libmadplugin.cpp

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

bool LibMadPlugin::close() {
    debugMsg( "LibMadPlugin::close" );

    int result = TRUE;

    mad_synth_finish(&d->synth);
    mad_frame_finish(&d->frame);
    mad_stream_finish(&d->stream);

#if defined(HAVE_MMAP)
    if (d->input.fdm) {
	if (unmap_file(d->input.fdm, d->input.length) == -1) {
	    qDebug("error munmapping file");
	    result = FALSE;
	}
	d->input.fdm  = 0;
	d->input.data = 0;
    }
#endif

    if (d->input.data) {
        free(d->input.data);
	d->input.data = 0;
    }

    if (::close(d->input.fd) == -1) {
        qDebug("error closing file %s", d->input.path);
	result = FALSE;
    }

    d->input.fd = 0;

    return result;
}


/*! \internal */

bool LibMadPlugin::isOpen() {
    debugMsg( "LibMadPlugin::isOpen" );
    return ( d->input.fd != 0 );
}


/*! \internal */

int LibMadPlugin::audioStreams() {
    debugMsg( "LibMadPlugin::audioStreams" );
    return 1;
}


/*! \internal */

int LibMadPlugin::audioChannels( int ) {
    debugMsg( "LibMadPlugin::audioChannels" );
/*
    long t; short t1[5]; audioReadSamples( t1, 2, 1, t, 0 );
    qDebug( "LibMadPlugin::audioChannels: %i", d->frame.header.mode > 0 ? 2 : 1 );
    return d->frame.header.mode > 0 ? 2 : 1;
*/
    return 2;
}


/*! \internal */

int LibMadPlugin::audioFrequency( int ) {
    debugMsg( "LibMadPlugin::audioFrequency" );
#ifdef OLD_MEDIAPLAYER_API
    long t; short t1[5]; audioReadStereoSamples( t1, 1, t, 0 );
#else
    long t; short t1[5]; audioReadSamples( t1, 2, 1, t, 0 );
#endif
//    qDebug( "LibMadPlugin::audioFrequency: %i", d->frame.header.samplerate );
    return d->frame.header.samplerate;
}

/*! \internal */

int LibMadPlugin::audioSamples( int ) {
    debugMsg( "LibMadPlugin::audioSamples" );

    long t; short t1[5]; audioReadSamples( t1, 2, 1, t, 0 );
    mad_header_decode( (struct mad_header *)&d->frame.header, &d->stream );
/*
    qDebug( "LibMadPlugin::audioSamples: %i*%i", d->frame.header.duration.seconds, d->frame.header.samplerate );
    return d->frame.header.duration.seconds * d->frame.header.samplerate;
*/
    if ( d->frame.header.bitrate == 0 )
	return 0;
    int samples = (d->input.fileLength / (d->frame.header.bitrate/8)) * d->frame.header.samplerate;
    qDebug( "LibMadPlugin::audioSamples: %i * %i * 8 / %i", (int)d->input.fileLength, (int)d->frame.header.samplerate, (int)d->frame.header.bitrate );
    qDebug( "LibMadPlugin::audioSamples: %i", samples );
    return samples;
}

/*! \internal \a pos*/

bool LibMadPlugin::audioSetSample( long pos, int ) {
    debugMsg( "LibMadPlugin::audioSetSample" );

    long totalSamples = audioSamples(0);
    if ( totalSamples <= 1 )
	return FALSE;

    // Seek to requested position
    qDebug( "seek pos: %i", (int)((double)pos * d->input.fileLength / totalSamples) );
    ::lseek( d->input.fd, (long)((double)pos * d->input.fileLength / totalSamples), SEEK_SET );
    mad_stream_sync(&d->stream);

    mad_stream_init(&d->stream);
    mad_frame_init(&d->frame);
    mad_synth_init(&d->synth);

    d->buffered = 0;
    d->resync = TRUE;
    return TRUE;
}

/*! \internal */

long LibMadPlugin::audioGetSample( int ) {
    debugMsg( "LibMadPlugin::audioGetSample" );
    return 0;
}


#ifdef OLD_MEDIAPLAYER_API


/*!
    \internal
*/

bool LibMadPlugin::audioReadSamples( short *, int, long, int ) {
    debugMsg( "LibMadPlugin::audioReadSamples" );
    return FALSE;
}

/*! \internal */

bool LibMadPlugin::audioReReadSamples( short *, int, long, int ) {
    debugMsg( "LibMadPlugin::audioReReadSamples" );
    return FALSE;
}


#endif

/*! \internal */

bool LibMadPlugin::read() {
    debugMsg( "LibMadPlugin::read" );
    int len;

      if (d->input.eof)
	return FALSE;

#if defined(HAVE_MMAP)
      if (d->input.fdm) {
	unsigned long skip = 0;

	if (d->stream.next_frame) {
	  struct stat stat;

	  if (fstat(d->input.fd, &stat) == -1)
	    return FALSE;

	  if (stat.st_size + MAD_BUFFER_GUARD <= (signed)d->input.length)
	    return FALSE;

	  // file size changed; update memory map
	  skip = d->stream.next_frame - d->input.data;

	  if (unmap_file(d->input.fdm, d->input.length) == -1) {
	    d->input.fdm  = 0;
	    d->input.data = 0;
	    return FALSE;
	  }

	  d->input.length = stat.st_size;

	  d->input.fdm = map_file(d->input.fd, &d->input.length);
	  if (d->input.fdm == 0) {
	    d->input.data = 0;
	    return FALSE;
	  }

	  d->input.data = (unsigned char *)d->input.fdm;
	}

	mad_stream_buffer(&d->stream, d->input.data + skip, d->input.length - skip);

