Sets the play gain for the duration of the active play operation.

DWORD adiModifyPlayGain( CTAHD ctahd,
int gain )

ctahd Context handle returned by adiOpenPort.

gain The gain (dB) applied to the data as it is playing (the valid range is -54 to +24).

• SUCCESS
• CTAERR_FUNCTION_NOT_ACTIVE
  Play operation is not currently active.
• CTAERR_INVALID_CTAHD
• CTAERR_INVALID_STATE

None.

This function alters the gain applied to voice data as it is being output. The gain remains set only for the current play operation instance. Values specified out of range will be limited by the range.

adiStartPlaying, adiPlayFromMemory, adiPlayAsync, adiModifyPlaySpeed, adiStopPlaying

int myPlaySmartly( CTAHD ctahd, unsigned encoding,
                   void *buffer, unsigned bufsize )
{
    ADI_PLAY_PARMS playparms;
    ADI_EVENT      event;
    int currentgain = 0;
    int currentspeed = 100;

    adiGetParms( ADI_COLLECT_PARMID, &playparms, sizeof playparms );
    playparms.DTMFabort = 0x0;          /* Don't abort on any DTMF */

    if( adiPlayFromMemory( ctahd, encoding,
                           buffer, bufsize, &playparms ) != SUCCESS )
        return MYFAILURE;

    do 
    {
        myGetEvent( &event );           /* see adiFetchAndProcess example */

        switch( event.id )
        {
            case ADIEVN_DIGIT_BEGIN:
                switch( (char)event.value )
                {
                      case '1':    /* slower */
                          currentspeed -= 20;
                          adiModifyPlaySpeed( ctahd, currentspeed );
                          break;

                      case '3':    /* faster */
                          currentspeed += 20;
                          adiModifyPlaySpeed( ctahd, currentspeed );
                          break;

                      case '4':    /* softer */
                          currentgain -= 3;     /* decrement 3 dB */
                          adiModifyPlayGain( ctahd, currentgain );
                          break;

                      case '6':    /* louder */
                          currentgain += 3;     /* increment 3 dB */
                          adiModifyPlayGain( ctahd, currentgain );
                          break;

                      default:     /* ignore others */
                          break;
            }
                break;

            case ADIEVN_DIGIT_END:          /* ignore end of dtmf */
            case 0:                         /* no event */
            default:
                break;
        }
    } while( event.id != ADIEVN_PLAY_DONE );

    if( event.value != CTA_REASON_FINISHED )
        return MYFAILURE;

    return SUCCESS;
}