Meta-Server

System Software Lab

Overview

In the Music Virtual Channel system, clients can’t query for a song initiatively

Through the metadata server, we provide the ability to let clients search for songs using metadata– The metadata server stores the lists of songs that

will be broadcasted

Overview

Music Virtual Channel

streaming information

music stream

query

Metadata Server

client

Query

Query– Clients can make a query based on attributes– The metadata describes the streaming music by the

attributes such as genre, composer, song name…, etc.– To handle the queries, the metadata server will make a

search in the stored data. If a match is found in a one or more broadcast lists, it returns the relative metadata (when will the music be broadcasted, and which channel will broadcast the music) to the client

– A failure message is returned if no match was found

Query

play list

Query

play list

play listmusic metadata

Metadata Server

query

result

Streaming Information

Streaming information– A node that wants to broadcast music will send its play list

to the metadata server. It then begin broadcasting after getting a reply from the metadata server

sliding window on the stored list

– To keep the system synchronized, the metadata server records the time of last update for each broadcasting node. The update message will be dropped if it is older then the newest one

this is a very rough synchronization scheme, and we’re working on a better mechanism to keep the system synchronized

Streaming Information

Metadata Server

broadcasting node

play list

reply msg

play list

play list

play list

Streaming Information

music play list

play list

sliding windowplaying

will play

will play

Streaming Information

Stream metadata attributes– streaming root ip– start timestamp

Music metadata attributes– song title– subtitle– genre– composer– lyricist– performer– album– copyright– language– song playing time

This is not the tables of the database May be edited if need

Progress

Works done– The centralized database

A database built on mySQL system A PHP interface to publish and query

Works to do– The sliding window model is still constructing– We are now working on the centralized database, but will d

evelop a decentralized database in the future– The metadata will be represented in XML– An interface based on Java will be developed