      } else
#endif
      {
	if (d->stream.next_frame) {
	  if ( d->stream.next_frame > &d->input.data[d->input.length] )
	    d->input.length = 0;
	  else
	    d->input.length = &d->input.data[d->input.length] - d->stream.next_frame;
	  memmove(d->input.data, d->stream.next_frame, d->input.length);
	}

	if ( d->resync ) {
	  d->input.length = 0;
	  d->resync = FALSE;
	}

	do {
	  len = ::read(d->input.fd, d->input.data + d->input.length, MPEG_BUFFER_SIZE - d->input.length);
	}
	while (len == -1 && errno == EINTR);

	if (len == -1) {
	  qDebug("error reading audio");
	  return FALSE;
	}
	else if (len == 0) {
	  d->input.eof = 1;
	}

	mad_stream_buffer(&d->stream, d->input.data, d->input.length += len);
      }

    return TRUE;
}


static inline signed int scale( mad_fixed_t sample )
{
    sample += (1L << (MAD_F_FRACBITS - 16));
    sample = (sample >= MAD_F_ONE) ? MAD_F_ONE - 1 : ( (sample < -MAD_F_ONE) ? -MAD_F_ONE : sample );
    return sample >> (MAD_F_FRACBITS + 1 - 16);
}


inline void audio_pcm( unsigned short *data, unsigned int nsamples, mad_fixed_t *left, mad_fixed_t *right )
{
    if ( right ) {
	while (nsamples--) {
	    *data++ = scale( *left++ );
	    *data++ = scale( *right++ );
	}
    } else {
	while (nsamples--) {
	    signed int mono = scale( *left++ );
	    *data++ = mono;
	    *data++ = mono;
	}
    }
}

/*! \a output \a samples \a samplesMade \internal */

bool LibMadPlugin::decode( short *output, long samples, long& samplesMade ) {
    debugMsg( "LibMadPlugin::decode" );

    static const int maxBuffered = 8000; // 65536;

    samplesMade = 0;

    if ( !isOpen() )
	return FALSE;

    if ( samples > maxBuffered )
	samples = maxBuffered;

    int offset = d->buffered;

    while ( d->buffered < maxBuffered ) {

	while (mad_frame_decode(&d->frame, &d->stream) == -1) {
	    if ( d->stream.error == MAD_ERROR_BUFLEN ) {
		debugMsg( "feed me" ); // No tr
		qDebug( "feed me" );
		return FALSE; // Feed me
	    }
	    if ( d->stream.error == MAD_ERROR_BADCRC ) {
		mad_frame_mute(&d->frame);
		qDebug( "error decoding, bad crc" );
	    }
	}

	mad_synth_frame(&d->synth, &d->frame);
	int decodedSamples = d->synth.pcm.length;
	memcpy( &(d->buffer[0][offset]), d->synth.pcm.samples[0], decodedSamples * sizeof(mad_fixed_t) );
	if ( d->synth.pcm.channels == 2 )
	    memcpy( &(d->buffer[1][offset]), d->synth.pcm.samples[1], decodedSamples * sizeof(mad_fixed_t) );
	offset += decodedSamples;
	d->buffered += decodedSamples;
    }

    if ( samples >= d->buffered )
	samples = d->buffered;

    audio_pcm( (unsigned short*)output, samples, d->buffer[0], (d->synth.pcm.channels == 2) ? d->buffer[1] : 0 );
    samplesMade = samples;
    d->buffered -= samples;
    memmove( d->buffer[0], &(d->buffer[0][samples]), d->buffered * sizeof(mad_fixed_t) );
    if ( d->synth.pcm.channels == 2 )
	memmove( d->buffer[1], &(d->buffer[1][samples]), d->buffered * sizeof(mad_fixed_t) );

    return TRUE;
}


#ifdef OLD_MEDIAPLAYER_API


bool LibMadPlugin::audioReadMonoSamples( short *, long, long&, int ) {
    debugMsg( "LibMadPlugin::audioReadMonoSamples" );
    return FALSE;
}


bool LibMadPlugin::audioReadStereoSamples( short *output, long samples, long& samplesMade, int ) {

#else

/*!
    \internal
*/

bool LibMadPlugin::audioReadSamples( short *output, int /*channels*/, long samples, long& samplesMade, int ) {

#endif

    debugMsg( "LibMadPlugin::audioReadStereoSamples" );

    static bool needInput = TRUE;

    if ( !isOpen() )
	return FALSE;

    if ( samples == 0 )
	return TRUE;

    if ( d->resync || needInput ) {
	if ( d->input.eof ) {
	    samplesMade = samples;
	    memset( output, 0, samples );
	    return FALSE;
	}
	qDebug("getting more input");
	if ( !read() ) {
	    qDebug("failed getting more input");
	    if ( !d->input.eof ) {
		// Perhaps a timeout happened or some error
		// return 0 samples read but keep needInput flag as TRUE
		// so it retrys reading next time
		samplesMade = 0;
		qDebug("ret a - couldn't get more input");
		return TRUE;
	    }
	}
	needInput = FALSE;
    }

    if ( !decode( output, samples, samplesMade ) ) 
	// Need more input to decode
	needInput = TRUE;
    
    return TRUE;
}

/*! \internal */

double LibMadPlugin::getTime() {
    debugMsg( "LibMadPlugin::getTime" );
    return 0.0;
}

// QDOC_SKIP_END