ffmpeg/FFmpeg
1
0
Fork 0
mirror of https://git.ffmpeg.org/ffmpeg.git synced 2024-09-20 05:16:38 +00:00
Code Issues Packages Projects Releases Wiki Activity

AC-3 decoder, soc revision 72, Sep 7 04:20:00 2006 UTC by cloud9

Browse Source 
fix short block imdct.

Originally committed as revision 9670 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2007-07-14 16:04:40 +00:00
parent c7cfc48f37
commit 1ea76064b4
1 changed files with 19 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
libavcodec/ac3dec.c
View File

@ -1609,7 +1609,8 @@ static void do_imdct_256(AC3DecodeContext *ctx, int chindex)
{
int k;
float x1[128], x2[128];
float *ptr;
float *o_ptr, *d_ptr, *w;
FFTComplex *ptr1, *ptr2;
for (k = 0; k < N / 4; k++) {
x1[k] = ctx->transform_coeffs[chindex][2 * k];
@ -1619,10 +1620,23 @@ static void do_imdct_256(AC3DecodeContext *ctx, int chindex)
ff_imdct_calc(&ctx->imdct_256, ctx->tmp_output, x1, ctx->tmp_imdct);
ff_imdct_calc(&ctx->imdct_256, ctx->tmp_output + 256, x2, 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);
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];
}
}
/* This function performs the imdct on 512 sample transform