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Move DitherCombine8x8 to dsp/dec.c

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To be later optimized in SSE2

Change-Id: I0de9c89eb5166f3319bb4b0500150de271ecac05
This commit is contained in:
Pascal Massimino 2016-05-24 23:14:41 -07:00
parent 2ec2de1450
commit 77f21c9c39
3 changed files with 40 additions and 19 deletions
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28
src/dec/frame.c
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@ -316,6 +316,9 @@ static void PrecomputeFilterStrengths(VP8Decoder* const dec) {
//------------------------------------------------------------------------------
// Dithering
// minimal amp that will provide a non-zero dithering effect
#define MIN_DITHER_AMP 4
#define DITHER_AMP_TAB_SIZE 12
static const int kQuantToDitherAmp[DITHER_AMP_TAB_SIZE] = {
// roughly, it's dqm->uv_mat_[1]
@ -356,27 +359,14 @@ void VP8InitDithering(const WebPDecoderOptions* const options,
}
}
// minimal amp that will provide a non-zero dithering effect
#define MIN_DITHER_AMP 4
#define DITHER_DESCALE 4
#define DITHER_DESCALE_ROUNDER (1 << (DITHER_DESCALE - 1))
#define DITHER_AMP_BITS 8
#define DITHER_AMP_CENTER (1 << DITHER_AMP_BITS)
// Convert to range: [-2,2] for dither=50, [-4,4] for dither=100
static void Dither8x8(VP8Random* const rg, uint8_t* dst, int bps, int amp) {
int i, j;
for (j = 0; j < 8; ++j) {
for (i = 0; i < 8; ++i) {
// TODO: could be made faster with SSE2
const int bits =
VP8RandomBits2(rg, DITHER_AMP_BITS + 1, amp) - DITHER_AMP_CENTER;
// Convert to range: [-2,2] for dither=50, [-4,4] for dither=100
const int delta = (bits + DITHER_DESCALE_ROUNDER) >> DITHER_DESCALE;
const int v = (int)dst[i] + delta;
dst[i] = (v < 0) ? 0 : (v > 255) ? 255u : (uint8_t)v;
}
dst += bps;
uint8_t dither[64];
int i;
for (i = 0; i < 8 * 8; ++i) {
dither[i] = VP8RandomBits2(rg, VP8_DITHER_AMP_BITS + 1, amp);
}
VP8DitherCombine8x8(dither, dst, bps);
}
static void DitherRow(VP8Decoder* const dec) {

22
src/dsp/dec.c
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@ -655,6 +655,23 @@ static void HFilter8i(uint8_t* u, uint8_t* v, int stride,
//------------------------------------------------------------------------------
static void DitherCombine8x8(const uint8_t* dither, uint8_t* dst,
int dst_stride) {
int i, j;
for (j = 0; j < 8; ++j) {
for (i = 0; i < 8; ++i) {
const int delta0 = dither[i] - VP8_DITHER_AMP_CENTER;
const int delta1 =
(delta0 + VP8_DITHER_DESCALE_ROUNDER) >> VP8_DITHER_DESCALE;
dst[i] = clip_8b((int)dst[i] + delta1);
}
dst += dst_stride;
dither += 8;
}
}
//------------------------------------------------------------------------------
VP8DecIdct2 VP8Transform;
VP8DecIdct VP8TransformAC3;
VP8DecIdct VP8TransformUV;
@ -674,6 +691,9 @@ VP8SimpleFilterFunc VP8SimpleHFilter16;
VP8SimpleFilterFunc VP8SimpleVFilter16i;
VP8SimpleFilterFunc VP8SimpleHFilter16i;
void (*VP8DitherCombine8x8)(const uint8_t* dither, uint8_t* dst,
int dst_stride);
extern void VP8DspInitSSE2(void);
extern void VP8DspInitSSE41(void);
extern void VP8DspInitNEON(void);
@ -735,6 +755,8 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8DspInit(void) {
VP8PredChroma8[5] = DC8uvNoLeft;
VP8PredChroma8[6] = DC8uvNoTopLeft;
VP8DitherCombine8x8 = DitherCombine8x8;
// If defined, use CPUInfo() to overwrite some pointers with faster versions.
if (VP8GetCPUInfo != NULL) {
#if defined(WEBP_USE_SSE2)

9
src/dsp/dsp.h
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@ -321,6 +321,15 @@ extern VP8LumaFilterFunc VP8HFilter16i;
extern VP8ChromaFilterFunc VP8VFilter8i; // filtering u and v altogether
extern VP8ChromaFilterFunc VP8HFilter8i;
// Dithering. Combines dithering values (centered around 128) with dst[],
// according to: dst[] = clip(dst[] + (((dither[]-128) + 8) >> 4)
#define VP8_DITHER_DESCALE 4
#define VP8_DITHER_DESCALE_ROUNDER (1 << (VP8_DITHER_DESCALE - 1))
#define VP8_DITHER_AMP_BITS 7
#define VP8_DITHER_AMP_CENTER (1 << VP8_DITHER_AMP_BITS)
extern void (*VP8DitherCombine8x8)(const uint8_t* dither, uint8_t* dst,
int dst_stride);
// must be called before anything using the above
void VP8DspInit(void);