soundstreamhead.java

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/*
 * JSwiff is an open source Java API for Macromedia Flash file generation
 * and manipulation
 *
 * Copyright (C) 2004-2008 Ralf Terdic ([e-mail])
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package com.jswiff.swfrecords.tags;

import com.jswiff.io.InputBitStream;
import com.jswiff.io.OutputBitStream;

import java.io.IOException;


/**
 * <p>
 * This tag is used to define the format of streaming sound data (contained in
 * <code>SoundStreamBlock</code> tags). Streaming sounds defined with this tag
 * are always compressed and their sample size is always 16 bit. For more
 * flexibility, use <code>SoundStreamHead2</code>.
 * </p>
 * 
 * <p>
 * Warning: you are responsible for obtaining technology licenses needed for
 * encoding and decoding sound data (see e.g. <a
 * href="http://mp3licensing.com">mp3licensing.com</a> for details on mp3
 * licensing).
 * </p>
 *
 * @see SoundStreamBlock
 * @see SoundStreamHead2
 * @since SWF 1
 */
public final class SoundStreamHead extends Tag {
	/**
	 * ADPCM compressed sound format (simple compression algorithm without
	 * licensing issues).
	 */
	public static final byte FORMAT_ADPCM  = 1;
	/**
	 * mp3 compressed sound format (for high-quality sound encoding) (since SWF
	 * 4).
	 */
	public static final byte FORMAT_MP3    = 2;
	/** 5.5 kHz sampling rate */
	public static final byte RATE_5500_HZ  = 0;
	/** 11 kHz sampling rate */
	public static final byte RATE_11000_HZ = 1;
	/** 22 kHz sampling rate */
	public static final byte RATE_22000_HZ = 2;
	/** 44 kHz sampling rate */
	public static final byte RATE_44000_HZ = 3;
	private byte playbackRate;
	private boolean playbackStereo;
	private byte streamFormat;
	private byte streamRate;
	private boolean streamStereo;
	private int streamSampleCount;
	private short latencySeek;

	/**
	 * <p>
	 * Creates a new SoundStreamHead tag. Supply the encoding format of the
	 * stream (one of the provided <code>FORMAT_...</code> constants), its
	 * sampling rate (use <code>RATE_...</code> constants), and provide the
	 * channel count (mono / stereo) and the average number of samples (for
	 * stereo sound: sample pairs) per SoundStreamBlock.
	 * </p>
	 * 
	 * <p>
	 * The advisory playback parameters (sampling rate and channel count) are
	 * set to be identical to the stream's parameters specified here. Use
	 * <code>setPlayback...()</code> methods for changing these values.
	 * </p>
	 *
	 * @param streamFormat encoding format (mp3 or ADPCM)
	 * @param rate sampling rate
	 * @param stereo if <code>true</code>, sound is stereo, otherwise mono
	 * @param sampleCount average number of samples (stereo: sample pairs) per
	 * 		  block
	 */
	public SoundStreamHead(
		byte streamFormat, byte rate, boolean stereo, int sampleCount) {
		code					   = TagConstants.SOUND_STREAM_HEAD;
		this.streamFormat		   = streamFormat;
		this.streamRate			   = rate;
		this.playbackRate		   = rate;
		this.streamStereo		   = stereo;
		this.playbackStereo		   = stereo;
		this.streamSampleCount     = sampleCount;
	}

	SoundStreamHead() {
		// empty
	}

	/**
	 * Used only with mp3 streaming sounds; sets the number of mp3 samples to
	 * be skipped at the beginning of the sound stream (initial latency). This
	 * value must match the number of mp3 samples to be skipped (i.e. the
	 * SeekSamples value) from the first SoundStreamBlock.
	 *
	 * @param latencySeek initial latency of sound stream
	 */
	public void setLatencySeek(short latencySeek) {
		this.latencySeek = latencySeek;
	}

	/**
	 * Used only with mp3 streaming sounds; returns the number of mp3 samples
	 * to be skipped at the beginning of the sound stream (initial latency).
	 *
	 * @return initial latency of sound stream
	 */
	public short getLatencySeek() {
		return latencySeek;
	}

	/**
	 * Sets the playback sampling rate.
	 *
	 * @param rate advisory playback rate
	 */
	public void setPlaybackRate(byte rate) {
		this.playbackRate = rate;
	}

