thrdecode.c

g.726编解码源程序

/*
 *  Copyright 2002 by Texas Instruments Incorporated.
 *  All rights reserved. Property of Texas Instruments Incorporated.
 *  Restricted rights to use, duplicate or disclose this code are
 *  granted through contract.
 *  
 */
/* "@(#) RF3_UART_G726 1.00.00 07-18-02 (swat-c03)" */
/*
 *  ======== thrDecode.c ========
 *
 *  Static and dynamic initialization of thread Decode,
 *  and its runtime procedure
 */
#include <std.h>
#include <pip.h>

#include <utl.h>                /* debug/diagnostics utility functions */

#include "appResources.h"       /* application-wide common info */
#include "appThreads.h"         /* thread-wide common info */
#include "thrDecode.h"          /* definition of thrDecode objects */

/*
 *  Static part of thread initialization
 */

/* 
 *  Initialization of the thread resources structure:
 *  NULL for algorithm handles, addresses of appropriate 
 *  CDB-defined pipe objects for input and output pipes,
 *  NULL for globally visible temporary pointers to pipe frames,
 *  addresses of intermediate buffers for this thread,
 *  and everything else thread-specific.
 */
ThrDecode thrDecode = {
        /* algorithm handle(s) (to be initialized in runtime) */
        NULL,                      /* algG726DEC */
    
        /* input pipe(s) */
        &pipRxUart,                /* pipIn */

        /* output pipe(s) */
        &pipTxCodec,               /* pipOut */

        /* buffer(s) */
        bufAudioproc,              /* bufInterm */
    
        /* everything else private for the thread */
};

/*
 *  Dynamic part of thread initialization
 */

/*
 *  ========= thrDecodeInit ========
 *  Initialization of data structures for the thread(s), called from 
 *  appThreads.c:thrInit() at init time.
 *
 *  Here we create one instance of G726DEC algorithm. Then We create
 *  parameters for algorithm instance by using the default
 *  parameters and modifying fields that are different.
 */
Void thrDecodeInit( Void ) 
{
    /* declaration of g726 decoder parameter structures */
    G726DEC_Params g726decParams;

    /* 
     *  Set the parameters structure to the default, i.e. 
     *  the one used in i<alg>.c, and modify fields that are different.
     */
    g726decParams = G726DEC_PARAMS;        /* default parameters */
    g726decParams.frameLen  = FRAMELEN;    /* size in samples */
    g726decParams.mode = IG726_LINEAR;     /* linear mode */

    /* create instance, confirm creation success, show memory usage */
    thrDecode.algG726DEC = G726DEC_create( &G726DEC_IG726DEC, &g726decParams );
    UTL_assert( thrDecode.algG726DEC != NULL );
    UTL_showAlgMem( thrDecode.algG726DEC );
}    

/*
 *  Runtime thread code, invoked by the appropriate SWI object
 *  every time the object is posted
 */

Void thrDecodeRun() 
{
    Sample *src, *dst;
    Int     size, i;       /* in samples */

    /*
     *  Check if the codec output pipe is completly empty, if so, allocate
     *  one buffer of silence to the codec to prime the codec output.
     */
    if (PIP_getWriterNumFrames(thrDecode.pipOut) == 2) {
        PIP_alloc ( thrDecode.pipOut );
        memset(PIP_getWriterAddr (thrDecode.pipOut),
                 0 ,PIP_getWriterSize (thrDecode.pipOut));
        PIP_put ( thrDecode.pipOut );
    }

    /*
     *  Check that the preconditions are met, that is the in-pipe 
     *  has a ready-to-consume buffer of data and the out-pipe 
     *  has a free buffer, in other words that this thread has
     *  not been posted in error.
     */
    UTL_assert( PIP_getReaderNumFrames( thrDecode.pipIn  ) > 0 );
    UTL_assert( PIP_getWriterNumFrames( thrDecode.pipOut ) > 0 );

    /* get the full buffer from the input pipe */
    PIP_get( thrDecode.pipIn );
    src = PIP_getReaderAddr( thrDecode.pipIn );
    /* get the size in samples (the function below returns it in words) */
    size = sizeInSamples( PIP_getReaderSize( thrDecode.pipIn ) );

    /* get the empty buffer from the out-pipe */
    PIP_alloc( thrDecode.pipOut );
    dst = PIP_getWriterAddr( thrDecode.pipOut );

    /* unpack received buffer to an intermediate buffer before processing it */
    for (i = 0; i < size * 4; i = i + 4) {
        thrDecode.bufInterm[i]   =  *src       & 0x03;
        thrDecode.bufInterm[i+1] = (*src >> 2) & 0x03;
        thrDecode.bufInterm[i+2] = (*src >> 4) & 0x03;
        thrDecode.bufInterm[i+3] = (*src >> 6) & 0x03;
        src++;
    }

    /* apply G726 decoder algorithm on the intermediate buffer */
   G726DEC_apply(thrDecode.algG726DEC,
               (XDAS_Int8 *)thrDecode.bufInterm, (XDAS_Int16 *)dst );
    
    /* Record the amount of actual data being sent */
    PIP_setWriterSize( thrDecode.pipOut, sizeInWords( size * 4 ) );

    /* Free the receive buffer, put the transmit buffer */
    PIP_free( thrDecode.pipIn  );
    PIP_put ( thrDecode.pipOut );
}