mirror of
https://github.com/godotengine/godot.git
synced 2025-10-31 13:41:03 +00:00
71 lines
2.8 KiB
C
71 lines
2.8 KiB
C
|
/* Copyright (c) 2007-2008 CSIRO
|
||
|
|
Copyright (c) 2007-2008 Xiph.Org Foundation
|
||
|
|
Written by Jean-Marc Valin */
|
||
|
|
/*
|
||
|
|
Redistribution and use in source and binary forms, with or without
|
||
|
|
modification, are permitted provided that the following conditions
|
||
|
|
are met:
|
||
|
|
|
||
|
|
- Redistributions of source code must retain the above copyright
|
||
|
|
notice, this list of conditions and the following disclaimer.
|
||
|
|
|
||
|
|
- Redistributions in binary form must reproduce the above copyright
|
||
|
|
notice, this list of conditions and the following disclaimer in the
|
||
|
|
documentation and/or other materials provided with the distribution.
|
||
|
|
|
||
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||
|
|
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||
|
|
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
||
|
|
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
|
||
|
|
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
|
||
|
|
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
|
||
|
|
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
|
||
|
|
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
|
||
|
|
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
|
||
|
|
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
||
|
|
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* This is a simple MDCT implementation that uses a N/4 complex FFT
|
||
|
|
to do most of the work. It should be relatively straightforward to
|
||
|
|
plug in pretty much and FFT here.
|
||
|
|
|
||
|
|
This replaces the Vorbis FFT (and uses the exact same API), which
|
||
|
|
was a bit too messy and that was ending up duplicating code
|
||
|
|
(might as well use the same FFT everywhere).
|
||
|
|
|
||
|
|
The algorithm is similar to (and inspired from) Fabrice Bellard's
|
||
|
|
MDCT implementation in FFMPEG, but has differences in signs, ordering
|
||
|
|
and scaling in many places.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef MDCT_H
|
||
|
|
#define MDCT_H
|
||
|
|
|
||
|
|
#include "opus_defines.h"
|
||
|
|
#include "kiss_fft.h"
|
||
|
|
#include "arch.h"
|
||
|
|
|
||
|
|
typedef struct {
|
||
|
|
int n;
|
||
|
|
int maxshift;
|
||
|
|
const kiss_fft_state *kfft[4];
|
||
|
|
const kiss_twiddle_scalar * OPUS_RESTRICT trig;
|
||
|
|
} celt_mdct_lookup;
|
||
|
|
|
||
|
|
int clt_mdct_init(celt_mdct_lookup *l,int N, int maxshift);
|
||
|
|
void clt_mdct_clear(celt_mdct_lookup *l);
|
||
|
|
|
||
|
|
/** Compute a forward MDCT and scale by 4/N, trashes the input array */
|
||
|
|
void clt_mdct_forward(const celt_mdct_lookup *l, kiss_fft_scalar *in,
|
||
|
|
kiss_fft_scalar * OPUS_RESTRICT out,
|
||
|
|
const opus_val16 *window, int overlap, int shift, int stride);
|
||
|
|
|
||
|
|
/** Compute a backward MDCT (no scaling) and performs weighted overlap-add
|
||
|
|
(scales implicitly by 1/2) */
|
||
|
|
void clt_mdct_backward(const celt_mdct_lookup *l, kiss_fft_scalar *in,
|
||
|
|
kiss_fft_scalar * OPUS_RESTRICT out,
|
||
|
|
const opus_val16 * OPUS_RESTRICT window, int overlap, int shift, int stride);
|
||
|
|
|
||
|
|
#endif
|