AC3FrameParams Class Reference


Public Member Functions
	AC3FrameParams ()
void	setParamsFromHeader ()
Data Fields
unsigned	hdr0
unsigned	hdr1
unsigned	kbps
unsigned	samplingFreq
unsigned	frameSize

Detailed Description

Definition at line 27 of file AC3AudioStreamFramer.cpp.

Constructor & Destructor Documentation

AC3FrameParams::AC3FrameParams ( ) [inline]

Definition at line 29 of file AC3AudioStreamFramer.cpp.

00029 : samplingFreq(0) {}

Member Function Documentation

void AC3FrameParams::setParamsFromHeader ( )

Definition at line 193 of file AC3AudioStreamFramer.cpp.

References frameSize, hdr1, kbps, kbpsTable, and samplingFreq.

Referenced by AC3AudioStreamParser::parseFrame().

00193                                          {
00194   unsigned char byte4 = hdr1 >> 24;
00195 
00196   unsigned char kbpsIndex = (byte4&0x3E) >> 1;
00197   if (kbpsIndex > 18) kbpsIndex = 18;
00198   kbps = kbpsTable[kbpsIndex];
00199 
00200   unsigned char samplingFreqIndex = (byte4&0xC0) >> 6;
00201   switch (samplingFreqIndex) {
00202   case 0:
00203     samplingFreq = 48000;
00204     frameSize = 4*kbps;
00205     break;
00206   case 1:
00207     samplingFreq = 44100;
00208     frameSize = 2*(320*kbps/147 + (byte4&1));
00209     break;
00210   case 2:
00211   case 3: // not legal?
00212     samplingFreq = 32000;
00213     frameSize = 6*kbps;
00214   }
00215 }