long start = raf.getFilePointer();
GenericAudioHeader info = new GenericAudioHeader();
logger.fine("Started");
long oldPos;
//Check start of file does it have Ogg pattern
byte[] b = new byte[OggPageHeader.CAPTURE_PATTERN.length];
raf.read(b);
if (!(Arrays.equals(b, OggPageHeader.CAPTURE_PATTERN)))
{
raf.seek(0);
if(AbstractID3v2Tag.isId3Tag(raf))
{
raf.read(b);
if ((Arrays.equals(b, OggPageHeader.CAPTURE_PATTERN)))
{
start=raf.getFilePointer();
}
}
else
{
throw new CannotReadException(ErrorMessage.OGG_HEADER_CANNOT_BE_FOUND.getMsg(new String(b)));
}
}
//Now work backwards from file looking for the last ogg page, it reads the granule position for this last page
//which must be set.
//TODO should do buffering to cut down the number of file reads
raf.seek(start);
double pcmSamplesNumber = -1;
raf.seek(raf.length() - 2);
while (raf.getFilePointer() >= 4)
{
if (raf.read() == OggPageHeader.CAPTURE_PATTERN[3])
{
raf.seek(raf.getFilePointer() - OggPageHeader.FIELD_CAPTURE_PATTERN_LENGTH);
byte[] ogg = new byte[3];
raf.readFully(ogg);
if (ogg[0] == OggPageHeader.CAPTURE_PATTERN[0] && ogg[1] == OggPageHeader.CAPTURE_PATTERN[1] && ogg[2] == OggPageHeader.CAPTURE_PATTERN[2])
{
raf.seek(raf.getFilePointer() - 3);
oldPos = raf.getFilePointer();
raf.seek(raf.getFilePointer() + OggPageHeader.FIELD_PAGE_SEGMENTS_POS);
int pageSegments = raf.readByte() & 0xFF; //Unsigned
raf.seek(oldPos);
b = new byte[OggPageHeader.OGG_PAGE_HEADER_FIXED_LENGTH + pageSegments];
raf.readFully(b);
OggPageHeader pageHeader = new OggPageHeader(b);
raf.seek(0);
pcmSamplesNumber = pageHeader.getAbsoluteGranulePosition();
break;
}
}
raf.seek(raf.getFilePointer() - 2);
}
if (pcmSamplesNumber == -1)
{
//According to spec a value of -1 indicates no packet finished on this page, this should not occur
throw new CannotReadException(ErrorMessage.OGG_VORBIS_NO_SETUP_BLOCK.getMsg());
}
//1st page = Identification Header
OggPageHeader pageHeader = OggPageHeader.read(raf);
byte[] vorbisData = new byte[pageHeader.getPageLength()];
raf.read(vorbisData);
VorbisIdentificationHeader vorbisIdentificationHeader = new VorbisIdentificationHeader(vorbisData);
//Map to generic encodingInfo
info.setPreciseLength((float) (pcmSamplesNumber / vorbisIdentificationHeader.getSamplingRate()));
info.setChannelNumber(vorbisIdentificationHeader.getChannelNumber());
info.setSamplingRate(vorbisIdentificationHeader.getSamplingRate());
info.setEncodingType(vorbisIdentificationHeader.getEncodingType());
info.setExtraEncodingInfos("");
//TODO this calculation should be done within identification header
if (vorbisIdentificationHeader.getNominalBitrate() != 0 && vorbisIdentificationHeader.getMaxBitrate() == vorbisIdentificationHeader.getNominalBitrate() && vorbisIdentificationHeader.getMinBitrate() == vorbisIdentificationHeader.getNominalBitrate())
{
//CBR (in kbps)
info.setBitrate(vorbisIdentificationHeader.getNominalBitrate() / 1000);
info.setVariableBitRate(false);
}
else
if (vorbisIdentificationHeader.getNominalBitrate() != 0 && vorbisIdentificationHeader.getMaxBitrate() == 0 && vorbisIdentificationHeader.getMinBitrate() == 0)
{
//Average vbr (in kpbs)
info.setBitrate(vorbisIdentificationHeader.getNominalBitrate() / 1000);
info.setVariableBitRate(true);
}
else
{
//TODO need to remove comment from raf.getLength()
info.setBitrate(computeBitrate(info.getTrackLength(), raf.length()));
info.setVariableBitRate(true);
}
logger.fine("Finished");
return info;
