From 3a9852be1c2fa1fc6da47fedef978476c82ec951 Mon Sep 17 00:00:00 2001 From: Dave Hooper Date: Thu, 18 Feb 2010 00:14:13 +0000 Subject: [PATCH] I don't yet fully understand why this is required, but without it the output is signed-inverted (compared to e.g. the output of oggdec). ac3 confirmed to be ok so the problem must be in the imdct not the ifft. but the algo seems correct (in that seems same as original ffmpeg version).. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24739 a1c6a512-1295-4272-9138-f99709370657 --- apps/codecs/lib/mdct.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/apps/codecs/lib/mdct.c b/apps/codecs/lib/mdct.c index 03baa4db4a..3c9fe41f20 100644 --- a/apps/codecs/lib/mdct.c +++ b/apps/codecs/lib/mdct.c @@ -139,10 +139,10 @@ void ff_imdct_half(unsigned int nbits, fixed32 *output, const fixed32 *input) fixed32 r0,i0,r1,i1; XNPROD31_R(z1[1], z1[0], T[0], T[1], r0, i1 ); T+=newstep; XNPROD31_R(z2[1], z2[0], T[1], T[0], r1, i0 ); T+=newstep; - z1[0] = r0; - z1[1] = i0; - z2[0] = r1; - z2[1] = i1; + z1[0] = -r0; + z1[1] = -i0; + z2[0] = -r1; + z2[1] = -i1; z1+=2; z2-=2; } @@ -171,10 +171,10 @@ void ff_imdct_half(unsigned int nbits, fixed32 *output, const fixed32 *input) v0 += (t0 = (T[0]>>1)); v1 += (t1 = (T[1]>>1)); XNPROD31_R(z2[1], z2[0], v1, v0, r1, i0 ); - z1[0] = r0; - z1[1] = i0; - z2[0] = r1; - z2[1] = i1; + z1[0] = -r0; + z1[1] = -i0; + z2[0] = -r1; + z2[1] = -i1; z1+=2; z2-=2; V+=2; @@ -205,10 +205,10 @@ void ff_imdct_half(unsigned int nbits, fixed32 *output, const fixed32 *input) t0 = v0-q0; t1 = v1-q1; XNPROD31_R(z2[1], z2[0], t1, t0, r1, i0 ); - z1[0] = r0; - z1[1] = i0; - z2[0] = r1; - z2[1] = i1; + z1[0] = -r0; + z1[1] = -i0; + z2[0] = -r1; + z2[1] = -i1; z1+=2; z2-=2; T+=2; @@ -220,10 +220,10 @@ void ff_imdct_half(unsigned int nbits, fixed32 *output, const fixed32 *input) v0 = t0-q0; v1 = t1-q1; XNPROD31_R(z2[1], z2[0], v1, v0, r1, i0 ); - z1[0] = r0; - z1[1] = i0; - z2[0] = r1; - z2[1] = i1; + z1[0] = -r0; + z1[1] = -i0; + z2[0] = -r1; + z2[1] = -i1; z1+=2; z2-=2; V+=2;