	/**
	 * Returns the playback sampling rate.
	 *
	 * @return advisory playback rate
	 */
	public byte getPlaybackRate() {
		return playbackRate;
	}

	/**
	 * Sets the number of channels used at playback (mono/stereo).
	 *
	 * @param isStereo <code>true</code> for stereo, <code>false for
	 * 		  mono</code>
	 */
	public void setPlaybackStereo(boolean isStereo) {
		this.playbackStereo = isStereo;
	}

	/**
	 * Checks the number of channels used at playback (mono/stereo).
	 *
	 * @return <code>true</code> for stereo, <code>false</code> for mono
	 */
	public boolean isPlaybackStereo() {
		return playbackStereo;
	}

	/**
	 * Specifies the encoding format of the sound stream (one of the
	 * <code>FORMAT_...</code> constants).
	 *
	 * @param streamFormat sound encoding format
	 */
	public void setStreamFormat(byte streamFormat) {
		this.streamFormat = streamFormat;
	}

	/**
	 * Returns the encoding format of the sound stream (one of the
	 * <code>FORMAT_...</code> constants).
	 *
	 * @return sound encoding format
	 */
	public byte getStreamFormat() {
		return streamFormat;
	}

	/**
	 * Specifies the sampling rate of the sound stream (one of the
	 * <code>RATE_...</code> constants).
	 *
	 * @param streamRate sampling rate
	 */
	public void setStreamRate(byte streamRate) {
		this.streamRate = streamRate;
	}

	/**
	 * Returns the sampling rate of the sound stream (one of the
	 * <code>RATE_...</code> constants).
	 *
	 * @return sampling rate
	 */
	public byte getStreamRate() {
		return streamRate;
	}

	/**
	 * Specifies the average number of samples (for stereo sound: sample pairs)
	 * per SoundStreamBlock.
	 *
	 * @param streamSampleCount average sample count per block
	 */
	public void setStreamSampleCount(int streamSampleCount) {
		this.streamSampleCount = streamSampleCount;
	}

	/**
	 * Returns the average number of samples (for stereo sound: sample pairs)
	 * per SoundStreamBlock.
	 *
	 * @return average sample count per block
	 */
	public int getStreamSampleCount() {
		return streamSampleCount;
	}

	/**
	 * Specifies whether the streaming sound is stereo or not.
	 *
	 * @param streamStereo <code>true</code> if stereo, otherwise
	 * 		  <code>false</code>
	 */
	public void setStreamStereo(boolean streamStereo) {
		this.streamStereo = streamStereo;
	}

	/**
	 * Checks whether the streaming sound is stereo or not.
	 *
	 * @return <code>true</code> if stereo, otherwise <code>false</code>
	 */
	public boolean isStreamStereo() {
		return streamStereo;
	}

	protected void writeData(OutputBitStream outStream)
		throws IOException {
		outStream.writeUnsignedBits(0, 4); // 4 reserved bits
		outStream.writeUnsignedBits(playbackRate, 2);
		outStream.writeUnsignedBits(1, 1); // playback sample size is always 1
		outStream.writeBooleanBit(playbackStereo);
		outStream.writeUnsignedBits(streamFormat, 4);
		outStream.writeUnsignedBits(streamRate, 2);
		outStream.writeUnsignedBits(1, 1); // streaming sample size is always 1
		outStream.writeBooleanBit(streamStereo);
		outStream.writeUI16(streamSampleCount);
		if (streamFormat == FORMAT_MP3) {
			outStream.writeSI16(latencySeek);
		}
	}

	void setData(byte[] data) throws IOException {
		InputBitStream inStream = new InputBitStream(data);
		inStream.readUnsignedBits(4); // 4 reserved bits
		playbackRate = (byte) inStream.readUnsignedBits(2);
		inStream.readUnsignedBits(1); // playback sample size is always 1
		playbackStereo     = inStream.readBooleanBit();
		streamFormat	   = (byte) inStream.readUnsignedBits(4);
		streamRate		   = (byte) inStream.readUnsignedBits(2);
		inStream.readUnsignedBits(1); // streaming sample size is always 1
		streamStereo		  = inStream.readBooleanBit();
		streamSampleCount     = inStream.readUI16();
		if ((streamFormat == FORMAT_MP3) && (data.length > 4)) {
			latencySeek = inStream.readSI16();
		}
	}
}