AudioRecord.java

/*
 * myLib - https://github.com/taktod/myLib
 * Copyright (c) 2014 ttProject. All rights reserved.
 * 
 * Licensed under The MIT license.
 */
package com.ttProject.media.mp4.atom.stsd;

import java.nio.ByteBuffer;

import com.ttProject.util.BufferUtil;
import com.ttProject.media.mp4.IAtomAnalyzer;
import com.ttProject.media.mp4.atom.stsd.data.Esds;
import com.ttProject.nio.channels.IReadChannel;

@SuppressWarnings("unused")
public abstract class AudioRecord extends Record {
	private byte[] unknown1 = new byte[6];
	private short dataReferenceIndex;
	private int unknown2;
	private int unknown3;
	private short channelCount;
	private short sampleSize;
	private short unknown4;
	private short unknown5;
	private int sampleRate;
	private Esds esds;
	public Esds getEsds() {
		return esds;
	}
	public AudioRecord(String name, int position, int size) {
		super(name, position, size);
	}
	@Override
	public void analyze(IReadChannel ch, IAtomAnalyzer analyzer)
			throws Exception {
		ByteBuffer buffer = BufferUtil.safeRead(ch, 28);
		buffer.get(unknown1);
		dataReferenceIndex = buffer.getShort();
		unknown2 = buffer.getInt(); // ここのデータhi wordがinnerVersion lo wordがrevisionLevelという情報もあり。
		// innerVersionが0でない場合は、sampleRate以降にも情報が16バイトある可能性あり。(未確認)
		unknown3 = buffer.getInt();
		channelCount = buffer.getShort();
		sampleSize = buffer.getShort();
		unknown4 = buffer.getShort();
		unknown5 = buffer.getShort();
		sampleRate = buffer.getInt();
		// 以下サブタグ(size:4 tag:4 body:x)
		// esdsの中身を解析するとaacのmediaSequenceHeaderが見えてくる。
		// この部分の読み込みは別プログラムにした方がいいと思う。
		while(ch.position() < (getSize() + getPosition())) {
			int position = ch.position();
			buffer = BufferUtil.safeRead(ch, 8);
			byte[] name = new byte[4];
			int size = buffer.getInt();
			buffer.get(name);
			String tag = (new String(name)).toLowerCase();
			if("esds".equals(tag)) {
				//esdsのタグ
				esds = new Esds(position, size);
				esds.analyze(ch);
			}
			// tagがesdsなら読み込んでおきたいところ。
			ch.position(position + size);
		}
	}
	public int getChannelCount() {
		return channelCount;
	}
	public int getSampleRate() {
		return (sampleRate >> 16 & 0xFFFF);
	}
}