diff options
author | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2013-12-21 08:13:29 +0400 |
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committer | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2013-12-21 08:13:29 +0400 |
commit | 2e26b82ec24060f61bc553d1f36efad49d97167e (patch) | |
tree | f117eec6d7bff76293d5c1c617dd2f260c1b1699 /celt/mdct.c | |
parent | 8e02afcfff4d1e4ddbf06a5b6878d49d6c3fccb5 (diff) |
Moves the bitrev step to the IMDCT pre-rotation
Diffstat (limited to 'celt/mdct.c')
-rw-r--r-- | celt/mdct.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/celt/mdct.c b/celt/mdct.c index 90a214ad..b4209195 100644 --- a/celt/mdct.c +++ b/celt/mdct.c @@ -214,13 +214,13 @@ void clt_mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scala int i; int N, N2, N4; kiss_twiddle_scalar sine; - VARDECL(kiss_fft_scalar, f2); + VARDECL(kiss_fft_cpx, f2); SAVE_STACK; N = l->n; N >>= shift; N2 = N>>1; N4 = N>>2; - ALLOC(f2, N2, kiss_fft_scalar); + ALLOC(f2, N4, kiss_fft_cpx); /* sin(x) ~= x here */ #ifdef FIXED_POINT sine = TRIG_UPSCALE*(QCONST16(0.7853981f, 15)+N2)/N; @@ -233,23 +233,26 @@ void clt_mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scala /* Temp pointers to make it really clear to the compiler what we're doing */ const kiss_fft_scalar * OPUS_RESTRICT xp1 = in; const kiss_fft_scalar * OPUS_RESTRICT xp2 = in+stride*(N2-1); - kiss_fft_scalar * OPUS_RESTRICT yp = f2; - const kiss_twiddle_scalar *t = &l->trig[0]; + kiss_fft_cpx * OPUS_RESTRICT yp = f2; + const kiss_twiddle_scalar * OPUS_RESTRICT t = &l->trig[0]; + const opus_int16 * OPUS_RESTRICT bitrev = l->kfft[shift]->bitrev; for(i=0;i<N4;i++) { kiss_fft_scalar yr, yi; + kiss_fft_cpx yc; yr = -S_MUL(*xp2, t[i<<shift]) + S_MUL(*xp1,t[(N4-i)<<shift]); yi = -S_MUL(*xp2, t[(N4-i)<<shift]) - S_MUL(*xp1,t[i<<shift]); /* works because the cos is nearly one */ - *yp++ = yr - S_MUL(yi,sine); - *yp++ = yi + S_MUL(yr,sine); + yc.r = yr - S_MUL(yi,sine); + yc.i = yi + S_MUL(yr,sine); + /* Storing the pre-rotation directly in the bitrev order. */ + yp[*bitrev++] = yc; xp1+=2*stride; xp2-=2*stride; } } - /* Inverse N/4 complex FFT. This one should *not* downscale even in fixed-point */ - opus_ifft(l->kfft[shift], (kiss_fft_cpx *)f2, (kiss_fft_cpx *)(out+(overlap>>1))); + opus_ifft_impl(l->kfft[shift], f2); /* Post-rotate and de-shuffle from both ends of the buffer at once to make it in-place. */ @@ -263,15 +266,15 @@ void clt_mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scala { kiss_fft_scalar re, im, yr, yi; kiss_twiddle_scalar t0, t1; - re = yp0[0]; - im = yp0[1]; + re = f2[i].r; + im = f2[i].i; t0 = t[i<<shift]; t1 = t[(N4-i)<<shift]; /* We'd scale up by 2 here, but instead it's done when mixing the windows */ yr = S_MUL(re,t0) - S_MUL(im,t1); yi = S_MUL(im,t0) + S_MUL(re,t1); - re = yp1[0]; - im = yp1[1]; + re = f2[N4-i-1].r; + im = f2[N4-i-1].i; /* works because the cos is nearly one */ yp0[0] = -(yr - S_MUL(yi,sine)); yp1[1] = yi + S_MUL(yr,sine); |