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Expand the idct4_c() function in idct8_c()

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Change-Id: I5afa3c351ba7c5e7deb3889f7471619ac60af255
This commit is contained in:
Angie Chiang 2015-08-26 17:40:52 -07:00
parent 6201a256f4
commit 45db71d0ac
1 changed files with 14 additions and 5 deletions
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19
vpx_dsp/inv_txfm.c
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@ -170,16 +170,25 @@ void idct8_c(const tran_low_t *input, tran_low_t *output) {
step1[5] = WRAPLOW(dct_const_round_shift(temp1), 8);
step1[6] = WRAPLOW(dct_const_round_shift(temp2), 8);
// stage 2 & stage 3 - even half
idct4_c(step1, step1);
// stage 2 - odd half
// stage 2
temp1 = (step1[0] + step1[2]) * cospi_16_64;
temp2 = (step1[0] - step1[2]) * cospi_16_64;
step2[0] = WRAPLOW(dct_const_round_shift(temp1), 8);
step2[1] = WRAPLOW(dct_const_round_shift(temp2), 8);
temp1 = step1[1] * cospi_24_64 - step1[3] * cospi_8_64;
temp2 = step1[1] * cospi_8_64 + step1[3] * cospi_24_64;
step2[2] = WRAPLOW(dct_const_round_shift(temp1), 8);
step2[3] = WRAPLOW(dct_const_round_shift(temp2), 8);
step2[4] = WRAPLOW(step1[4] + step1[5], 8);
step2[5] = WRAPLOW(step1[4] - step1[5], 8);
step2[6] = WRAPLOW(-step1[6] + step1[7], 8);
step2[7] = WRAPLOW(step1[6] + step1[7], 8);
// stage 3 -odd half
// stage 3
step1[0] = WRAPLOW(step2[0] + step2[3], 8);
step1[1] = WRAPLOW(step2[1] + step2[2], 8);
step1[2] = WRAPLOW(step2[1] - step2[2], 8);
step1[3] = WRAPLOW(step2[0] - step2[3], 8);
step1[4] = step2[4];
temp1 = (step2[6] - step2[5]) * cospi_16_64;
temp2 = (step2[5] + step2[6]) * cospi_16_64;