org.chenliang.oggus.opus.IdHeader Maven / Gradle / Ivy

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package org.chenliang.oggus.opus;

import com.google.common.io.LittleEndianDataInputStream;
import com.google.common.io.LittleEndianDataOutputStream;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Arrays;

import static java.lang.String.format;

/**
 * The Identification Header packet of a Ogg Opus stream. It has following structure:
 *
 *  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |      'O'      |      'p'      |      'u'      |      's'      |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |      'H'      |      'e'      |      'a'      |      'd'      |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |  Version = 1  | Channel Count |           Pre-skip            |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                     Input Sample Rate (Hz)                    |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |   Output Gain (Q7.8 in dB)    | Mapping Family|               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               :
 * |                                                               |
 * :               Optional Channel Mapping Table...               :
 * |                                                               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * 
 */
public class IdHeader {
    public static final byte[] MAGIC_SIGNATURE = {'O', 'p', 'u', 's', 'H', 'e', 'a', 'd'};
    private int majorVersion;
    private int minorVersion;
    private int channelCount;
    private int preSkip;
    private double outputGain;
    private int coupledCount;
    private long inputSampleRate;
    private int channelMappingFamily;
    private int streamCount;
    private int[] channelMapping;

    private IdHeader() {
    }

    /**
     * Parse {@code IdHeader} from binary data, the data must start with 'OpusHead'.
     *
     * @param data the binary data of ID Header
     * @return IdHeader
     */
    public static IdHeader from(byte[] data) {
        IdHeader idHeader = new IdHeader();
        LittleEndianDataInputStream in = new LittleEndianDataInputStream(new ByteArrayInputStream(data));
        try {
            if (!Arrays.equals(in.readNBytes(8), MAGIC_SIGNATURE)) {
                throw new InvalidOpusException("Id Header packet doesn't start with 'OpusHead'");
            }
            byte version = in.readByte();
            idHeader.majorVersion = version >> 4;
            idHeader.minorVersion = version & 0x0F;
            idHeader.channelCount = in.readUnsignedByte();
            if (idHeader.channelCount < 1) {
                throw new InvalidOpusException("Invalid channel count: " + idHeader.channelCount);
            }
            idHeader.preSkip = in.readUnsignedShort();
            idHeader.inputSampleRate = Integer.toUnsignedLong(in.readInt());
            idHeader.outputGain = in.readUnsignedShort() / 256.0;
            idHeader.channelMappingFamily = in.readUnsignedByte();
            if (idHeader.channelMappingFamily == 0) {
                if (idHeader.channelCount > 2) {
                    throw new InvalidOpusException(format("Invalid channel count: %d, for channel mapping family 0",
                            idHeader.channelCount));
                }
                idHeader.streamCount = 1;
                idHeader.coupledCount = idHeader.channelCount - idHeader.streamCount;
                idHeader.channelMapping = idHeader.channelCount == 1 ? new int[]{0} : new int[]{0, 1};
            } else {
                if (idHeader.channelMappingFamily == 1 && idHeader.channelCount > 8) {
                    throw new InvalidOpusException(format("Invalid channel count: %d, for channel mapping family 1",
                            idHeader.channelCount));
                }
                idHeader.streamCount = in.readUnsignedByte();
                idHeader.coupledCount = in.readUnsignedByte();
                idHeader.channelMapping = new int[idHeader.channelCount];
                for (int i = 0; i < idHeader.channelCount; i++) {
                    idHeader.channelMapping[i] = in.readUnsignedByte();
                }
            }
            return idHeader;
        } catch (IOException e) {
            throw new InvalidOpusException("Id Header data is corrupted");
        }
    }

    /**
     * Create an empty Id Header.
     *
     * @return IdHeader
     */
    public static IdHeader emptyHeader() {
        return new IdHeader();
    }

    /**
     * Dump this IdHeader to binary.
     *
     * @return the binary bytes representation of this IdHeader
     */
    public byte[] dump() {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        LittleEndianDataOutputStream out = new LittleEndianDataOutputStream(byteArrayOutputStream);

        try {
            out.write(MAGIC_SIGNATURE);
            out.writeByte(majorVersion << 4 | minorVersion);
            out.writeByte(channelCount);
            out.writeShort(preSkip);
            out.writeInt((int) inputSampleRate);
            out.writeShort((int) (outputGain * 256));
            out.writeByte(channelMappingFamily);

            if (channelMappingFamily > 0) {
                out.writeByte(streamCount);
                out.writeByte(coupledCount);
                for (int i = 0; i < channelCount; i++) {
                    out.writeByte(channelMapping[i]);
                }
            }
        } catch (IOException e) {
            throw new RuntimeException("IdHeader dump to byte array error", e);
        }

        return byteArrayOutputStream.toByteArray();
    }

    public int getMajorVersion() {
        return majorVersion;
    }

    public void setMajorVersion(int majorVersion) {
        this.majorVersion = majorVersion;
    }

    public int getMinorVersion() {
        return minorVersion;
    }

    public void setMinorVersion(int minorVersion) {
        this.minorVersion = minorVersion;
    }

    public int getChannelCount() {
        return channelCount;
    }

    public void setChannelCount(int channelCount) {
        this.channelCount = channelCount;
    }

    public int getPreSkip() {
        return preSkip;
    }

    public void setPreSkip(int preSkip) {
        this.preSkip = preSkip;
    }

    public double getOutputGain() {
        return outputGain;
    }

    public void setOutputGain(double outputGain) {
        this.outputGain = outputGain;
    }

    public int getCoupledCount() {
        return coupledCount;
    }

    public void setCoupledCount(int coupledCount) {
        this.coupledCount = coupledCount;
    }

    public long getInputSampleRate() {
        return inputSampleRate;
    }

    public void setInputSampleRate(long inputSampleRate) {
        this.inputSampleRate = inputSampleRate;
    }

    public int getChannelMappingFamily() {
        return channelMappingFamily;
    }

    public void setChannelMappingFamily(int channelMappingFamily) {
        this.channelMappingFamily = channelMappingFamily;
    }

    public int getStreamCount() {
        return streamCount;
    }

    public void setStreamCount(int streamCount) {
        this.streamCount = streamCount;
    }

    public int[] getChannelMapping() {
        return channelMapping;
    }

    public void setChannelMapping(int[] channelMapping) {
        this.channelMapping = channelMapping;
    }
}