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Code Issues Releases Activity

Simplify "deloco" and support decoding of 48bit loco png.

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This commit is contained in:
Carl Eugen Hoyos 2012-01-31 00:03:26 +01:00
parent f0d6828dbe
commit ea604de91e
1 changed files with 31 additions and 53 deletions
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84
libavcodec/pngdec.c
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@ -260,46 +260,21 @@ static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
}
}
static av_always_inline void convert_to_rgb32_loco(uint8_t *dst, const uint8_t *src, int width, int loco)
{
int j;
unsigned int r, g, b, a;
for(j = 0;j < width; j++) {
r = src[0];
g = src[1];
b = src[2];
a = src[3];
if(loco) {
r = (r+g)&0xff;
b = (b+g)&0xff;
}
dst[0] = r;
dst[1] = g;
dst[2] = b;
dst[3] = a;
dst += 4;
src += 4;
}
/* This used to be called "deloco" in FFmpeg
* and is actually an inverse reversible colorspace transformation */
#define YUV2RGB(NAME, TYPE) \
static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
{ \
int i; \
for (i = 0; i < size; i += 3 + alpha) { \
int g = dst [i+1]; \
dst[i+0] += g; \
dst[i+2] += g; \
} \
}
static void convert_to_rgb32(uint8_t *dst, const uint8_t *src, int width, int loco)
{
if(loco)
convert_to_rgb32_loco(dst, src, width, 1);
else
memcpy(dst, src, width * 4);
}
static void deloco_rgb24(uint8_t *dst, int size)
{
int i;
for(i=0; i<size; i+=3) {
int g = dst[i+1];
dst[i+0] += g;
dst[i+2] += g;
}
}
YUV2RGB(rgb8, uint8_t)
YUV2RGB(rgb16, uint16_t)
/* process exactly one decompressed row */
static void png_handle_row(PNGDecContext *s)
@ -309,14 +284,6 @@ static void png_handle_row(PNGDecContext *s)
if (!s->interlace_type) {
ptr = s->image_buf + s->image_linesize * s->y;
/* need to swap bytes correctly for RGB_ALPHA */
if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
png_filter_row(s, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
s->last_row, s->row_size, s->bpp);
convert_to_rgb32(ptr, s->tmp_row, s->width, s->filter_type == PNG_FILTER_TYPE_LOCO);
FFSWAP(uint8_t*, s->last_row, s->tmp_row);
} else {
/* in normal case, we avoid one copy */
if (s->y == 0)
last_row = s->last_row;
else
@ -324,17 +291,28 @@ static void png_handle_row(PNGDecContext *s)
png_filter_row(s, ptr, s->crow_buf[0], s->crow_buf + 1,
last_row, s->row_size, s->bpp);
}
/* loco lags by 1 row so that it doesn't interfere with top prediction */
if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
s->color_type == PNG_COLOR_TYPE_RGB && s->y > 0)
deloco_rgb24(ptr - s->image_linesize, s->row_size);
if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
if (s->bit_depth == 16) {
deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
} else {
deloco_rgb8(ptr - s->image_linesize, s->row_size,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
}
}
s->y++;
if (s->y == s->height) {
s->state |= PNG_ALLIMAGE;
if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
s->color_type == PNG_COLOR_TYPE_RGB)
deloco_rgb24(ptr, s->row_size);
if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
if (s->bit_depth == 16) {
deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
} else {
deloco_rgb8(ptr, s->row_size,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
}
}
}
} else {
got_line = 0;