diff options
author | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2011-09-14 05:21:18 +0400 |
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committer | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2011-09-14 05:21:18 +0400 |
commit | c37499090b68e03cbd102afa2ac79f6db7c39247 (patch) | |
tree | 84fcb16201cbddda4241386183beb8a43342435f /celt/mdct.h | |
parent | 92675068a425677855c0a379efc4f10e51ee9595 (diff) |
renames the libcelt/ directory to celt/
Diffstat (limited to 'celt/mdct.h')
-rw-r--r-- | celt/mdct.h | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/celt/mdct.h b/celt/mdct.h new file mode 100644 index 00000000..bba627cc --- /dev/null +++ b/celt/mdct.h @@ -0,0 +1,67 @@ +/* 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 FOUNDATION 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 "kiss_fft.h" +#include "arch.h" + +typedef struct { + int n; + int maxshift; + const kiss_fft_state *kfft[4]; + const kiss_twiddle_scalar * restrict trig; +} mdct_lookup; + +int clt_mdct_init(mdct_lookup *l,int N, int maxshift); +void clt_mdct_clear(mdct_lookup *l); + +/** Compute a forward MDCT and scale by 4/N, trashes the input array */ +void clt_mdct_forward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar *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 mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar *out, + const opus_val16 * restrict window, int overlap, int shift, int stride); + +#endif |