libavresample/audio_mix_matrix.c
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 /*
  * Copyright (C) 2011 Michael Niedermayer (michaelni@gmx.at)
  * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com>
  *
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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
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
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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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * 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
  */
 
 #include <stdint.h>
 
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 #include "libavutil/common.h"
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 #include "libavutil/libm.h"
 #include "libavutil/samplefmt.h"
 #include "avresample.h"
 #include "internal.h"
 #include "audio_data.h"
 #include "audio_mix.h"
 
 /* channel positions */
 #define FRONT_LEFT              0
 #define FRONT_RIGHT             1
 #define FRONT_CENTER            2
 #define LOW_FREQUENCY           3
 #define BACK_LEFT               4
 #define BACK_RIGHT              5
 #define FRONT_LEFT_OF_CENTER    6
 #define FRONT_RIGHT_OF_CENTER   7
 #define BACK_CENTER             8
 #define SIDE_LEFT               9
 #define SIDE_RIGHT             10
 #define TOP_CENTER             11
 #define TOP_FRONT_LEFT         12
 #define TOP_FRONT_CENTER       13
 #define TOP_FRONT_RIGHT        14
 #define TOP_BACK_LEFT          15
 #define TOP_BACK_CENTER        16
 #define TOP_BACK_RIGHT         17
 #define STEREO_LEFT            29
 #define STEREO_RIGHT           30
 #define WIDE_LEFT              31
 #define WIDE_RIGHT             32
 #define SURROUND_DIRECT_LEFT   33
 #define SURROUND_DIRECT_RIGHT  34
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 #define LOW_FREQUENCY_2        35
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 #define SQRT3_2      1.22474487139158904909  /* sqrt(3/2) */
 
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 static av_always_inline int even(uint64_t layout)
 {
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     return (!layout || !!(layout & (layout - 1)));
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 }
 
 static int sane_layout(uint64_t layout)
 {
     /* check that there is at least 1 front speaker */
     if (!(layout & AV_CH_LAYOUT_SURROUND))
         return 0;
 
     /* check for left/right symmetry */
     if (!even(layout & (AV_CH_FRONT_LEFT           | AV_CH_FRONT_RIGHT))           ||
         !even(layout & (AV_CH_SIDE_LEFT            | AV_CH_SIDE_RIGHT))            ||
         !even(layout & (AV_CH_BACK_LEFT            | AV_CH_BACK_RIGHT))            ||
         !even(layout & (AV_CH_FRONT_LEFT_OF_CENTER | AV_CH_FRONT_RIGHT_OF_CENTER)) ||
         !even(layout & (AV_CH_TOP_FRONT_LEFT       | AV_CH_TOP_FRONT_RIGHT))       ||
         !even(layout & (AV_CH_TOP_BACK_LEFT        | AV_CH_TOP_BACK_RIGHT))        ||
         !even(layout & (AV_CH_STEREO_LEFT          | AV_CH_STEREO_RIGHT))          ||
         !even(layout & (AV_CH_WIDE_LEFT            | AV_CH_WIDE_RIGHT))            ||
         !even(layout & (AV_CH_SURROUND_DIRECT_LEFT | AV_CH_SURROUND_DIRECT_RIGHT)))
         return 0;
 
     return 1;
 }
 
 int avresample_build_matrix(uint64_t in_layout, uint64_t out_layout,
                             double center_mix_level, double surround_mix_level,
                             double lfe_mix_level, int normalize,
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                             double *matrix_out, int stride,
                             enum AVMatrixEncoding matrix_encoding)
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 {
     int i, j, out_i, out_j;
     double matrix[64][64] = {{0}};
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     int64_t unaccounted;
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     double maxcoef = 0;
     int in_channels, out_channels;
 
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     if ((out_layout & AV_CH_LAYOUT_STEREO_DOWNMIX) == AV_CH_LAYOUT_STEREO_DOWNMIX) {
         out_layout = AV_CH_LAYOUT_STEREO;
     }
 
     unaccounted = in_layout & ~out_layout;
 
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     in_channels  = av_get_channel_layout_nb_channels( in_layout);
     out_channels = av_get_channel_layout_nb_channels(out_layout);
 
     memset(matrix_out, 0, out_channels * stride * sizeof(*matrix_out));
 
     /* check if layouts are supported */
     if (!in_layout || in_channels > AVRESAMPLE_MAX_CHANNELS)
         return AVERROR(EINVAL);
     if (!out_layout || out_channels > AVRESAMPLE_MAX_CHANNELS)
         return AVERROR(EINVAL);
 
     /* check if layouts are unbalanced or abnormal */
     if (!sane_layout(in_layout) || !sane_layout(out_layout))
         return AVERROR_PATCHWELCOME;
 
     /* route matching input/output channels */
     for (i = 0; i < 64; i++) {
         if (in_layout & out_layout & (1ULL << i))
             matrix[i][i] = 1.0;
     }
 
