mirror of https://github.com/FFmpeg/FFmpeg.git
Originally committed as revision 19796 to svn://svn.ffmpeg.org/ffmpeg/trunkrelease/0.6
Benjamin Larsson
16 years ago
parent
b057170f32
commit
0e1baedec3
4 changed files with 165 additions and 64 deletions
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/*
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* Atrac common functions |
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* Copyright (c) 2006-2008 Maxim Poliakovski |
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* Copyright (c) 2006-2008 Benjamin Larsson |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/**
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* @file libavcodec/atrac.c |
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*/ |
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#include <math.h> |
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#include <stddef.h> |
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#include <stdio.h> |
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#include "avcodec.h" |
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#include "dsputil.h" |
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float sf_table[64]; |
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float qmf_window[48]; |
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static const float qmf_48tap_half[24] = { |
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-0.00001461907, -0.00009205479,-0.000056157569,0.00030117269, |
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0.0002422519, -0.00085293897,-0.0005205574, 0.0020340169, |
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0.00078333891, -0.0042153862, -0.00075614988, 0.0078402944, |
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-0.000061169922,-0.01344162, 0.0024626821, 0.021736089, |
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-0.007801671, -0.034090221, 0.01880949, 0.054326009, |
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-0.043596379, -0.099384367, 0.13207909, 0.46424159 |
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}; |
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/**
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* Generate common tables |
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*/ |
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void atrac_generate_tables(void) |
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{ |
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int i; |
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float s; |
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/* Generate scale factors */ |
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if (!sf_table[63]) |
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for (i=0 ; i<64 ; i++) |
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sf_table[i] = pow(2.0, (i - 15) / 3.0); |
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/* Generate the QMF window. */ |
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if (!qmf_window[47]) |
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for (i=0 ; i<24; i++) { |
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s = qmf_48tap_half[i] * 2.0; |
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qmf_window[i] = qmf_window[47 - i] = s; |
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} |
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} |
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/**
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* Quadrature mirror synthesis filter. |
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* |
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* @param inlo lower part of spectrum |
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* @param inhi higher part of spectrum |
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* @param nIn size of spectrum buffer |
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* @param pOut out buffer |
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* @param delayBuf delayBuf buffer |
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* @param temp temp buffer |
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*/ |
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void atrac_iqmf (float *inlo, float *inhi, unsigned int nIn, float *pOut, float *delayBuf, float *temp) |
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{ |
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int i, j; |
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float *p1, *p3; |
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memcpy(temp, delayBuf, 46*sizeof(float)); |
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p3 = temp + 46; |
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/* loop1 */ |
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for(i=0; i<nIn; i+=2){ |
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p3[2*i+0] = inlo[i ] + inhi[i ]; |
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p3[2*i+1] = inlo[i ] - inhi[i ]; |
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p3[2*i+2] = inlo[i+1] + inhi[i+1]; |
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p3[2*i+3] = inlo[i+1] - inhi[i+1]; |
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} |
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/* loop2 */ |
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p1 = temp; |
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for (j = nIn; j != 0; j--) { |
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float s1 = 0.0; |
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float s2 = 0.0; |
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for (i = 0; i < 48; i += 2) { |
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s1 += p1[i] * qmf_window[i]; |
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s2 += p1[i+1] * qmf_window[i+1]; |
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} |
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pOut[0] = s2; |
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pOut[1] = s1; |
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p1 += 2; |
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pOut += 2; |
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} |
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/* Update the delay buffer. */ |
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memcpy(delayBuf, temp + nIn*2, 46*sizeof(float)); |
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} |
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@ -0,0 +1,38 @@ |
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/*
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* Atrac common data |
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* Copyright (c) 2009 Maxim Poliakovski |
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* Copyright (c) 2009 Benjamin Larsson |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/**
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* @file libavcodec/atrac1data.h |
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* Atrac 1 compatible decoder data |
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*/ |
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#ifndef AVCODEC_ATRAC_H |
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#define AVCODEC_ATRAC_H |
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extern float sf_table[64]; |
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extern float qmf_window[48]; |
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void atrac_generate_tables(void); |
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void atrac_iqmf (float *inlo, float *inhi, unsigned int nIn, float *pOut, float *delayBuf, float *temp); |
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#endif /* AVCODEC_ATRAC_H */ |
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