PANVEGA’s Blog

DotNet Development, SharePoint Customizing, Silverlight, MS Infrastructure and other tips and tricks

Streaming RealMedia Files (RTSP)

Posted by PANVEGA on February 10, 2009

RTP does not operate on assigned or standardized TCP or UDP ports. However, usually it uses even port numbers. RTCP uses the next higher odd port number. Although there are no standardized recommendations, RTP is often configured to use ports 16384-32767, but may be observed frequently outside this range as well.

The streams controlled by RTSP may use RTP, but the operation of RTSP does not depend on the transport mechanism used to carry continuous media. RTSP is intentionally similar in syntax and operation to HTTP/1.1 so that extension mechanisms to HTTP can in most cases also be added to RTSP. However, RTSP differs in a number of important aspects from HTTP:

  • RTSP introduces a number of new methods and has a different protocol identifier.
  • An RTSP server needs to maintain state by default in almost all cases, as opposed to the stateless nature of HTTP.
  • Both an RTSP server and client can issue requests.
  • Data is carried out-of-band by a different protocol, in most cases.
  • RTSP is defined to use ISO 10646 (UTF-8) rather than ISO 8859-1,consistent with current HTML internationalization efforts.
  • The Request-URI always contains the absolute URI. Because of backward compatibility with a historical blunder, HTTP/1.1 carries only the absolute path in the request and puts the host name in a separate header field.

The protocol supports the following operations:

  • Retrieval of media from media server: The client can request a presentation description via HTTP or some other method.
  • Invitation of a media server to a conference: A media server can be “invited” to join an existing conference, either to play back media into the presentation or to record all or a subset of the media in a presentation.
  • Addition of media to an existing presentation: Particularly for live presentations, it is useful if the server can tell the client about additional media becoming available.

Even without access to a RealMedia server, you can still serve RealAudio and RealMedia files. Here’s how:

1. If you alread have your streaming file scip this step. Use the free encoder to create .ra and/or .rm files. Keep them small because the user will have to download them instead of streaming them. With small files this will be transparent.

2. In your HTML Site create a simple Hyperlink. Create a .ram metafile for each Real file that contains a single line stating the complete URL of the corresponding .ra or .rm file.

e.g.  <a href=”example.ram”  target=”_blank”>RTSP File</a>

3. In your example.ram file add the whole URL like this:

http://www.providerxy.com/example.rm

rtsp://realserver.providerxy.com/example.rm

4. If the Enduser has already installed the RealPlayer, it will start automatically. Otherwise add a Linke in your Website, where the user can download the player.

http://www.chip.de/downloads/Real-Alternative_15759882.html

Now you can go to your webpage and click on the hyperlink to playback the RealMedia clip.

5. If you want to bring more functionallity and more control in your stream use the SMIL language.

Follow my other post about SMIL

Clients

More Informations:

http://service.real.com/help/library/guides/realone/ProductionGuide/HTML/htmfiles/linking.htm

http://www.cs.columbia.edu/~hgs/teaching/ais/slides/2003/RTSP.pdf

http://msdn.microsoft.com/en-us/library/cc245238(PROT.10).aspx

http://www.answers.com/topic/rtsp

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One Response to “Streaming RealMedia Files (RTSP)”

  1. […] RTSP is defined to use ISO 10646 (UTF-8) rather than ISO 8859-1,consistent with current HTML internationalization efforts. The Request-URI always contains the absolute URI. Because of backward compatibility with a …Continue Reading […]

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