ec_gains.h

实现3GPP的GSM中AMR语音的CODECS。

/* ------------------------------------------------------------------
 * Copyright (C) 2008 PacketVideo
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 * -------------------------------------------------------------------
 */
/****************************************************************************************
Portions of this file are derived from the following 3GPP standard:

    3GPP TS 26.073
    ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
    Available from http://www.3gpp.org

(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
Permission to distribute, modify and use this file under the standard license
terms listed above has been obtained from the copyright holder.
****************************************************************************************/
/*
------------------------------------------------------------------------------



 Filename: /audio/gsm_amr/c/src/include/ec_gains.h

     Date: 01/28/2002

------------------------------------------------------------------------------
 REVISION HISTORY

 Description:  Replaced "int" and/or "char" with OSCL defined types.

 Description: Moved _cplusplus #ifdef after Include section.

 Description:

------------------------------------------------------------------------------
 INCLUDE DESCRIPTION

      File             : ec_gains.c
      Purpose:         : Error concealment for pitch and codebook gains

------------------------------------------------------------------------------
*/

#ifndef _EC_GAINS_H_
#define _EC_GAINS_H_
#define ec_gains_h "$Id $"

/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "typedef.h"
#include "gc_pred.h"


/*--------------------------------------------------------------------------*/
#ifdef __cplusplus
extern "C"
{
#endif

    /*----------------------------------------------------------------------------
    ; MACROS
    ; [Define module specific macros here]
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; DEFINES
    ; [Include all pre-processor statements here.]
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; EXTERNAL VARIABLES REFERENCES
    ; [Declare variables used in this module but defined elsewhere]
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; SIMPLE TYPEDEF'S
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; ENUMERATED TYPEDEF'S
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; STRUCTURES TYPEDEF'S
    ----------------------------------------------------------------------------*/
    typedef struct
    {
        Word16 pbuf[5];
        Word16 past_gain_pit;
        Word16 prev_gp;
    } ec_gain_pitchState;

    typedef struct
    {
        Word16 gbuf[5];
        Word16 past_gain_code;
        Word16 prev_gc;
    } ec_gain_codeState;

    /*----------------------------------------------------------------------------
    ; GLOBAL FUNCTION DEFINITIONS
    ; [List function prototypes here]
    ----------------------------------------------------------------------------*/

    /*
     *  Function    : ec_gain_code_reset
     *  Purpose     : Resets state memory
     *
     */
    Word16 ec_gain_code_reset(
        ec_gain_codeState *state
    );


    /*
     *  Function    : ec_gain_code
     *  Purpose     : conceal the codebook gain
     *                Call this function only in BFI (instead of normal gain
     *                decoding function)
     */
    void ec_gain_code(
        ec_gain_codeState *st,    /* i/o : State struct                     */
        gc_predState *pred_state, /* i/o : MA predictor state               */
        Word16 state,             /* i   : state of the state machine       */
        Word16 *gain_code,        /* o   : decoded innovation gain          */
        Flag   *pOverflow
    );

    /*
     *  Function    : ec_gain_code_update
     *  Purpose     : update the codebook gain concealment state;
     *                limit gain_code if the previous frame was bad
     *                Call this function always after decoding (or concealing)
     *                the gain
     */
    void ec_gain_code_update(
        ec_gain_codeState *st,    /* i/o : State struct                     */
        Word16 bfi,               /* i   : flag: frame is bad               */
        Word16 prev_bf,           /* i   : flag: previous frame was bad     */
        Word16 *gain_code,        /* i/o : decoded innovation gain          */
        Flag   *pOverflow
    );


    /*
     *  Function:   ec_gain_pitch_reset
     *  Purpose:    Resets state memory
     */
    Word16 ec_gain_pitch_reset(
        ec_gain_pitchState *state
    );

    /*
     *  Function    : ec_gain_pitch_exit
     *  Purpose     : The memory used for state memory is freed
     */
    void ec_gain_pitch_exit(
        ec_gain_pitchState **state
    );

    /*
     *  Function    : ec_gain_pitch
     *  Purpose     : conceal the pitch gain
     *                Call this function only in BFI (instead of normal gain
     *                decoding function)
     */
    void ec_gain_pitch(
        ec_gain_pitchState *st, /* i/o : state variables                   */
        Word16 state,           /* i   : state of the state machine        */
        Word16 *gain_pitch,     /* o   : pitch gain (Q14)                  */
        Flag   *pOverflow
    );

    /*
     *  Function    : ec_gain_pitch_update
     *  Purpose     : update the pitch gain concealment state;
     *                limit gain_pitch if the previous frame was bad
     *                Call this function always after decoding (or concealing)
     *                the gain
     */
    void ec_gain_pitch_update(
        ec_gain_pitchState *st, /* i/o : state variables                   */
        Word16 bfi,             /* i   : flag: frame is bad                */
        Word16 prev_bf,         /* i   : flag: previous frame was bad      */
        Word16 *gain_pitch,     /* i/o : pitch gain                        */
        Flag   *pOverflow
    );


#ifdef __cplusplus
}
#endif

#endif  /* _EC_GAINS_H_ */