sdl_umsaudio.c

jpeg and mpeg 编解码技术源代码

            rc = UADSetByteOrder(this, "MSB");       /* irrelevant */
            rc = UADSetNumberFormat(this, "SIGNED");
            break;
        case AUDIO_S16LSB:
	    success       = 1;
            bitsPerSample = 16;
            rc = UADSetSampleRate(this,  spec->freq << 16, &outRate );
            rc = UADSetByteOrder(this, "LSB");
            rc = UADSetNumberFormat(this, "SIGNED");
            break;
        case AUDIO_S16MSB:
	    success       = 1;
            bitsPerSample = 16;
            rc = UADSetSampleRate(this,  spec->freq << 16, &outRate );
            rc = UADSetByteOrder(this, "MSB");
            rc = UADSetNumberFormat(this, "SIGNED");
            break;
        case AUDIO_U16LSB:
	    success       = 1;
            bitsPerSample = 16;
            rc = UADSetSampleRate(this,  spec->freq << 16, &outRate );
            rc = UADSetByteOrder(this, "LSB");
            rc = UADSetNumberFormat(this, "UNSIGNED");
            break;
        case AUDIO_U16MSB:
	    success       = 1;
            bitsPerSample = 16;
            rc = UADSetSampleRate(this,  spec->freq << 16, &outRate );
            rc = UADSetByteOrder(this, "MSB");
            rc = UADSetNumberFormat(this, "UNSIGNED");
            break;
        default:
            break;
        }
        if ( ! success ) {
            test_format = SDL_NextAudioFormat();
        }
    }
    while ( ! success && test_format );

    if ( success == 0 ) {
        SDL_SetError("Couldn't find any hardware audio formats");
        return -1;
    }

    spec->format = test_format;

    for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec );
    if ( (0x01<<frag_spec) != spec->size ) {
        SDL_SetError("Fragment size must be a power of two");
        return -1;
    }
    if ( frag_spec > 2048 ) frag_spec = 2048;

    this->hidden->bytesPerSample   = (bitsPerSample / 8) * spec->channels;
    samplesPerSec                  = this->hidden->bytesPerSample * outRate;

    this->hidden->playbuf._length  = 0;
    this->hidden->playbuf._maximum = spec->size;
    this->hidden->playbuf._buffer  = (unsigned char*)malloc(spec->size);
    this->hidden->fillbuf._length  = 0;
    this->hidden->fillbuf._maximum = spec->size;
    this->hidden->fillbuf._buffer  = (unsigned char*)malloc(spec->size);

    rc = UADSetBitsPerSample(this,  bitsPerSample );
    rc = UADSetDMABufferSize(this,  frag_spec, &outBufSize );
    rc = UADSetChannels(this, spec->channels);      /* functions reduces to mono or stereo */

    lgain = 100; /*maximum left input gain*/
    rgain = 100; /*maimum right input gain*/
    rc = UADEnableOutput(this, "LINE_OUT",&lgain,&rgain);
    rc = UADInitialize(this);
    rc = UADStart(this);
    rc = UADSetVolume(this, 100);
    rc = UADSetBalance(this, 0);

    /* We're ready to rock and roll. :-) */
    return 0;
}


static UMSAudioDevice_ReturnCode UADGetBitsPerSample(_THIS, long* bits)
{
    return UMSAudioDevice_get_bits_per_sample( this->hidden->umsdev,
					       this->hidden->ev,
					       bits );
}

static UMSAudioDevice_ReturnCode UADSetBitsPerSample(_THIS, long bits)
{
    return UMSAudioDevice_set_bits_per_sample( this->hidden->umsdev,
					       this->hidden->ev,
					       bits );
}

static UMSAudioDevice_ReturnCode UADSetSampleRate(_THIS, long rate, long* set_rate)
{
    /* from the mac code: sample rate = spec->freq << 16; */
    return UMSAudioDevice_set_sample_rate( this->hidden->umsdev,
					   this->hidden->ev,
					   rate,
					   set_rate );
}

static UMSAudioDevice_ReturnCode UADSetByteOrder(_THIS, string byte_order)
{
    return UMSAudioDevice_set_byte_order( this->hidden->umsdev,
					  this->hidden->ev,
					  byte_order );
}

static UMSAudioDevice_ReturnCode UADSetAudioFormatType(_THIS, string fmt)
{
    /* possible PCM, A_LAW or MU_LAW */
    return UMSAudioDevice_set_audio_format_type( this->hidden->umsdev,
						 this->hidden->ev,
						 fmt );
}

static UMSAudioDevice_ReturnCode UADSetNumberFormat(_THIS, string fmt)
{
    /* possible SIGNED, UNSIGNED, or TWOS_COMPLEMENT */
    return UMSAudioDevice_set_number_format( this->hidden->umsdev,
					     this->hidden->ev,
					     fmt );
}

