MetadataBlockDataStreamInfopublic class MetadataBlockDataStreamInfo extends Object implements MetadataBlockData| Stream Info
This block has information about the whole stream, like sample rate, number of channels, total number of samples,
etc. It must be present as the first metadata block in the stream. Other metadata blocks may follow, and ones
that the decoder doesn't understand, it will skip.
Format:
Info
<16> The minimum block size (in samples) used in the stream.
<16> The maximum block size (in samples) used in the stream. (Minimum blocksize == maximum blocksize) implies a fixed-blocksize stream.
<24> The minimum frame size (in bytes) used in the stream. May be 0 to imply the value is not known.
<24> The maximum frame size (in bytes) used in the stream. May be 0 to imply the value is not known.
<20> Sample rate in Hz. Though 20 bits are available, the maximum sample rate is limited by the structure of frame headers to 655350Hz. Also,
a value of 0 is invalid.
<3> (number of channels)-1. FLAC supports from 1 to 8 channels
<5> (bits per sample)-1. FLAC supports from 4 to 32 bits per sample. Currently the reference encoder and decoders only support up to 24 bits per sample.
<36> Total samples in stream. 'Samples' means inter-channel sample,
i.e. one second of 44.1Khz audio will have 44100 samples regardless of the number of channels.
A value of zero here means the number of total samples is unknown.
<128> MD5 signature of the unencoded audio data. This allows the decoder to determine if an error exists in the audio data
even when the error does not result in an invalid bitstream.
NOTES
* FLAC specifies a minimum block size of 16 and a maximum block size of 65535, meaning the bit patterns corresponding to the numbers 0-15 in the minimum blocksize and maximum blocksize fields are invalid. |
| Fields Summary |
|---|
| public static final int | STREAM_INFO_DATA_LENGTH | | public static Logger | logger | | private int | minBlockSize | | private int | maxBlockSize | | private int | minFrameSize | | private int | maxFrameSize | | private int | samplingRate | | private int | samplingRatePerChannel | | private int | bitsPerSample | | private int | channelNumber | | private int | totalNumberOfSamples | | private float | songLength | | private boolean | isValid | | private ByteBuffer | rawdata |
| Constructors Summary |
|---|
public MetadataBlockDataStreamInfo(MetadataBlockHeader header, RandomAccessFile raf)
rawdata = ByteBuffer.allocate(header.getDataLength());
int bytesRead = raf.getChannel().read(rawdata);
if (bytesRead < header.getDataLength())
{
throw new IOException("Unable to read required number of databytes read:" + bytesRead + ":required:" + header.getDataLength());
}
rawdata.rewind();
minBlockSize = rawdata.getShort();
maxBlockSize = rawdata.getShort();
minFrameSize = readThreeByteInteger(rawdata.get(), rawdata.get(), rawdata.get());
maxFrameSize = readThreeByteInteger(rawdata.get(), rawdata.get(), rawdata.get());
samplingRate = readSamplingRate(rawdata.get(), rawdata.get(), rawdata.get());
channelNumber = ((u(rawdata.get(12)) & 0x0E) >>> 1) + 1;
samplingRatePerChannel = samplingRate / channelNumber;
bitsPerSample = ((u(rawdata.get(12)) & 0x01) << 4) + ((u(rawdata.get(13)) & 0xF0) >>> 4) + 1;
totalNumberOfSamples = readTotalNumberOfSamples(rawdata.get(13), rawdata.get(14), rawdata.get(15), rawdata.get(16), rawdata.get(17));
songLength = (float) ((double) totalNumberOfSamples / samplingRate);
logger.config(this.toString());
|
| Methods Summary |
|---|
| public byte[] | getBytes()
return rawdata.array();
| | public int | getChannelNumber()
return channelNumber;
| | public java.lang.String | getEncodingType()
return "FLAC " + bitsPerSample + " bits";
| | public int | getLength()
return getBytes().length;
| | public float | getPreciseLength()
return songLength;
| | public int | getSamplingRate()
return samplingRate;
| | public int | getSamplingRatePerChannel()
return samplingRatePerChannel;
| | public int | getSongLength()
return (int) songLength;
| | public boolean | isValid()
return isValid;
| | private int | readSamplingRate(byte b1, byte b2, byte b3)
int rate = (u(b1) << 12) + (u(b2) << 4) + ((u(b3) & 0xF0) >>> 4);
return rate;
| | private int | readThreeByteInteger(byte b1, byte b2, byte b3)
int rate = (u(b1) << 16) + (u(b2) << 8) + (u(b3));
return rate;
| | private int | readTotalNumberOfSamples(byte b1, byte b2, byte b3, byte b4, byte b5)
int nb = u(b5);
nb += u(b4) << 8;
nb += u(b3) << 16;
nb += u(b2) << 24;
nb += (u(b1) & 0x0F) << 32;
return nb;
| | public java.lang.String | toString()
return "MinBlockSize:" + minBlockSize + "MaxBlockSize:" + maxBlockSize + "MinFrameSize:" + minFrameSize + "MaxFrameSize:" + maxFrameSize + "SampleRateTotal:" + samplingRate + "SampleRatePerChannel:" + samplingRatePerChannel + ":Channel number:" + channelNumber + ":Bits per sample: " + bitsPerSample + ":TotalNumberOfSamples: " + totalNumberOfSamples + ":Length: " + songLength;
| | private int | u(int i)
return i & 0xFF;
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