FAQ: META FILES

Meta files and how to use them

A meta file is a small text file which is used to link to streaming media.

There are several reasons why they are used:

a) Web browsers such as Internet Explorer and Netscape Navigator were created before streaming, and consequently there was no need to incorporate ways to link to streaming media. Meta files were a work around from this original problem, as they allow the players to be spawned from the web page.

b) Although it is easy to make clerical errors when setting up meta files, it is easier to update them if a streaming server is moved or updated as individual web pages do not need to be changed.

c) QuickTime inherently is more difficult to link to from a web page. At PlanetStream, we have updated our servers with the necessary MimeTypes which enables us to provide links to .qtl files which spawn the QuickTime player.

Real
The following link:
http://links.planetstream.com/demo/animationmodem.ram
is to the meta file that contains the text:
rtsp://merlin.planetstream.com/demo/animationmodem.rm

They look very similar, but you will notice that
a) The link to the meta file ends in .ram - This tells the browser to open up the Real Player
b) The meta file begins with RTSP - this tells the player that it should use the Real Time Streaming Protocol
c) The meta file ends in .rm - This is the actual file which contains the audio/video content.

Windows Media Player
The following link:
http://links.planetstream.com/demo/businesscentre56.asx
is to the meta file (a text file) that contains the text:

<asx version = "3.0">
<entry>
<ref href = "mms://merlin.planetstream.com/demo/32.wmv" />
</entry>
<entry>
<ref href = "http://merlin.planetstream.com/demo/32.wmv" />
</entry>
</asx>

This is slightly different from the above and allows for the failover to http streaming if the mms port is closed by a firewall (If you only specified the mms protocol Windows Media Player would not roll over to http streaming by default).

a) The link to the meta file ends in .asx - This tells the browser to open up Windows Media Player
b) The asx version is given, and then two seperate entries to link to the streaming file. Notice that the two entries given are mms - the preferred and higher quality option, but if that is not available a second entry for streaming over http is given.

QuickTime
QuickTime has different ways to link to its files, or embed them in webpages. We supply links, and prefer to do it in the following way.
The following link
http://links.planetstream.com/demo/animationmodem.qtl
is to a meta file that contains the following text:

<?xml version="1.0"?>
<?quicktime type="application/x-quicktime-media-link"?>
<embed src="rtsp://merlin.planetstream.com/demo/animationmodem.mov" />

This is an xml file which functions in the same way as for Real and Windows Media Player, but requires the initial definitions to be setup. It is also necessary to add the qtl mime type to the hosting webserver (This is not a standard function of many ISP's).