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Diffstat (limited to 'libavcodec/psymodel.h')
| -rw-r--r-- | libavcodec/psymodel.h | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/libavcodec/psymodel.h b/libavcodec/psymodel.h new file mode 100644 index 0000000000..5bcf556f0b --- /dev/null +++ b/libavcodec/psymodel.h @@ -0,0 +1,158 @@ +/* + * audio encoder psychoacoustic model + * Copyright (C) 2008 Konstantin Shishkov + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * 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. + * + * FFmpeg is distributed in the hope that it will be useful, + * 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 + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef AVCODEC_PSYMODEL_H +#define AVCODEC_PSYMODEL_H + +#include "avcodec.h" + +/** maximum possible number of bands */ +#define PSY_MAX_BANDS 128 + +/** + * single band psychoacoustic information + */ +typedef struct FFPsyBand{ + int bits; + float energy; + float threshold; + float distortion; + float perceptual_weight; +}FFPsyBand; + +/** + * windowing related information + */ +typedef struct FFPsyWindowInfo{ + int window_type[3]; ///< window type (short/long/transitional, etc.) - current, previous and next + int window_shape; ///< window shape (sine/KBD/whatever) + int num_windows; ///< number of windows in a frame + int grouping[8]; ///< window grouping (for e.g. AAC) + int *window_sizes; ///< sequence of window sizes inside one frame (for eg. WMA) +}FFPsyWindowInfo; + +/** + * context used by psychoacoustic model + */ +typedef struct FFPsyContext{ + AVCodecContext *avctx; ///< encoder context + const struct FFPsyModel *model; ///< encoder-specific model functions + + FFPsyBand *psy_bands; ///< frame bands information + + uint8_t **bands; ///< scalefactor band sizes for possible frame sizes + int *num_bands; ///< number of scalefactor bands for possible frame sizes + int num_lens; ///< number of scalefactor band sets + + void* model_priv_data; ///< psychoacoustic model implementation private data +}FFPsyContext; + +/** + * codec-specific psychoacoustic model implementation + */ +typedef struct FFPsyModel { + const char *name; + int (*init) (FFPsyContext *apc); + FFPsyWindowInfo (*window)(FFPsyContext *ctx, const int16_t *audio, const int16_t *la, int channel, int prev_type); + void (*analyze)(FFPsyContext *ctx, int channel, const float *coeffs, FFPsyWindowInfo *wi); + void (*end) (FFPsyContext *apc); +}FFPsyModel; + +/** + * Initialize psychoacoustic model. + * + * @param ctx model context + * @param avctx codec context + * @param num_lens number of possible frame lengths + * @param bands scalefactor band lengths for all frame lengths + * @param num_bands number of scalefactor bands for all frame lengths + * + * @return zero if successful, a negative value if not + */ +av_cold int ff_psy_init(FFPsyContext *ctx, AVCodecContext *avctx, + int num_lens, + const uint8_t **bands, const int* num_bands); + +/** + * Suggest window sequence for channel. + * + * @param ctx model context + * @param audio samples for the current frame + * @param la lookahead samples (NULL when unavailable) + * @param channel number of channel element to analyze + * @param prev_type previous window type + * + * @return suggested window information in a structure + */ +FFPsyWindowInfo ff_psy_suggest_window(FFPsyContext *ctx, + const int16_t *audio, const int16_t *la, + int channel, int prev_type); + + +/** + * Perform psychoacoustic analysis and set band info (threshold, energy). + * + * @param ctx model context + * @param channel audio channel number + * @param coeffs pointer to the transformed coefficients + * @param wi window information + */ +void ff_psy_set_band_info(FFPsyContext *ctx, int channel, const float *coeffs, + FFPsyWindowInfo *wi); + +/** + * Cleanup model context at the end. + * + * @param ctx model context + */ +av_cold void ff_psy_end(FFPsyContext *ctx); + + +/************************************************************************** + * Audio preprocessing stuff. * + * This should be moved into some audio filter eventually. * + **************************************************************************/ +struct FFPsyPreprocessContext; + +/** + * psychoacoustic model audio preprocessing initialization + */ +av_cold struct FFPsyPreprocessContext* ff_psy_preprocess_init(AVCodecContext *avctx); + +/** + * Preprocess several channel in audio frame in order to compress it better. + * + * @param ctx preprocessing context + * @param audio samples to preprocess + * @param dest place to put filtered samples + * @param tag channel number + * @param channels number of channel to preprocess (some additional work may be done on stereo pair) + */ +void ff_psy_preprocess(struct FFPsyPreprocessContext *ctx, + const int16_t *audio, int16_t *dest, + int tag, int channels); + +/** + * Cleanup audio preprocessing module. + */ +av_cold void ff_psy_preprocess_end(struct FFPsyPreprocessContext *ctx); + +#endif /* AVCODEC_PSYMODEL_H */ |