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/* $Id: HBAc3Decoder.cpp,v 1.6 2003/08/24 15:03:41 titer Exp $ */
#include "HBCommon.h"
#include "HBAc3Decoder.h"
#include "HBManager.h"
#include "HBFifo.h"
extern "C" {
#include <a52dec/a52.h>
}
HBAc3Decoder::HBAc3Decoder( HBManager * manager, HBAudioInfo * audioInfo )
: HBThread( "ac3decoder" )
{
fManager = manager;
fAudioInfo = audioInfo;
fAc3Buffer = NULL;
fAc3Frame = NULL;
fPosInAc3Buffer = 0;
}
void HBAc3Decoder::DoWork()
{
/* Init liba52 */
a52_state_t * state = a52_init( 0 );
int inFlags = 0;
int outFlags = A52_STEREO;
float sampleLevel = 32768; /* lame wants samples from
-32768 to 32768 */
/* Max size for a A52 frame is 3840 bytes */
fAc3Frame = new HBBuffer( 3840 );
int frameSize;
HBBuffer * rawBuffer;
sample_t * samples;
/* Main loop */
while( !fDie )
{
fAc3Frame->fSize = 0;
/* Get a frame header (7 bytes) */
if( !( GetBytes( 7 ) ) )
{
continue;
}
/* Get the size of the current frame */
frameSize = a52_syncinfo( fAc3Frame->fData, &inFlags,
&fAudioInfo->fInSampleRate,
&fAudioInfo->fInBitrate );
if( !frameSize )
{
Log( "HBAc3Decoder : a52_syncinfo failed" );
fManager->Error();
break;
}
/* Get the whole frame */
if( !( GetBytes( (uint32_t) frameSize ) ) )
{
continue;
}
/* Feed liba52 */
a52_frame( state, fAc3Frame->fData, &outFlags, &sampleLevel, 0 );
/* 6 blocks per frame, 256 samples per block */
rawBuffer = new HBBuffer( 12 * 256 * sizeof( float ) );
for( int i = 0; i < 6; i++ )
{
/* Decode a block */
a52_block( state );
/* Get a pointer to the raw data */
samples = a52_samples( state );
/* Copy left channel data */
memcpy( (float*) rawBuffer->fData + i * 256,
samples,
256 * sizeof( float ) );
/* Copy right channel data */
memcpy( (float*) rawBuffer->fData + ( 6 + i ) * 256,
samples + 256,
256 * sizeof( float ) );
}
fAudioInfo->fRawFifo->Push( rawBuffer );
}
/* Clean up */
delete fAc3Frame;
}
/* GetBytes() : pops buffers from the AC3 fifo until fAc3Frame
contains <size> bytes */
bool HBAc3Decoder::GetBytes( uint32_t size )
{
while( fAc3Frame->fSize < size )
{
if( !fAc3Buffer )
{
if( !( fAc3Buffer = fAudioInfo->fAc3Fifo->Pop() ) )
{
return false;
}
fPosInAc3Buffer = 0;
}
int willCopy = MIN( size - fAc3Frame->fSize,
fAc3Buffer->fSize - fPosInAc3Buffer );
memcpy( fAc3Frame->fData + fAc3Frame->fSize,
fAc3Buffer->fData + fPosInAc3Buffer,
willCopy );
fAc3Frame->fSize += willCopy;
fPosInAc3Buffer += willCopy;
if( fAc3Buffer->fSize == fPosInAc3Buffer )
{
delete fAc3Buffer;
fAc3Buffer = NULL;
}
}
return true;
}
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