Subversion Repositories Kolibri OS

Rev

Go to most recent revision | Blame | Last modification | View Log | RSS feed

  1. /*
  2.  * audio encoder psychoacoustic model
  3.  * Copyright (C) 2008 Konstantin Shishkov
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. #include <string.h>
  23.  
  24. #include "avcodec.h"
  25. #include "psymodel.h"
  26. #include "iirfilter.h"
  27. #include "libavutil/mem.h"
  28.  
  29. extern const FFPsyModel ff_aac_psy_model;
  30.  
  31. av_cold int ff_psy_init(FFPsyContext *ctx, AVCodecContext *avctx, int num_lens,
  32.                         const uint8_t **bands, const int* num_bands,
  33.                         int num_groups, const uint8_t *group_map)
  34. {
  35.     int i, j, k = 0;
  36.  
  37.     ctx->avctx = avctx;
  38.     ctx->ch        = av_mallocz(sizeof(ctx->ch[0]) * avctx->channels * 2);
  39.     ctx->group     = av_mallocz(sizeof(ctx->group[0]) * num_groups);
  40.     ctx->bands     = av_malloc (sizeof(ctx->bands[0])     * num_lens);
  41.     ctx->num_bands = av_malloc (sizeof(ctx->num_bands[0]) * num_lens);
  42.     memcpy(ctx->bands,     bands,     sizeof(ctx->bands[0])     *  num_lens);
  43.     memcpy(ctx->num_bands, num_bands, sizeof(ctx->num_bands[0]) *  num_lens);
  44.  
  45.     /* assign channels to groups (with virtual channels for coupling) */
  46.     for (i = 0; i < num_groups; i++) {
  47.         /* NOTE: Add 1 to handle the AAC chan_config without modification.
  48.          *       This has the side effect of allowing an array of 0s to map
  49.          *       to one channel per group.
  50.          */
  51.         ctx->group[i].num_ch = group_map[i] + 1;
  52.         for (j = 0; j < ctx->group[i].num_ch * 2; j++)
  53.             ctx->group[i].ch[j]  = &ctx->ch[k++];
  54.     }
  55.  
  56.     switch (ctx->avctx->codec_id) {
  57.     case AV_CODEC_ID_AAC:
  58.         ctx->model = &ff_aac_psy_model;
  59.         break;
  60.     }
  61.     if (ctx->model->init)
  62.         return ctx->model->init(ctx);
  63.     return 0;
  64. }
  65.  
  66. FFPsyChannelGroup *ff_psy_find_group(FFPsyContext *ctx, int channel)
  67. {
  68.     int i = 0, ch = 0;
  69.  
  70.     while (ch <= channel)
  71.         ch += ctx->group[i++].num_ch;
  72.  
  73.     return &ctx->group[i-1];
  74. }
  75.  
  76. av_cold void ff_psy_end(FFPsyContext *ctx)
  77. {
  78.     if (ctx->model && ctx->model->end)
  79.         ctx->model->end(ctx);
  80.     av_freep(&ctx->bands);
  81.     av_freep(&ctx->num_bands);
  82.     av_freep(&ctx->group);
  83.     av_freep(&ctx->ch);
  84. }
  85.  
  86. typedef struct FFPsyPreprocessContext{
  87.     AVCodecContext *avctx;
  88.     float stereo_att;
  89.     struct FFIIRFilterCoeffs *fcoeffs;
  90.     struct FFIIRFilterState **fstate;
  91.     struct FFIIRFilterContext fiir;
  92. }FFPsyPreprocessContext;
  93.  
  94. #define FILT_ORDER 4
  95.  
  96. av_cold struct FFPsyPreprocessContext* ff_psy_preprocess_init(AVCodecContext *avctx)
  97. {
  98.     FFPsyPreprocessContext *ctx;
  99.     int i;
  100.     float cutoff_coeff = 0;
  101.     ctx        = av_mallocz(sizeof(FFPsyPreprocessContext));
  102.     ctx->avctx = avctx;
  103.  
  104.     if (avctx->cutoff > 0)
  105.         cutoff_coeff = 2.0 * avctx->cutoff / avctx->sample_rate;
  106.  
  107.     if (!cutoff_coeff && avctx->codec_id == AV_CODEC_ID_AAC)
  108.         cutoff_coeff = 2.0 * AAC_CUTOFF(avctx) / avctx->sample_rate;
  109.  
  110.     if (cutoff_coeff && cutoff_coeff < 0.98)
  111.     ctx->fcoeffs = ff_iir_filter_init_coeffs(avctx, FF_FILTER_TYPE_BUTTERWORTH,
  112.                                              FF_FILTER_MODE_LOWPASS, FILT_ORDER,
  113.                                              cutoff_coeff, 0.0, 0.0);
  114.     if (ctx->fcoeffs) {
  115.         ctx->fstate = av_mallocz(sizeof(ctx->fstate[0]) * avctx->channels);
  116.         for (i = 0; i < avctx->channels; i++)
  117.             ctx->fstate[i] = ff_iir_filter_init_state(FILT_ORDER);
  118.     }
  119.  
  120.     ff_iir_filter_init(&ctx->fiir);
  121.  
  122.     return ctx;
  123. }
  124.  
  125. void ff_psy_preprocess(struct FFPsyPreprocessContext *ctx, float **audio, int channels)
  126. {
  127.     int ch;
  128.     int frame_size = ctx->avctx->frame_size;
  129.     FFIIRFilterContext *iir = &ctx->fiir;
  130.  
  131.     if (ctx->fstate) {
  132.         for (ch = 0; ch < channels; ch++)
  133.             iir->filter_flt(ctx->fcoeffs, ctx->fstate[ch], frame_size,
  134.                             &audio[ch][frame_size], 1, &audio[ch][frame_size], 1);
  135.     }
  136. }
  137.  
  138. av_cold void ff_psy_preprocess_end(struct FFPsyPreprocessContext *ctx)
  139. {
  140.     int i;
  141.     ff_iir_filter_free_coeffs(ctx->fcoeffs);
  142.     if (ctx->fstate)
  143.         for (i = 0; i < ctx->avctx->channels; i++)
  144.             ff_iir_filter_free_state(ctx->fstate[i]);
  145.     av_freep(&ctx->fstate);
  146.     av_free(ctx);
  147. }
  148.