RealAudio Starting Tips
Before setting up a .ram metafile, let me first clarify the concept of a BaseDirectory. On "jan" the "BaseDirectory" is /home so that any references to RealAudio files are relative to the /home directory on jan. All .ra files must be located in or below the user's home directory (for example, /home/tjk). To provide ready access to these files via the Web, it would probably be best to put .ra files in or below one's public_html subdirectory. Here is an example of how to set up a proper link to a RealAudio file so that it will stream through the server:
If I have a RealAudio file called 144.ra in this location:
I would give it 644 (world readable) file permissions to make
sure it can be accessed via a Web client. To establish a metafile pointing
to it, I would create the file /home/tjk/public_html/test.ram (note
the file extension .ram) and give it file permissions
644 (world readable).
For use of RTSP (Real Time Streaming Protocol) and SureStream
encoding, which are supported on this
server, you may refer to a file using a line like this:
(NOTE: There is no tilde (~) in the URL !!! Also note that the older "pnm" protocol is deprecated under Helix 11.)
This instructs a RealAudio server to make available the audio stream originating from server jan.ucc.nau.edu and from the file /home/tjk/public_html/144.rm (again, note that the BaseDirectory is /home, so that /home never shows up in the actual path to the RealAudio .rm file!). If I wish to stream more than one RealAudio file in succession, I would add a second line to my test.ram file.
To refer to this via a URL, I would use the following syntax:
Listen to my RealAudio output, click <A HREF="test.ram">here</A>
or, you can just include the path to the sing;e media file; here is an actual such link: RTSP stream. For more information on linking in RealAudio files, consult this link.
To summarize, use .ram as the suffix to a file that points to the media file, use .ra for regular Real Audio files, and use .rm for Real Media (streaming via the RTSP protocol) files. More information can be found elsewhere on how to define or interpret different MIME types.
Note that typically if you only want files to be able to be served in streaming
mode, they should not be anywhere under one's public_html area or else anyone can still access them using a standard Web browser via http. The creation
of a subdirectory outside of the public_html area precules standard Web access
to such files.
The Quicktime movie format is supported under Helix 11, which runs on jan (www2.nau.edu), sapphire (www.nau.edu), and dana.
Streaming MP3 Files
For additional information on RealAudio and RealVideo, please consult the Progressive Networks technical help pages. "jan.ucc.nau.edu" is running a 60-stream RealAudio/RealVideo Helix 11 server. For details on particular features available with this server, consult this link or this link.