File	Doc	Category	Size	Date	Package
Mp4EsdsBox.java	API Doc	Jaudiotagger 2.0.4	10838	Wed Mar 30 16:11:44 BST 2011	org.jaudiotagger.audio.mp4.atom

Mp4EsdsBox

• java.lang.Object
  • AbstractMp4Box

Fields Summary
public static final int	VERSION_FLAG_LENGTH
public static final int	OTHER_FLAG_LENGTH
public static final int	DESCRIPTOR_TYPE_LENGTH
public static final int	ES_ID_LENGTH
public static final int	STREAM_PRIORITY_LENGTH
public static final int	CONFIG_TYPE_LENGTH
public static final int	OBJECT_TYPE_LENGTH
public static final int	STREAM_TYPE_LENGTH
public static final int	BUFFER_SIZE_LENGTH
public static final int	MAX_BITRATE_LENGTH
public static final int	AVERAGE_BITRATE_LENGTH
public static final int	DESCRIPTOR_OBJECT_TYPE_LENGTH
public static final int	CHANNEL_FLAGS_LENGTH
private Kind	kind
private AudioProfile	audioProfile
private int	numberOfChannels
private int	maxBitrate
private int	avgBitrate
private static final int	SECTION_THREE
private static final int	SECTION_FOUR
private static final int	SECTION_FIVE
private static final int	SECTION_SIX
private static final int	FILLER_START
private static final int	FILLER_OTHER
private static final int	FILLER_END
private static Map	kindMap
private static Map	audioProfileMap

Constructors Summary

public Mp4EsdsBox(Mp4BoxHeader header, ByteBuffer dataBuffer) DataBuffer must start from from the start of the body param header header info param dataBuffer data of box (doesnt include header data) //Create maps to speed up lookup from raw value to enum kindMap = new HashMap<Integer, Kind>(); for (Kind next : Kind.values()) { kindMap.put(next.getId(), next); } audioProfileMap = new HashMap<Integer, AudioProfile>(); for (AudioProfile next : AudioProfile.values()) { audioProfileMap.put(next.getId(), next); } this.header = header; //Not currently used, as lengths can extend over more than one section i think int sectionThreeLength; int sectionFourLength; int sectionFiveLength; int sectionSixLength; //As explained earlier the length of this atom is not fixed so processing is a bit more difficult //Process Flags dataBuffer.position(dataBuffer.position() + VERSION_FLAG_LENGTH + OTHER_FLAG_LENGTH); //Process Section 3 if exists if (dataBuffer.get() == SECTION_THREE) { sectionThreeLength = processSectionHeader(dataBuffer); //Skip Other Section 3 data dataBuffer.position(dataBuffer.position() + ES_ID_LENGTH + STREAM_PRIORITY_LENGTH); } //Process Section 4 (to getFields type and bitrate) if (dataBuffer.get() == SECTION_FOUR) { sectionFourLength = processSectionHeader(dataBuffer); //kind (in iTunes) kind = kindMap.get((int) dataBuffer.get()); //Skip Other Section 4 data dataBuffer.position(dataBuffer.position() + STREAM_TYPE_LENGTH + BUFFER_SIZE_LENGTH); //Bit rates this.maxBitrate = Utils.getIntBE(dataBuffer, dataBuffer.position(), (dataBuffer.position() + MAX_BITRATE_LENGTH - 1)); dataBuffer.position(dataBuffer.position() + MAX_BITRATE_LENGTH); this.avgBitrate = Utils.getIntBE(dataBuffer, dataBuffer.position(), (dataBuffer.position() + AVERAGE_BITRATE_LENGTH - 1)); dataBuffer.position(dataBuffer.position() + AVERAGE_BITRATE_LENGTH); } //Process Section 5,(to getFields no of channels and audioprofile(profile in itunes)) if (dataBuffer.get() == SECTION_FIVE) { sectionFiveLength = processSectionHeader(dataBuffer); //Audio Profile audioProfile = audioProfileMap.get((dataBuffer.get() >> 3)); //Channels byte channelByte = dataBuffer.get(); numberOfChannels = (channelByte << 1) >> 4; } //Process Section 6, not needed ...

Methods Summary
public org.jaudiotagger.audio.mp4.atom.Mp4EsdsBox$AudioProfile	getAudioProfile() Get audio profile, usually AAC Low Complexity return the audio profile return audioProfile;
public int	getAvgBitrate() return average bit rate (bps) return avgBitrate;
public org.jaudiotagger.audio.mp4.atom.Mp4EsdsBox$Kind	getKind() Only expext MPG_Audio, TODO shouldnt matter if another type of audio, but something gone wrong if type of video return the file type for the track return kind;
public int	getMaxBitrate() return maximum bit rate (bps) return maxBitrate;
public int	getNumberOfChannels() return numberOfChannels;
public int	processSectionHeader(java.nio.ByteBuffer dataBuffer) Process header, skipping filler bytes and calculating size param dataBuffer return section header int datalength; byte nextByte = dataBuffer.get(); if (((nextByte & 0xFF) == FILLER_START) || ((nextByte & 0xFF) == FILLER_OTHER) || ((nextByte & 0xFF) == FILLER_END)) { dataBuffer.get(); dataBuffer.get(); datalength = dataBuffer.get(); } else { datalength = nextByte; } return datalength;