1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/celt/mdct.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,70 @@
1.4 +/* Copyright (c) 2007-2008 CSIRO
1.5 + Copyright (c) 2007-2008 Xiph.Org Foundation
1.6 + Written by Jean-Marc Valin */
1.7 +/*
1.8 + Redistribution and use in source and binary forms, with or without
1.9 + modification, are permitted provided that the following conditions
1.10 + are met:
1.11 +
1.12 + - Redistributions of source code must retain the above copyright
1.13 + notice, this list of conditions and the following disclaimer.
1.14 +
1.15 + - Redistributions in binary form must reproduce the above copyright
1.16 + notice, this list of conditions and the following disclaimer in the
1.17 + documentation and/or other materials provided with the distribution.
1.18 +
1.19 + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1.20 + ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1.21 + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
1.22 + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
1.23 + OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
1.24 + EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
1.25 + PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
1.26 + PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
1.27 + LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
1.28 + NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
1.29 + SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.30 +*/
1.31 +
1.32 +/* This is a simple MDCT implementation that uses a N/4 complex FFT
1.33 + to do most of the work. It should be relatively straightforward to
1.34 + plug in pretty much and FFT here.
1.35 +
1.36 + This replaces the Vorbis FFT (and uses the exact same API), which
1.37 + was a bit too messy and that was ending up duplicating code
1.38 + (might as well use the same FFT everywhere).
1.39 +
1.40 + The algorithm is similar to (and inspired from) Fabrice Bellard's
1.41 + MDCT implementation in FFMPEG, but has differences in signs, ordering
1.42 + and scaling in many places.
1.43 +*/
1.44 +
1.45 +#ifndef MDCT_H
1.46 +#define MDCT_H
1.47 +
1.48 +#include "opus_defines.h"
1.49 +#include "kiss_fft.h"
1.50 +#include "arch.h"
1.51 +
1.52 +typedef struct {
1.53 + int n;
1.54 + int maxshift;
1.55 + const kiss_fft_state *kfft[4];
1.56 + const kiss_twiddle_scalar * OPUS_RESTRICT trig;
1.57 +} mdct_lookup;
1.58 +
1.59 +int clt_mdct_init(mdct_lookup *l,int N, int maxshift);
1.60 +void clt_mdct_clear(mdct_lookup *l);
1.61 +
1.62 +/** Compute a forward MDCT and scale by 4/N, trashes the input array */
1.63 +void clt_mdct_forward(const mdct_lookup *l, kiss_fft_scalar *in,
1.64 + kiss_fft_scalar * OPUS_RESTRICT out,
1.65 + const opus_val16 *window, int overlap, int shift, int stride);
1.66 +
1.67 +/** Compute a backward MDCT (no scaling) and performs weighted overlap-add
1.68 + (scales implicitly by 1/2) */
1.69 +void clt_mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in,
1.70 + kiss_fft_scalar * OPUS_RESTRICT out,
1.71 + const opus_val16 * OPUS_RESTRICT window, int overlap, int shift, int stride);
1.72 +
1.73 +#endif
