Generating Live Audio/Video Data
[Custom DataSource]

JMF Solutions

Problem

How to generate live audio/video data that can be played back using JMF. This can include translating data received through a non-standard protocol to a format that JMF can recognize. For example, you could be receiving data from a hardware device not supported by JMF. Or you could be using a proprietary protocol that receives packetized audio/video data through an ATM network.

Solution

This solution shows you how to create a custom PushBufferDataSource, which is new to JMF2.0. A PushBufferDataSource contains streams of type PushBufferStream. Such a stream typically generates audio/video data that is organized as frames, rather than a continuous stream of bytes. So each Buffer object carries an entire frame of video or a good sized chunk of audio (anywhere between say 25 millisecs to 2 seconds worth). The data can be in a compressed or uncompressed format. The stream needs to advertise the Format of its data through the getFormat method.

The sample code includes two classes - one is a subclass of PushBufferDataSource and the other is an implementation of PushBufferStream. By default the stream generated is a video stream of raw RGB data. You can change the videoData variable in LiveStream.java to false to generate audio data instead.

Requirements

Platform: JDK 1.1.6 or later
JMF API: 2.0 or later
Implementation: AJ, WPP, SPP*
Other software requirements: Swing 1.1

* AJ = All Java, WPP = Windows Performance Pack, SPP = Solaris Performance Pack

Related Classes

  • javax.media.protocol.PushBufferDataSource
  • javax.media.protocol.PushBufferStream
  • javax.media.protocol.BufferTransferHandler
  • javax.media.Buffer
  • javax.media.Format

How to run this sample

  1. Download the source code and compile it :

    2. javac -d . DataSource.java LiveStream.java

  2. Register the package prefix for the new data source using JMFRegistry
    1. Run JMFRegistry
    2. In the Protocol Prefix List section add "jmfsample" and hit Commit.
  3. Run JMStudio.
  4. Select File->Open URL and enter "live:"
  5. You should now see a video screen with a blue band scrolling up.

Source Code

  • DataSource.java
  • LiveStream.java