|
|
Transmitting Video over RTP
|
|
Problem
How to transmit video over the network using JMF and JMF-RTP. You may
want to transmit video from one computer to another. Or you may want to
broadcast a live video feed to your company's intranet. The source of the
video can be a file, live video using a video capture device or any
other source supported by JMF.
Solution
The VideoTransmit class is a simple wrapper that can be programmed
to take video input from a source of your choice and transmit the video
to a destination computer or network in JPEG format.
The JMF API is used to read the source and convert it to packetized
JPEG data. The RTP API implementation included in JMF will then transmit
the video using the RTP protocol.
The VideoTransmit class takes three parameters in the constructor -
the source locator, the destination IP address and the destination port
number.
The source locator can be -
-
a file name such as "file:/C:/media/speech.mov",
-
an http locator such as "http://mediacentral.com/speech.avi",
-
or a capture datasource such as "vfw://0" or "sunvideo://0/1/JPEG"
vfw: is used on Windows and sunvideo: is used on
Solaris. If you have a more recent PCI based Sun Workstation, then use
sunvideoplus:.
When using vfw, it will pop-up a format dialog when creating the processor.
You should select the size of the video that you would like to transmit
at.
The IP address should be the IP address of the computer that should
receive your transmission. If you want all the computers on your subnet
to receive the transmission, then use 255 as the last number in your IP
address. For example, "129.130.131.132" can be used for a point to point
transmission and "129.130.131.255" can be used for all computers that are
on your subnet. Consult your system administrator if you're not sure what
these IP addresses mean. You can also refer to the JMF RTP documentation
in the JMF Programmer's Guide for more information on RTP transmission
and reception.
The Port number can be any port number that is not in use by
any other service on your computer. For example, you can use "22222". Make
sure that it is an even number. Once again, refer to the Programmer's Guide.
The sample program can be used as a utility class as well as standalone.
There is a main method that takes three command line parameters. If all
goes well, the video will be sent out for 30 seconds and then the application
will exit. This 30 second limit is because there is no GUI that allows
you to specify when to stop the transmission. When doing live video capture
it is very important to properly terminate the capture and release the
device by calling stop and close on the capturing processor.
Note: The source video, whether its a file or live video, needs
to be in a format that can be converted to JPEG/RTP. Cinepak, RGB, YUV
and JPEG are good formats. Other formats may not work due to restrictions
inside the processor. Also the dimensions of the video should be a multiple
of 8x8. For example, 320x240, 176x144 are good sizes and 240x180, 90x60
are not. Experiment with different formats to see what works best for you.
|
|
| Requirements |
|
| Platform: |
JDK 1.1.6 or later |
| JMF API: |
2.0 or later |
| Implementation: |
AJ, WPP, SPP * |
| Hardware: [optional] |
Video Capture card required for live capture. |
* AJ = All Java, WPP = Windows Performance Pack, SPP =
Solaris Performance Pack |
|
|
| Related Classes |
|
|
|
|
| How to run this sample |
|
-
Download and compile the source file.
-
Run VideoTransmit with the required 3 command line parameters
For example,
java VideoTransmit vfw://0 129.144.251.182 42050
-
Or write your own little program that uses the VideoTransmit class to create,
start and stop an RTP transmit session.
-
To receive the transmission on the client side, run JMStudio as
follows:
java JMStudio rtp://<sourceIP>:<port>/video
Where <sourceIP> is the IP address of the transmitting computer
and the port number is the same one that is used on the transmitting side.
|
|
| Source Code |
|
|
|
|
| See Also |
|
-
JMF 2.0 Programmer's Guide
|
|
Print-friendly Version
