContext *s, int predictor,
int point_transform, int nb_components)
{
int i, mb_x, mb_y;
int i, mb_x, mb_y, mask;
int bits= (s->bits+7)&~7;
int resync_mb_y = 0;
int resync_mb_x = 0;
point_transform += bits - s->bits;
mask = ((1 << s->bits) - 1) << point_transform;
av_assert0(nb_components>=1 && nb_components<=4);
@ -944,7 +945,7 @@ static int ljpeg_decode_yuv_scan(MJpegDecodeContext *s, int predictor,
if (s->interlaced && s->bottom_field)
ptr += linesize >> 1;
pred &= (-1)<<(8 - s->bits + point_transform);
pred &= mask;
*ptr= pred + (dc << point_transform);
}else{
ptr16 = (uint16_t*)(s->picture.data[c] + 2*(linesize * (v * mb_y + y)) + 2*(h * mb_x + x)); //FIXME optimize this crap
@ -964,7 +965,7 @@ static int ljpeg_decode_yuv_scan(MJpegDecodeContext *s, int predictor,
if (s->interlaced && s->bottom_field)
ptr16 += linesize >> 1;
pred &= (-1)<<(16 - s->bits + point_transform);
pred &= mask;
*ptr16= pred + (dc << point_transform);
}
if (++x == h) {
@ -1000,13 +1001,13 @@ static int ljpeg_decode_yuv_scan(MJpegDecodeContext *s, int predictor,
(h * mb_x + x); //FIXME optimize this crap
PREDICT(pred, ptr[-linesize-1], ptr[-linesize], ptr[-1], predictor);
pred &= (-1)<<(8 - s->bits + point_transform);
pred &= mask;
*ptr = pred + (dc << point_transform);
}else{
ptr16 = (uint16_t*)(s->picture.data[c] + 2*(linesize * (v * mb_y + y)) + 2*(h * mb_x + x)); //FIXME optimize this crap
PREDICT(pred, ptr16[-linesize-1], ptr16[-linesize], ptr16[-1], predictor);
pred &= (-1)<<(16 - s->bits + point_transform);
pred &= mask;
*ptr16= pred + (dc << point_transform);
}