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/* $Id: Ac3Decoder.cpp,v 1.12 2003/09/30 14:38:15 titer Exp $
This file is part of the HandBrake source code.
Homepage: <http://beos.titer.org/handbrake/>.
It may be used under the terms of the GNU General Public License. */
#include "Ac3Decoder.h"
#include "Fifo.h"
#include "Manager.h"
extern "C" {
#include <a52dec/a52.h>
}
HBAc3Decoder::HBAc3Decoder( HBManager * manager, HBAudio * audio )
: HBThread( "ac3decoder" )
{
fManager = manager;
fAudio = audio;
/* Max size for a A52 frame is 3840 bytes */
fAc3Frame = new HBBuffer( 3840 );
fAc3Buffer = NULL;
fPosInBuffer = 0;
fPosition = 0;
}
HBAc3Decoder::~HBAc3Decoder()
{
delete fAc3Frame;
}
void HBAc3Decoder::DoWork()
{
/* Init liba52 */
a52_state_t * state = a52_init( 0 );
int inFlags = 0;
int outFlags = A52_STEREO;
/* Lame wants samples from -32768 to 32768 */
float sampleLevel = 32768;
int frameSize;
HBBuffer * rawBuffer;
sample_t * samples;
/* Main loop */
for( ;; )
{
while( fSuspend )
{
Snooze( 10000 );
}
fAc3Frame->fSize = 0;
/* Get a frame header (7 bytes) */
if( !( GetBytes( 7 ) ) )
{
break;
}
/* Get the size of the current frame */
frameSize = a52_syncinfo( fAc3Frame->fData, &inFlags,
&fAudio->fInSampleRate,
&fAudio->fInBitrate );
if( !frameSize )
{
Log( "HBAc3Decoder : a52_syncinfo failed" );
fManager->Error();
break;
}
/* Get the whole frame */
if( !( GetBytes( (uint32_t) frameSize ) ) )
{
break;
}
/* 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 ) );
rawBuffer->fPosition = fPosition;
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 ) );
}
if( !Push( fAudio->fRawFifo, rawBuffer ) )
{
break;
}
}
}
/* 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 = Pop( fAudio->fAc3Fifo ) ) )
{
return false;
}
fPosInBuffer = 0;
fPosition = fAc3Buffer->fPosition;
}
int willCopy = MIN( size - fAc3Frame->fSize,
fAc3Buffer->fSize - fPosInBuffer );
memcpy( fAc3Frame->fData + fAc3Frame->fSize,
fAc3Buffer->fData + fPosInBuffer,
willCopy );
fAc3Frame->fSize += willCopy;
fPosInBuffer += willCopy;
if( fAc3Buffer->fSize == fPosInBuffer )
{
delete fAc3Buffer;
fAc3Buffer = NULL;
}
}
return true;
}
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