Guidelines for Creating SMIL Files

SMIL is very similar to HTML, however enough differences exist that it can become frustrating for new developers, particularly because there is a lack of full-featured editing tools. The following guidelines will help minimize confusion when working with SMIL tags.

• SMIL tags and attributes must be lowercase, and a tag that does not have a corresponding end tag (for example, the <smil> tag has the corresponding end tag </smil>) must close with a forward slash. For example:
  <audio src="first.rm"/>
  
• Attribute values, such as first.rm in the preceding paragraph, must be enclosed in double quotation marks. Each file name in SMIL must reflect the file name exactly as it appears on the server. Note, file names can use uppercase, lowercase, or mixed case.
  
• Save your SMIL file with the extension .smil or .smi. The .smil extension is preferable, as it reduces the potential for conflict with other files. Do not include spaces in the file name. For example, you can have the file my_presentation.smil but not my presentation.smil
  
• Use the ascii character codes (the same as those used in HTML) for quotation marks, apostrophes, ampersands, or angle brackets for content in a SMIL header, such as a presentation title.
  
• As in HTML, the SMIL comment tag starts with <!-- and ends with -->. The ending does not include a forward slash:
  <!--This is a comment-->
  
• Be very careful of misplaced commas, spaces, line breaks, and so forth in your SMIL file. Media players are much less forgiving of these types of errors than current Web browsers, and even a single syntax mistake can cause your entire presentation to crash.