c - 处理交错样本

Question

有一个接受样本的代码。它们最初是单声道的，我在生成时将它们交错为立体声。现在它们使用以下功能进行过滤，但我现在不知道如何正确地通过左右通道进行迭代，因为它是为单声道样本设计的。

int32 *in是现在立体声的缓冲区。int32 *out是最终输出的过滤缓冲区。

#define SQ2NCOEFFS 1024
mrindex = (SQ2NCOEFFS + 1) << 16;
mrratio = (PAL ? (int64)(PAL_CPU * 65536) : (int64)(NTSC_CPU * 65536)) / rate;
int32 count = 0;
for (x = mrindex; x < max; x += mrratio) {
    int32 acc = 0, acc2 = 0;
    unsigned int c;
    int32 *S, *D;
    for (c = SQ2NCOEFFS, S = &in[(x >> 16) - SQ2NCOEFFS], D = sq2coeffs; c; c--, D++) {
        acc += (S[c] * *D) >> 6;
        acc2 += (S[1+c] * *D) >> 6;
    }
    acc = ((int64)acc * (65536 - (x & 65535)) + (int64)acc2 * (x & 65535)) >> (16 + 11);
    *out = acc;
    out++;
    count++;
}