diff options
author | Andree Buschmann <AndreeBuschmann@t-online.de> | 2012-10-16 18:06:16 +0200 |
---|---|---|
committer | Nils Wallménius <nils@rockbox.org> | 2012-10-16 18:07:52 +0200 |
commit | 091619b4a5cd3458e5f1a8f81d78f4234c461fcb (patch) | |
tree | 5e0b53b3821d5d06a46abc8d35864e3b555311ac /lib/rbcodec | |
parent | c8e7dae362517489dc803a2ac3279aacefe0c3bc (diff) |
opus: use two pointers for mdct pre and post rotation
avoids complicated index calculations in the loops.
saves 0.3MHz decoding a 64kbps test file on h300 (cf) and
0.2MHz on c200 (pp)
Change-Id: I1918912d9a4502f89980c6bb270ec2ef10a07010
Signed-off-by: Nils Wallménius <nils@rockbox.org>
Diffstat (limited to 'lib/rbcodec')
-rw-r--r-- | lib/rbcodec/codecs/libopus/celt/mdct.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/lib/rbcodec/codecs/libopus/celt/mdct.c b/lib/rbcodec/codecs/libopus/celt/mdct.c index 0f9af9eac4..877366361d 100644 --- a/lib/rbcodec/codecs/libopus/celt/mdct.c +++ b/lib/rbcodec/codecs/libopus/celt/mdct.c @@ -249,17 +249,20 @@ void clt_mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scala 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]; + const kiss_twiddle_scalar *t0 = &l->trig[0]; + const kiss_twiddle_scalar *t1 = &l->trig[N4<<shift]; for(i=0;i<N4;i++) { kiss_fft_scalar yr, yi; - 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]); + yr = -S_MUL(*xp2, *t0) + S_MUL(*xp1, *t1); + yi = -S_MUL(*xp2, *t1) - S_MUL(*xp1, *t0); /* works because the cos is nearly one */ *yp++ = yr - S_MUL(yi,sine); *yp++ = yi + S_MUL(yr,sine); xp1+=2*stride; xp2-=2*stride; + t0 += stride; + t1 -= stride; } } @@ -269,19 +272,21 @@ void clt_mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scala /* Post-rotate */ { kiss_fft_scalar * OPUS_RESTRICT fp = f; - const kiss_twiddle_scalar *t = &l->trig[0]; - + const kiss_twiddle_scalar *t0 = &l->trig[0]; + const kiss_twiddle_scalar *t1 = &l->trig[N4<<shift]; for(i=0;i<N4;i++) { kiss_fft_scalar re, im, yr, yi; re = fp[0]; im = fp[1]; /* We'd scale up by 2 here, but instead it's done when mixing the windows */ - yr = S_MUL(re,t[i<<shift]) - S_MUL(im,t[(N4-i)<<shift]); - yi = S_MUL(im,t[i<<shift]) + S_MUL(re,t[(N4-i)<<shift]); + yr = S_MUL(re, *t0) - S_MUL(im, *t1); + yi = S_MUL(im, *t0) + S_MUL(re, *t1); /* works because the cos is nearly one */ *fp++ = yr - S_MUL(yi,sine); *fp++ = yi + S_MUL(yr,sine); + t0 += stride; + t1 -= stride; } } /* De-shuffle the components for the middle of the window only */ |