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simplify the fwd transform

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-> remove two shifts

Change-Id: Ibc55bca98588da30553a7870224ffd0e13d57f52
This commit is contained in:
skal
2012-11-15 09:51:35 +01:00
parent b542611964
commit 42c3b550ba
3 changed files with 60 additions and 60 deletions
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22
src/dsp/enc.c
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@@ -134,25 +134,25 @@ static void FTransform(const uint8_t* src, const uint8_t* ref, int16_t* out) {
int i;
int tmp[16];
for (i = 0; i < 4; ++i, src += BPS, ref += BPS) {
const int d0 = src[0] - ref[0];
const int d0 = src[0] - ref[0]; // 9bit dynamic range ([-255,255])
const int d1 = src[1] - ref[1];
const int d2 = src[2] - ref[2];
const int d3 = src[3] - ref[3];
const int a0 = (d0 + d3) << 3;
const int a1 = (d1 + d2) << 3;
const int a2 = (d1 - d2) << 3;
const int a3 = (d0 - d3) << 3;
tmp[0 + i * 4] = (a0 + a1);
tmp[1 + i * 4] = (a2 * 2217 + a3 * 5352 + 14500) >> 12;
tmp[2 + i * 4] = (a0 - a1);
tmp[3 + i * 4] = (a3 * 2217 - a2 * 5352 + 7500) >> 12;
const int a0 = (d0 + d3); // 10b [-510,510]
const int a1 = (d1 + d2);
const int a2 = (d1 - d2);
const int a3 = (d0 - d3);
tmp[0 + i * 4] = (a0 + a1) << 3; // 14b [-8160,8160]
tmp[1 + i * 4] = (a2 * 2217 + a3 * 5352 + 1812) >> 9; // [-7536,7542]
tmp[2 + i * 4] = (a0 - a1) << 3;
tmp[3 + i * 4] = (a3 * 2217 - a2 * 5352 + 937) >> 9;
}
for (i = 0; i < 4; ++i) {
const int a0 = (tmp[0 + i] + tmp[12 + i]);
const int a0 = (tmp[0 + i] + tmp[12 + i]); // 15b
const int a1 = (tmp[4 + i] + tmp[ 8 + i]);
const int a2 = (tmp[4 + i] - tmp[ 8 + i]);
const int a3 = (tmp[0 + i] - tmp[12 + i]);
out[0 + i] = (a0 + a1 + 7) >> 4;
out[0 + i] = (a0 + a1 + 7) >> 4; // 12b
out[4 + i] = ((a2 * 2217 + a3 * 5352 + 12000) >> 16) + (a3 != 0);
out[8 + i] = (a0 - a1 + 7) >> 4;
out[12+ i] = ((a3 * 2217 - a2 * 5352 + 51000) >> 16);