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atrac3: simplify some loop indexing

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This commit is contained in:
Justin Ruggles 2012-10-18 17:07:04 -04:00
parent e55d53905f
commit aefdb735c3
1 changed files with 30 additions and 30 deletions
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60
libavcodec/atrac3.c
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@ -551,7 +551,7 @@ static void reverse_matrixing(float *su1, float *su2, int *prev_code,
for (i = 0, band = 0; band < 4 * 256; band += 256, i++) {
int s1 = prev_code[i];
int s2 = curr_code[i];
nsample = 0;
nsample = band;
if (s1 != s2) {
/* Selector value changed, interpolation needed. */
@ -561,41 +561,41 @@ static void reverse_matrixing(float *su1, float *su2, int *prev_code,
mc2_r = matrix_coeffs[s2 * 2 + 1];
/* Interpolation is done over the first eight samples. */
for (; nsample < 8; nsample++) {
float c1 = su1[band + nsample];
float c2 = su2[band + nsample];
c2 = c1 * INTERPOLATE(mc1_l, mc2_l, nsample) +
c2 * INTERPOLATE(mc1_r, mc2_r, nsample);
su1[band + nsample] = c2;
su2[band + nsample] = c1 * 2.0 - c2;
for (; nsample < band + 8; nsample++) {
float c1 = su1[nsample];
float c2 = su2[nsample];
c2 = c1 * INTERPOLATE(mc1_l, mc2_l, nsample - band) +
c2 * INTERPOLATE(mc1_r, mc2_r, nsample - band);
su1[nsample] = c2;
su2[nsample] = c1 * 2.0 - c2;
}
}
/* Apply the matrix without interpolation. */
switch (s2) {
case 0: /* M/S decoding */
for (; nsample < 256; nsample++) {
float c1 = su1[band + nsample];
float c2 = su2[band + nsample];
su1[band + nsample] = c2 * 2.0;
su2[band + nsample] = (c1 - c2) * 2.0;
for (; nsample < band + 256; nsample++) {
float c1 = su1[nsample];
float c2 = su2[nsample];
su1[nsample] = c2 * 2.0;
su2[nsample] = (c1 - c2) * 2.0;
}
break;
case 1:
for (; nsample < 256; nsample++) {
float c1 = su1[band + nsample];
float c2 = su2[band + nsample];
su1[band + nsample] = (c1 + c2) * 2.0;
su2[band + nsample] = c2 * -2.0;
for (; nsample < band + 256; nsample++) {
float c1 = su1[nsample];
float c2 = su2[nsample];
su1[nsample] = (c1 + c2) * 2.0;
su2[nsample] = c2 * -2.0;
}
break;
case 2:
case 3:
for (; nsample < 256; nsample++) {
float c1 = su1[band + nsample];
float c2 = su2[band + nsample];
su1[band + nsample] = c1 + c2;
su2[band + nsample] = c1 - c2;
for (; nsample < band + 256; nsample++) {
float c1 = su1[nsample];
float c2 = su2[nsample];
su1[nsample] = c1 + c2;
su2[nsample] = c1 - c2;
}
break;
default:
@ -627,14 +627,14 @@ static void channel_weighting(float *su1, float *su2, int *p3)
get_channel_weights(p3[1], p3[0], w[0]);
get_channel_weights(p3[3], p3[2], w[1]);
for (band = 1; band < 4; band++) {
for (nsample = 0; nsample < 8; nsample++) {
su1[band * 256 + nsample] *= INTERPOLATE(w[0][0], w[0][1], nsample);
su2[band * 256 + nsample] *= INTERPOLATE(w[1][0], w[1][1], nsample);
for (band = 256; band < 4 * 256; band += 256) {
for (nsample = band; nsample < band + 8; nsample++) {
su1[nsample] *= INTERPOLATE(w[0][0], w[0][1], nsample - band);
su2[nsample] *= INTERPOLATE(w[1][0], w[1][1], nsample - band);
}
for(; nsample < 256; nsample++) {
su1[band * 256 + nsample] *= w[1][0];
su2[band * 256 + nsample] *= w[1][1];
for(; nsample < band + 256; nsample++) {
su1[nsample] *= w[1][0];
su2[nsample] *= w[1][1];
}
}
}