Libav
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00001 /* 00002 * audio encoder psychoacoustic model 00003 * Copyright (C) 2008 Konstantin Shishkov 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00022 #include "avcodec.h" 00023 #include "psymodel.h" 00024 #include "iirfilter.h" 00025 00026 extern const FFPsyModel ff_aac_psy_model; 00027 00028 av_cold int ff_psy_init(FFPsyContext *ctx, AVCodecContext *avctx, 00029 int num_lens, 00030 const uint8_t **bands, const int* num_bands) 00031 { 00032 ctx->avctx = avctx; 00033 ctx->psy_bands = av_mallocz(sizeof(FFPsyBand) * PSY_MAX_BANDS * avctx->channels); 00034 ctx->bands = av_malloc (sizeof(ctx->bands[0]) * num_lens); 00035 ctx->num_bands = av_malloc (sizeof(ctx->num_bands[0]) * num_lens); 00036 memcpy(ctx->bands, bands, sizeof(ctx->bands[0]) * num_lens); 00037 memcpy(ctx->num_bands, num_bands, sizeof(ctx->num_bands[0]) * num_lens); 00038 switch (ctx->avctx->codec_id) { 00039 case CODEC_ID_AAC: 00040 ctx->model = &ff_aac_psy_model; 00041 break; 00042 } 00043 if (ctx->model->init) 00044 return ctx->model->init(ctx); 00045 return 0; 00046 } 00047 00048 FFPsyWindowInfo ff_psy_suggest_window(FFPsyContext *ctx, 00049 const int16_t *audio, const int16_t *la, 00050 int channel, int prev_type) 00051 { 00052 return ctx->model->window(ctx, audio, la, channel, prev_type); 00053 } 00054 00055 void ff_psy_set_band_info(FFPsyContext *ctx, int channel, 00056 const float *coeffs, FFPsyWindowInfo *wi) 00057 { 00058 ctx->model->analyze(ctx, channel, coeffs, wi); 00059 } 00060 00061 av_cold void ff_psy_end(FFPsyContext *ctx) 00062 { 00063 if (ctx->model->end) 00064 ctx->model->end(ctx); 00065 av_freep(&ctx->bands); 00066 av_freep(&ctx->num_bands); 00067 av_freep(&ctx->psy_bands); 00068 } 00069 00070 typedef struct FFPsyPreprocessContext{ 00071 AVCodecContext *avctx; 00072 float stereo_att; 00073 struct FFIIRFilterCoeffs *fcoeffs; 00074 struct FFIIRFilterState **fstate; 00075 }FFPsyPreprocessContext; 00076 00077 #define FILT_ORDER 4 00078 00079 av_cold struct FFPsyPreprocessContext* ff_psy_preprocess_init(AVCodecContext *avctx) 00080 { 00081 FFPsyPreprocessContext *ctx; 00082 int i; 00083 float cutoff_coeff = 0; 00084 ctx = av_mallocz(sizeof(FFPsyPreprocessContext)); 00085 ctx->avctx = avctx; 00086 00087 if (avctx->cutoff > 0) 00088 cutoff_coeff = 2.0 * avctx->cutoff / avctx->sample_rate; 00089 00090 if (cutoff_coeff) 00091 ctx->fcoeffs = ff_iir_filter_init_coeffs(FF_FILTER_TYPE_BUTTERWORTH, FF_FILTER_MODE_LOWPASS, 00092 FILT_ORDER, cutoff_coeff, 0.0, 0.0); 00093 if (ctx->fcoeffs) { 00094 ctx->fstate = av_mallocz(sizeof(ctx->fstate[0]) * avctx->channels); 00095 for (i = 0; i < avctx->channels; i++) 00096 ctx->fstate[i] = ff_iir_filter_init_state(FILT_ORDER); 00097 } 00098 return ctx; 00099 } 00100 00101 void ff_psy_preprocess(struct FFPsyPreprocessContext *ctx, 00102 const int16_t *audio, int16_t *dest, 00103 int tag, int channels) 00104 { 00105 int ch, i; 00106 if (ctx->fstate) { 00107 for (ch = 0; ch < channels; ch++) 00108 ff_iir_filter(ctx->fcoeffs, ctx->fstate[tag+ch], ctx->avctx->frame_size, 00109 audio + ch, ctx->avctx->channels, 00110 dest + ch, ctx->avctx->channels); 00111 } else { 00112 for (ch = 0; ch < channels; ch++) 00113 for (i = 0; i < ctx->avctx->frame_size; i++) 00114 dest[i*ctx->avctx->channels + ch] = audio[i*ctx->avctx->channels + ch]; 00115 } 00116 } 00117 00118 av_cold void ff_psy_preprocess_end(struct FFPsyPreprocessContext *ctx) 00119 { 00120 int i; 00121 ff_iir_filter_free_coeffs(ctx->fcoeffs); 00122 if (ctx->fstate) 00123 for (i = 0; i < ctx->avctx->channels; i++) 00124 ff_iir_filter_free_state(ctx->fstate[i]); 00125 av_freep(&ctx->fstate); 00126 } 00127