static UMSAudioDevice_ReturnCode UADInitialize(_THIS)
{
    return UMSAudioDevice_initialize( this->hidden->umsdev,
				      this->hidden->ev );
}

static UMSAudioDevice_ReturnCode UADStart(_THIS)
{
    return UMSAudioDevice_start( this->hidden->umsdev,
				 this->hidden->ev );
}

static UMSAudioDevice_ReturnCode UADSetTimeFormat(_THIS,  UMSAudioTypes_TimeFormat fmt )
{
    /*
     * Switches the time format to the new format, immediately.
     * possible UMSAudioTypes_Msecs, UMSAudioTypes_Bytes or UMSAudioTypes_Samples
     */
    return UMSAudioDevice_set_time_format( this->hidden->umsdev,
					   this->hidden->ev,
					   fmt );
}

static UMSAudioDevice_ReturnCode UADWriteBuffSize(_THIS,  long* buff_size )
{
    /*
     * returns write buffer size in the current time format
     */
    return UMSAudioDevice_write_buff_size( this->hidden->umsdev,
                                           this->hidden->ev,
					   buff_size );
}

static UMSAudioDevice_ReturnCode UADWriteBuffRemain(_THIS,  long* buff_size )
{
    /*
     * returns amount of available space in the write buffer
     * in the current time format
     */
    return UMSAudioDevice_write_buff_remain( this->hidden->umsdev,
                                             this->hidden->ev,
					     buff_size );
}

static UMSAudioDevice_ReturnCode UADWriteBuffUsed(_THIS,  long* buff_size )
{
    /*
     * returns amount of filled space in the write buffer
     * in the current time format
     */
    return UMSAudioDevice_write_buff_used( this->hidden->umsdev,
                                           this->hidden->ev,
					   buff_size );
}

static UMSAudioDevice_ReturnCode UADSetDMABufferSize(_THIS,  long bytes, long* bytes_ret )
{
    /*
     * Request a new DMA buffer size, maximum requested size 2048.
     * Takes effect with next initialize() call.
     * Devices may or may not support DMA.
     */
    return UMSAudioDevice_set_DMA_buffer_size( this->hidden->umsdev,
					       this->hidden->ev,
					       bytes,
					       bytes_ret );
}

static UMSAudioDevice_ReturnCode UADSetVolume(_THIS,  long volume )
{
    /*
     * Set the volume.
     * Takes effect immediately.
     */
    return UMSAudioDevice_set_volume( this->hidden->umsdev,
				      this->hidden->ev,
				      volume );
}

static UMSAudioDevice_ReturnCode UADSetBalance(_THIS,  long balance )
{
    /*
     * Set the balance.
     * Takes effect immediately.
     */
    return UMSAudioDevice_set_balance( this->hidden->umsdev,
				       this->hidden->ev,
				       balance );
}

static UMSAudioDevice_ReturnCode UADSetChannels(_THIS,  long channels )
{
    /*
     * Set mono or stereo.
     * Takes effect with next initialize() call.
     */
    if ( channels != 1 ) channels = 2;
    return UMSAudioDevice_set_number_of_channels( this->hidden->umsdev,
				                  this->hidden->ev,
				                  channels );
}

static UMSAudioDevice_ReturnCode UADOpen(_THIS,  string device, string mode, long flags)
{
    return UMSAudioDevice_open( this->hidden->umsdev,
				this->hidden->ev,
				device,
				mode,
				flags );
}

static UMSAudioDevice_ReturnCode UADWrite(_THIS,  UMSAudioTypes_Buffer* buff,
                                           long samples,
					   long* samples_written)
{
    return UMSAudioDevice_write( this->hidden->umsdev,
				 this->hidden->ev,
				 buff,
				 samples,
				 samples_written );
}

static UMSAudioDevice_ReturnCode UADPlayRemainingData(_THIS,  boolean block )
{
    return UMSAudioDevice_play_remaining_data( this->hidden->umsdev,
					       this->hidden->ev,
					       block);
}

static UMSAudioDevice_ReturnCode UADStop(_THIS)
{
    return UMSAudioDevice_stop( this->hidden->umsdev,
				this->hidden->ev );
}

static UMSAudioDevice_ReturnCode UADClose(_THIS)
{
    return UMSAudioDevice_close( this->hidden->umsdev,
				 this->hidden->ev );
}

static UMSAudioDevice_ReturnCode UADEnableOutput(_THIS,  string output, long* left_gain, long* right_gain)
{
    return UMSAudioDevice_enable_output( this->hidden->umsdev,
					 this->hidden->ev,
					 output,
					 left_gain,
					 right_gain );
}