     /* mix front center to front left/right */
     if (unaccounted & AV_CH_FRONT_CENTER) {
         if ((out_layout & AV_CH_LAYOUT_STEREO) == AV_CH_LAYOUT_STEREO) {
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             if ((in_layout & AV_CH_LAYOUT_STEREO) == AV_CH_LAYOUT_STEREO) {
                 matrix[FRONT_LEFT ][FRONT_CENTER] += center_mix_level;
                 matrix[FRONT_RIGHT][FRONT_CENTER] += center_mix_level;
             } else {
                 matrix[FRONT_LEFT ][FRONT_CENTER] += M_SQRT1_2;
                 matrix[FRONT_RIGHT][FRONT_CENTER] += M_SQRT1_2;
             }
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         } else
             return AVERROR_PATCHWELCOME;
     }
     /* mix front left/right to center */
     if (unaccounted & AV_CH_LAYOUT_STEREO) {
         if (out_layout & AV_CH_FRONT_CENTER) {
             matrix[FRONT_CENTER][FRONT_LEFT ] += M_SQRT1_2;
             matrix[FRONT_CENTER][FRONT_RIGHT] += M_SQRT1_2;
             /* mix left/right/center to center */
             if (in_layout & AV_CH_FRONT_CENTER)
                 matrix[FRONT_CENTER][FRONT_CENTER] = center_mix_level * M_SQRT2;
         } else
             return AVERROR_PATCHWELCOME;
     }
     /* mix back center to back, side, or front */
     if (unaccounted & AV_CH_BACK_CENTER) {
         if (out_layout & AV_CH_BACK_LEFT) {
             matrix[BACK_LEFT ][BACK_CENTER] += M_SQRT1_2;
             matrix[BACK_RIGHT][BACK_CENTER] += M_SQRT1_2;
         } else if (out_layout & AV_CH_SIDE_LEFT) {
             matrix[SIDE_LEFT ][BACK_CENTER] += M_SQRT1_2;
             matrix[SIDE_RIGHT][BACK_CENTER] += M_SQRT1_2;
         } else if (out_layout & AV_CH_FRONT_LEFT) {
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             if (matrix_encoding == AV_MATRIX_ENCODING_DOLBY ||
                 matrix_encoding == AV_MATRIX_ENCODING_DPLII) {
                 if (unaccounted & (AV_CH_BACK_LEFT | AV_CH_SIDE_LEFT)) {
                     matrix[FRONT_LEFT ][BACK_CENTER] -= surround_mix_level * M_SQRT1_2;
                     matrix[FRONT_RIGHT][BACK_CENTER] += surround_mix_level * M_SQRT1_2;
                 } else {
                     matrix[FRONT_LEFT ][BACK_CENTER] -= surround_mix_level;
                     matrix[FRONT_RIGHT][BACK_CENTER] += surround_mix_level;
                 }
             } else {
                 matrix[FRONT_LEFT ][BACK_CENTER] += surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_RIGHT][BACK_CENTER] += surround_mix_level * M_SQRT1_2;
             }
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         } else if (out_layout & AV_CH_FRONT_CENTER) {
             matrix[FRONT_CENTER][BACK_CENTER] += surround_mix_level * M_SQRT1_2;
         } else
             return AVERROR_PATCHWELCOME;
     }
     /* mix back left/right to back center, side, or front */
     if (unaccounted & AV_CH_BACK_LEFT) {
         if (out_layout & AV_CH_BACK_CENTER) {
             matrix[BACK_CENTER][BACK_LEFT ] += M_SQRT1_2;
             matrix[BACK_CENTER][BACK_RIGHT] += M_SQRT1_2;
         } else if (out_layout & AV_CH_SIDE_LEFT) {
             /* if side channels do not exist in the input, just copy back
                channels to side channels, otherwise mix back into side */
             if (in_layout & AV_CH_SIDE_LEFT) {
                 matrix[SIDE_LEFT ][BACK_LEFT ] += M_SQRT1_2;
                 matrix[SIDE_RIGHT][BACK_RIGHT] += M_SQRT1_2;
             } else {
                 matrix[SIDE_LEFT ][BACK_LEFT ] += 1.0;
                 matrix[SIDE_RIGHT][BACK_RIGHT] += 1.0;
             }
         } else if (out_layout & AV_CH_FRONT_LEFT) {
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             if (matrix_encoding == AV_MATRIX_ENCODING_DOLBY) {
                 matrix[FRONT_LEFT ][BACK_LEFT ] -= surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_LEFT ][BACK_RIGHT] -= surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_RIGHT][BACK_LEFT ] += surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_RIGHT][BACK_RIGHT] += surround_mix_level * M_SQRT1_2;
             } else if (matrix_encoding == AV_MATRIX_ENCODING_DPLII) {
                 matrix[FRONT_LEFT ][BACK_LEFT ] -= surround_mix_level * SQRT3_2;
                 matrix[FRONT_LEFT ][BACK_RIGHT] -= surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_RIGHT][BACK_LEFT ] += surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_RIGHT][BACK_RIGHT] += surround_mix_level * SQRT3_2;
             } else {
