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+/*
+ * 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 */