media/libopus/celt/mdct.h@b8a032363ba2 (annotated)
media/libopus/celt/mdct.h
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /* Copyright (c) 2007-2008 CSIRO |
| michael@0 | 2 | Copyright (c) 2007-2008 Xiph.Org Foundation |
| michael@0 | 3 | Written by Jean-Marc Valin */ |
| michael@0 | 4 | /* |
| michael@0 | 5 | Redistribution and use in source and binary forms, with or without |
| michael@0 | 6 | modification, are permitted provided that the following conditions |
| michael@0 | 7 | are met: |
| michael@0 | 8 | |
| michael@0 | 9 | - Redistributions of source code must retain the above copyright |
| michael@0 | 10 | notice, this list of conditions and the following disclaimer. |
| michael@0 | 11 | |
| michael@0 | 12 | - Redistributions in binary form must reproduce the above copyright |
| michael@0 | 13 | notice, this list of conditions and the following disclaimer in the |
| michael@0 | 14 | documentation and/or other materials provided with the distribution. |
| michael@0 | 15 | |
| michael@0 | 16 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| michael@0 | 17 | ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| michael@0 | 18 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| michael@0 | 19 | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER |
| michael@0 | 20 | OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| michael@0 | 21 | EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| michael@0 | 22 | PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| michael@0 | 23 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| michael@0 | 24 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| michael@0 | 25 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| michael@0 | 26 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| michael@0 | 27 | */ |
| michael@0 | 28 | |
| michael@0 | 29 | /* This is a simple MDCT implementation that uses a N/4 complex FFT |
| michael@0 | 30 | to do most of the work. It should be relatively straightforward to |
| michael@0 | 31 | plug in pretty much and FFT here. |
| michael@0 | 32 | |
| michael@0 | 33 | This replaces the Vorbis FFT (and uses the exact same API), which |
| michael@0 | 34 | was a bit too messy and that was ending up duplicating code |
| michael@0 | 35 | (might as well use the same FFT everywhere). |
| michael@0 | 36 | |
| michael@0 | 37 | The algorithm is similar to (and inspired from) Fabrice Bellard's |
| michael@0 | 38 | MDCT implementation in FFMPEG, but has differences in signs, ordering |
| michael@0 | 39 | and scaling in many places. |
| michael@0 | 40 | */ |
| michael@0 | 41 | |
| michael@0 | 42 | #ifndef MDCT_H |
| michael@0 | 43 | #define MDCT_H |
| michael@0 | 44 | |
| michael@0 | 45 | #include "opus_defines.h" |
| michael@0 | 46 | #include "kiss_fft.h" |
| michael@0 | 47 | #include "arch.h" |
| michael@0 | 48 | |
| michael@0 | 49 | typedef struct { |
| michael@0 | 50 | int n; |
| michael@0 | 51 | int maxshift; |
| michael@0 | 52 | const kiss_fft_state *kfft[4]; |
| michael@0 | 53 | const kiss_twiddle_scalar * OPUS_RESTRICT trig; |
| michael@0 | 54 | } mdct_lookup; |
| michael@0 | 55 | |
| michael@0 | 56 | int clt_mdct_init(mdct_lookup *l,int N, int maxshift); |
| michael@0 | 57 | void clt_mdct_clear(mdct_lookup *l); |
| michael@0 | 58 | |
| michael@0 | 59 | /** Compute a forward MDCT and scale by 4/N, trashes the input array */ |
| michael@0 | 60 | void clt_mdct_forward(const mdct_lookup *l, kiss_fft_scalar *in, |
| michael@0 | 61 | kiss_fft_scalar * OPUS_RESTRICT out, |
| michael@0 | 62 | const opus_val16 *window, int overlap, int shift, int stride); |
| michael@0 | 63 | |
| michael@0 | 64 | /** Compute a backward MDCT (no scaling) and performs weighted overlap-add |
| michael@0 | 65 | (scales implicitly by 1/2) */ |
| michael@0 | 66 | void clt_mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in, |
| michael@0 | 67 | kiss_fft_scalar * OPUS_RESTRICT out, |
| michael@0 | 68 | const opus_val16 * OPUS_RESTRICT window, int overlap, int shift, int stride); |
| michael@0 | 69 | |
| michael@0 | 70 | #endif |
