de.quippy.javamod.multimedia.mp3.streaming

Class IcyInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

java.io.BufferedInputStream

de.quippy.javamod.multimedia.mp3.streaming.IcyInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class IcyInputStream
extends BufferedInputStream

An BufferedInputStream that parses Shoutcast's "icy" metadata from the stream. Gets headers at the beginning and if the "icy-metaint" tag is found, it parses and strips in-stream metadata.

The deal with metaint: Icy streams don't try to put tags between MP3 frames the way that ID3 does. Instead, it requires the client to strip metadata from the stream before it hits the decoder. You get an icy-metaint name/val in the beginning of the stream iff you sent "Icy-Metadata" with value "1" in the request headers (SimpleMP3DataSource does this if the "parseStreamMetadata" boolean is true). If this is the case then the value of icy-metaint is the amount of real data between metadata blocks. Each block begins with an int indicating how much metadata there is -- the block is this value times 16 (it can be, and often is, 0).

Originally thought that "icy" implied Icecast, but this is completely wrong -- real Icecast servers, found through www.icecast.net and typified by URLs with a trailing directory (like CalArts School of Music - http://65.165.174.100:8000/som) do not have the "ICY 200 OK" magic string or any of the CRLF-separated headers. Apparently, "icy" means "Shoutcast". Yep, that's weird.

Author:

Chris Adamson, invalidname@mac.com

Field Summary

Fields

Modifier and Type	Field and Description
protected int	bytesUntilNextMetadata how many bytes of real data remain before the next block of metadata.
protected byte[]	crlfBuffer Buffer for readCRLF line... note this limits lines to 1024 chars (I've read that WinAmp barfs at 128, so this is generous)
protected static String	INLINE_TAG_SEPARATORS inline tags are delimited by ';', also filter out null bytes
protected int	metaint value of the "metaint" tag, which tells us how many bytes of real data are between the metadata tags.

Fields inherited from class java.io.BufferedInputStream

buf, count, marklimit, markpos, pos

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
IcyInputStream(InputStream in) Reads the initial headers of the stream and adds tags appropriatly.
IcyInputStream(InputStream in, String metaIntString, TagParseListener listener) IcyInputStream constructor for know meta-interval (Icecast 2)
IcyInputStream(InputStream in, TagParseListener listener) Reads the initial headers of the stream and adds tags appropriatly.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	addTag(IcyTag tag) adds the tag to the HashMap of tags we have encountered either in-stream or as headers, replacing any previous tag with this name.
void	addTagParseListener(TagParseListener tpl) Adds a TagParseListener to be notified when a stream parses MP3Tags.
void	fireTagParsed(Object source, IcyTag tag)
void	fireTagParseEvent(TagParseEvent tpe) Fires the given event to all registered listeners
IcyTag	getTag(String tagName) Get the named tag from the HashMap of headers and in-line tags.
HashMap<String,IcyTag>	getTagHash() Returns a HashMap of all headers and in-stream tags parsed so far.
IcyTag[]	getTags() Get all tags (headers or in-stream) encountered thus far.
protected void	parseInlineIcyTags(byte[] tagBlock) Parse metadata from an in-stream "block" of bytes, add a tag for each one.
int	read() Reads and returns a single byte.
int	read(byte[] buf) trivial return read (buf, 0, buf.length)
int	read(byte[] buf, int offset, int length) Reads a block of bytes.
protected String	readCRLFLine() Read everything up to the next CRLF, return it as a String.
protected void	readInitialHeaders() Assuming we're at the top of the stream, read lines one by one until we hit a completely blank \r\n.
protected void	readMetadata() Read the next segment of metadata.
void	removeTagParseListener(TagParseListener tpl) Removes a TagParseListener, so it won't be notified when a stream parses MP3Tags.

Methods inherited from class java.io.BufferedInputStream

available, close, mark, markSupported, reset, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INLINE_TAG_SEPARATORS

protected static final String INLINE_TAG_SEPARATORS

inline tags are delimited by ';', also filter out null bytes

See Also:

Constant Field Values

crlfBuffer

protected byte[] crlfBuffer

Buffer for readCRLF line... note this limits lines to 1024 chars (I've read that WinAmp barfs at 128, so this is generous)

metaint

protected int metaint

value of the "metaint" tag, which tells us how many bytes of real data are between the metadata tags. if -1, this stream does not have metadata after the header.

bytesUntilNextMetadata

protected int bytesUntilNextMetadata

how many bytes of real data remain before the next block of metadata. Only meaningful if metaint != -1.

