dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-07-15 21:39:59 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

Special-case sparse transform

Browse Source 
If the number of non-zero coeffs is <= 3, use a
simplified transform for luma.

Change-Id: I78a1252704228d21720d4bc1221252c84338d9c8
This commit is contained in:
skal
2013-10-08 22:05:38 +02:00
parent 00125196f3
commit f9bbc2a034
6 changed files with 159 additions and 72 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
src/dsp/dec.c
View File

@ -61,6 +61,14 @@ static WEBP_INLINE uint8_t clip_8b(int v) {
#define STORE(x, y, v) \
dst[x + y * BPS] = clip_8b(dst[x + y * BPS] + ((v) >> 3))
#define STORE2(y, dc, d, c) do { \
const int DC = (dc); \
STORE(0, y, DC + (d)); \
STORE(1, y, DC + (c)); \
STORE(2, y, DC - (c)); \
STORE(3, y, DC - (d)); \
} while (0)
static const int kC1 = 20091 + (1 << 16);
static const int kC2 = 35468;
#define MUL(a, b) (((a) * (b)) >> 16)
@ -103,7 +111,21 @@ static void TransformOne(const int16_t* in, uint8_t* dst) {
dst += BPS;
}
}
// Simplified transform when only in[0], in[1] and in[4] are non-zero
static void TransformAC3(const int16_t* in, uint8_t* dst) {
const int a = in[0] + 4;
const int c4 = MUL(in[4], kC2);
const int d4 = MUL(in[4], kC1);
const int c1 = MUL(in[1], kC2);
const int d1 = MUL(in[1], kC1);
STORE2(0, a + d4, d1, c1);
STORE2(1, a + c4, d1, c1);
STORE2(2, a - c4, d1, c1);
STORE2(3, a - d4, d1, c1);
}
#undef MUL
#undef STORE2
static void TransformTwo(const int16_t* in, uint8_t* dst, int do_two) {
TransformOne(in, dst);
@ -679,6 +701,7 @@ static void HFilter8i(uint8_t* u, uint8_t* v, int stride,
//------------------------------------------------------------------------------
VP8DecIdct2 VP8Transform;
VP8DecIdct VP8TransformAC3;
VP8DecIdct VP8TransformUV;
VP8DecIdct VP8TransformDC;
VP8DecIdct VP8TransformDCUV;
@ -706,6 +729,7 @@ void VP8DspInit(void) {
VP8TransformUV = TransformUV;
VP8TransformDC = TransformDC;
VP8TransformDCUV = TransformDCUV;
VP8TransformAC3 = TransformAC3;
VP8VFilter16 = VFilter16;
VP8HFilter16 = HFilter16;