rockbox/apps/codecs/libspeex/speex/speex_stereo.h

/* Copyright (C) 2002 Jean-Marc Valin*/
/**
   @file speex_stereo.h
   @brief Describes the handling for intensity stereo
*/
/*
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   are met:
   
   - Redistributions of source code must retain the above copyright
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   notice, this list of conditions and the following disclaimer in the
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   - Neither the name of the Xiph.org Foundation nor the names of its
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   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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*/

#ifndef STEREO_H
#define STEREO_H
/** @defgroup SpeexStereoState SpeexStereoState: Handling Speex stereo files
 *  This describes the Speex intensity stereo encoding/decoding
 *  @{
 */

#include "speex_types.h"
#include "speex_bits.h"

#ifdef __cplusplus
extern "C" {
#endif

/** If you access any of these fields directly, I'll personally come and bite you */
typedef struct SpeexStereoState {
   float balance;      /**< Left/right balance info */
   float e_ratio;      /**< Ratio of energies: E(left+right)/[E(left)+E(right)]  */
   float smooth_left;  /**< Smoothed left channel gain */
   float smooth_right; /**< Smoothed right channel gain */
   float reserved1;    /**< Reserved for future use */
   float reserved2;    /**< Reserved for future use */
} SpeexStereoState;

/** Deprecated. Use speex_stereo_state_init() instead. */
#define SPEEX_STEREO_STATE_INIT {1,.5,1,1,0,0}

/** Initialise/create a stereo stereo state */
SpeexStereoState *speex_stereo_state_init();

/** Reset/re-initialise an already allocated stereo state */
void speex_stereo_state_reset(SpeexStereoState *stereo);

/** Destroy a stereo stereo state */
void speex_stereo_state_destroy(SpeexStereoState *stereo);

/** Transforms a stereo frame into a mono frame and stores intensity stereo info in 'bits' */
void speex_encode_stereo(float *data, int frame_size, SpeexBits *bits);

/** Transforms a stereo frame into a mono frame and stores intensity stereo info in 'bits' */
void speex_encode_stereo_int(spx_int16_t *data, int frame_size, SpeexBits *bits);

/** Transforms a mono frame into a stereo frame using intensity stereo info */
void speex_decode_stereo(float *data, int frame_size, SpeexStereoState *stereo);

/** Transforms a mono frame into a stereo frame using intensity stereo info */
void speex_decode_stereo_int(spx_int16_t *data, int frame_size, SpeexStereoState *stereo);

/** Callback handler for intensity stereo info */
int speex_std_stereo_request_handler(SpeexBits *bits, void *state, void *data);

#ifdef __cplusplus
}
#endif

/** @} */
#endif