Constructor Detail

IcyInputStream

public IcyInputStream(InputStream in,
              String metaIntString,
              TagParseListener listener)
               throws IOException

IcyInputStream constructor for know meta-interval (Icecast 2)

Parameters:

in -

metaint -

Throws:

IOException

IcyInputStream

public IcyInputStream(InputStream in)
               throws IOException

Reads the initial headers of the stream and adds tags appropriatly. Gets set up to find, read, and strip blocks of in-line metadata if the icy-metaint header is found.

Throws:

IOException

IcyInputStream

public IcyInputStream(InputStream in,
              TagParseListener listener)
               throws IOException

Reads the initial headers of the stream and adds tags appropriatly. Gets set up to find, read, and strip blocks of in-line metadata if the icy-metaint header is found.

Throws:

IOException

Method Detail

readInitialHeaders

protected void readInitialHeaders()
                           throws IOException

Assuming we're at the top of the stream, read lines one by one until we hit a completely blank \r\n. Parse the data as IcyTags.

Throws:

IOException

readCRLFLine

protected String readCRLFLine()
                       throws IOException

Read everything up to the next CRLF, return it as a String.

Throws:

IOException

read

public int read()
         throws IOException

Reads and returns a single byte. If the next byte is a metadata block, then that block is read, stripped, and parsed before reading and returning the first byte after the metadata block.

Overrides:

read in class BufferedInputStream

Throws:

IOException

read

public int read(byte[] buf,
       int offset,
       int length)
         throws IOException

Reads a block of bytes. If the next byte is known to be a block of metadata, then that is read, parsed, and stripped, and then a block of bytes is read and returned. Otherwise, it may read up to but not into the next metadata block if bytesUntilNextMetadata < length

Overrides:

read in class BufferedInputStream

Throws:

IOException

read

public int read(byte[] buf)
         throws IOException

trivial return read (buf, 0, buf.length)

Overrides:

read in class FilterInputStream

Throws:

IOException

readMetadata

protected void readMetadata()
                     throws IOException

Read the next segment of metadata. The stream must be right on the segment, ie, the next byte to read is the metadata block count. The metadata is parsed and new tags are added with addTag(), which fires events

Throws:

IOException

parseInlineIcyTags

protected void parseInlineIcyTags(byte[] tagBlock)

Parse metadata from an in-stream "block" of bytes, add a tag for each one.

Hilariously, the inline data format is totally different than the top-of-stream header. For example, here's a block I saw on "Final Fantasy Radio":

        StreamTitle='Final Fantasy 8 - Nobuo Uematsu - Blue Fields';StreamUrl='';
        

In other words:

1. Tags are delimited by semicolons
2. Keys/values are delimited by equals-signs
3. Values are wrapped in single-quotes
4. Key names are in SentenceCase, not lowercase-dashed

addTag

protected void addTag(IcyTag tag)

adds the tag to the HashMap of tags we have encountered either in-stream or as headers, replacing any previous tag with this name.

getTag

public IcyTag getTag(String tagName)

Get the named tag from the HashMap of headers and in-line tags. Null if no such tag has been encountered.

getTags

public IcyTag[] getTags()

Get all tags (headers or in-stream) encountered thus far.

getTagHash

public HashMap<String,IcyTag> getTagHash()

Returns a HashMap of all headers and in-stream tags parsed so far.

addTagParseListener

public void addTagParseListener(TagParseListener tpl)

Adds a TagParseListener to be notified when a stream parses MP3Tags.

removeTagParseListener

public void removeTagParseListener(TagParseListener tpl)

Removes a TagParseListener, so it won't be notified when a stream parses MP3Tags.

fireTagParseEvent

public void fireTagParseEvent(TagParseEvent tpe)

Fires the given event to all registered listeners

fireTagParsed

public void fireTagParsed(Object source,
                 IcyTag tag)