                 matrix[FRONT_LEFT ][BACK_LEFT ] += surround_mix_level;
                 matrix[FRONT_RIGHT][BACK_RIGHT] += surround_mix_level;
             }
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         } else if (out_layout & AV_CH_FRONT_CENTER) {
             matrix[FRONT_CENTER][BACK_LEFT ] += surround_mix_level * M_SQRT1_2;
             matrix[FRONT_CENTER][BACK_RIGHT] += surround_mix_level * M_SQRT1_2;
         } else
             return AVERROR_PATCHWELCOME;
     }
     /* mix side left/right into back or front */
     if (unaccounted & AV_CH_SIDE_LEFT) {
         if (out_layout & AV_CH_BACK_LEFT) {
             /* if back channels do not exist in the input, just copy side
                channels to back channels, otherwise mix side into back */
             if (in_layout & AV_CH_BACK_LEFT) {
                 matrix[BACK_LEFT ][SIDE_LEFT ] += M_SQRT1_2;
                 matrix[BACK_RIGHT][SIDE_RIGHT] += M_SQRT1_2;
             } else {
                 matrix[BACK_LEFT ][SIDE_LEFT ] += 1.0;
                 matrix[BACK_RIGHT][SIDE_RIGHT] += 1.0;
             }
         } else if (out_layout & AV_CH_BACK_CENTER) {
             matrix[BACK_CENTER][SIDE_LEFT ] += M_SQRT1_2;
             matrix[BACK_CENTER][SIDE_RIGHT] += M_SQRT1_2;
         } else if (out_layout & AV_CH_FRONT_LEFT) {
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             if (matrix_encoding == AV_MATRIX_ENCODING_DOLBY) {
                 matrix[FRONT_LEFT ][SIDE_LEFT ] -= surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_LEFT ][SIDE_RIGHT] -= surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_RIGHT][SIDE_LEFT ] += surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_RIGHT][SIDE_RIGHT] += surround_mix_level * M_SQRT1_2;
             } else if (matrix_encoding == AV_MATRIX_ENCODING_DPLII) {
                 matrix[FRONT_LEFT ][SIDE_LEFT ] -= surround_mix_level * SQRT3_2;
                 matrix[FRONT_LEFT ][SIDE_RIGHT] -= surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_RIGHT][SIDE_LEFT ] += surround_mix_level * M_SQRT1_2;
                 matrix[FRONT_RIGHT][SIDE_RIGHT] += surround_mix_level * SQRT3_2;
             } else {
                 matrix[FRONT_LEFT ][SIDE_LEFT ] += surround_mix_level;
                 matrix[FRONT_RIGHT][SIDE_RIGHT] += surround_mix_level;
             }
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         } else if (out_layout & AV_CH_FRONT_CENTER) {
             matrix[FRONT_CENTER][SIDE_LEFT ] += surround_mix_level * M_SQRT1_2;
             matrix[FRONT_CENTER][SIDE_RIGHT] += surround_mix_level * M_SQRT1_2;
         } else
             return AVERROR_PATCHWELCOME;
     }
     /* mix left-of-center/right-of-center into front left/right or center */
     if (unaccounted & AV_CH_FRONT_LEFT_OF_CENTER) {
         if (out_layout & AV_CH_FRONT_LEFT) {
             matrix[FRONT_LEFT ][FRONT_LEFT_OF_CENTER ] += 1.0;
             matrix[FRONT_RIGHT][FRONT_RIGHT_OF_CENTER] += 1.0;
         } else if (out_layout & AV_CH_FRONT_CENTER) {
             matrix[FRONT_CENTER][FRONT_LEFT_OF_CENTER ] += M_SQRT1_2;
             matrix[FRONT_CENTER][FRONT_RIGHT_OF_CENTER] += M_SQRT1_2;
         } else
             return AVERROR_PATCHWELCOME;
     }
     /* mix LFE into front left/right or center */
     if (unaccounted & AV_CH_LOW_FREQUENCY) {
         if (out_layout & AV_CH_FRONT_CENTER) {
             matrix[FRONT_CENTER][LOW_FREQUENCY] += lfe_mix_level;
         } else if (out_layout & AV_CH_FRONT_LEFT) {
             matrix[FRONT_LEFT ][LOW_FREQUENCY] += lfe_mix_level * M_SQRT1_2;
             matrix[FRONT_RIGHT][LOW_FREQUENCY] += lfe_mix_level * M_SQRT1_2;
         } else
             return AVERROR_PATCHWELCOME;
     }
 
     /* transfer internal matrix to output matrix and calculate maximum
        per-channel coefficient sum */
     for (out_i = i = 0; out_i < out_channels && i < 64; i++) {
         double sum = 0;
         for (out_j = j = 0; out_j < in_channels && j < 64; j++) {
             matrix_out[out_i * stride + out_j] = matrix[i][j];
             sum += fabs(matrix[i][j]);
             if (in_layout & (1ULL << j))
                 out_j++;
         }
         maxcoef = FFMAX(maxcoef, sum);
         if (out_layout & (1ULL << i))
             out_i++;
     }
 
     /* normalize */
     if (normalize && maxcoef > 1.0) {
         for (i = 0; i < out_channels; i++)
             for (j = 0; j < in_channels; j++)
                 matrix_out[i * stride + j] /= maxcoef;
     }
 
     return 0;
 }