diff options
| -rw-r--r-- | libavcodec/ac3dec.c | 95 |
1 files changed, 45 insertions, 50 deletions
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c index 5028385568..eaf669285a 100644 --- a/libavcodec/ac3dec.c +++ b/libavcodec/ac3dec.c @@ -85,8 +85,6 @@ static const float clevs[4] = { LEVEL_MINUS_3DB, LEVEL_MINUS_4POINT5DB, static const float slevs[4] = { LEVEL_MINUS_3DB, LEVEL_MINUS_6DB, LEVEL_ZERO, LEVEL_MINUS_6DB }; -#define N 512 /* constant for IMDCT Block size */ - #define BLOCK_SIZE 256 /* Output and input configurations. */ @@ -1379,66 +1377,63 @@ static void do_downmix(AC3DecodeContext *ctx) */ static void do_imdct_256(AC3DecodeContext *ctx, int chindex) { - int k; - float x1[128], x2[128]; - float *o_ptr, *d_ptr, *w; - FFTComplex *ptr1, *ptr2; - - for (k = 0; k < N / 4; k++) { - x1[k] = ctx->transform_coeffs[chindex][2 * k]; - x2[k] = ctx->transform_coeffs[chindex][2 * k + 1]; - } + int i, k; + float x[128]; + FFTComplex z[2][64]; + float *o_ptr = ctx->tmp_output; + + for(i=0; i<2; i++) { + /* de-interleave coefficients */ + for(k=0; k<128; k++) { + x[k] = ctx->transform_coeffs[chindex][2*k+i]; + } - ctx->imdct_256.fft.imdct_calc(&ctx->imdct_256, ctx->tmp_output, x1, ctx->tmp_imdct); - ctx->imdct_256.fft.imdct_calc(&ctx->imdct_256, ctx->tmp_output + 256, x2, ctx->tmp_imdct); - - o_ptr = ctx->output[chindex]; - d_ptr = ctx->delay[chindex]; - ptr1 = (FFTComplex *)ctx->tmp_output; - ptr2 = (FFTComplex *)ctx->tmp_output + 256; - w = ctx->window; - - for (k = 0; k < N / 8; k++) - { - o_ptr[2 * k] = -ptr1[k].im * w[2 * k] + d_ptr[2 * k] + 384.0; - o_ptr[2 * k + 1] = ptr1[N / 8 - k - 1].re * w[2 * k + 1] + 384.0; - o_ptr[N / 4 + 2 * k] = -ptr1[k].re * w[N / 4 + 2 * k] + d_ptr[N / 4 + 2 * k] + 384.0; - o_ptr[N / 4 + 2 * k + 1] = ptr1[N / 8 - k - 1].im * w[N / 4 + 2 * k + 1] + d_ptr[N / 4 + 2 * k + 1] + 384.0; - d_ptr[2 * k] = ptr2[k].re * w[k / 2 - 2 * k - 1]; - d_ptr[2 * k + 1] = -ptr2[N / 8 - k - 1].im * w[N / 2 - 2 * k - 2]; - d_ptr[N / 4 + 2 * k] = ptr2[k].im * w[N / 4 - 2 * k - 1]; - d_ptr[N / 4 + 2 * k + 1] = -ptr2[N / 8 - k - 1].re * w[N / 4 - 2 * k - 2]; + /* run standard IMDCT */ + ctx->imdct_256.fft.imdct_calc(&ctx->imdct_256, o_ptr, x, ctx->tmp_imdct); + + /* reverse the post-rotation & reordering from standard IMDCT */ + for(k=0; k<32; k++) { + z[i][32+k].re = -o_ptr[128+2*k]; + z[i][32+k].im = -o_ptr[2*k]; + z[i][31-k].re = o_ptr[2*k+1]; + z[i][31-k].im = o_ptr[128+2*k+1]; + } } -} -/* This function performs the imdct on 512 sample transform - * coefficients. - */ -static void do_imdct_512(AC3DecodeContext *ctx, int chindex) -{ - float *ptr; - - ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output, - ctx->transform_coeffs[chindex], ctx->tmp_imdct); - ptr = ctx->output[chindex]; - ctx->dsp.vector_fmul_add_add(ptr, ctx->tmp_output, ctx->window, ctx->delay[chindex], 384, BLOCK_SIZE, 1); - ptr = ctx->delay[chindex]; - ctx->dsp.vector_fmul_reverse(ptr, ctx->tmp_output + 256, ctx->window, BLOCK_SIZE); + /* apply AC-3 post-rotation & reordering */ + for(k=0; k<64; k++) { + o_ptr[ 2*k ] = -z[0][ k].im; + o_ptr[ 2*k+1] = z[0][63-k].re; + o_ptr[128+2*k ] = -z[0][ k].re; + o_ptr[128+2*k+1] = z[0][63-k].im; + o_ptr[256+2*k ] = -z[1][ k].re; + o_ptr[256+2*k+1] = z[1][63-k].im; + o_ptr[384+2*k ] = z[1][ k].im; + o_ptr[384+2*k+1] = -z[1][63-k].re; + } } /* IMDCT Transform. */ static inline void do_imdct(AC3DecodeContext *ctx) { - int i; + int ch; if (ctx->blkoutput & AC3_OUTPUT_LFEON) { - do_imdct_512(ctx, 0); + ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output, + ctx->transform_coeffs[0], ctx->tmp_imdct); } - for (i = 0; i < ctx->nfchans; i++) { - if ((ctx->blksw >> i) & 1) - do_imdct_256(ctx, i + 1); + for (ch=1; ch<=ctx->nfchans; ch++) { + if ((ctx->blksw >> (ch-1)) & 1) + do_imdct_256(ctx, ch); else - do_imdct_512(ctx, i + 1); + ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output, + ctx->transform_coeffs[ch], + ctx->tmp_imdct); + + ctx->dsp.vector_fmul_add_add(ctx->output[ch], ctx->tmp_output, + ctx->window, ctx->delay[ch], 384, 256, 1); + ctx->dsp.vector_fmul_reverse(ctx->delay[ch], ctx->tmp_output+256, + ctx->window, 256); } } |