IBM MPEG-4 XMT-O Tutorial IBM MPEG-4 Technologies
IBM MPEG-4 Technologies
Overview
Presentation
Images
Text
Definitions
Regions
Animation
Transition
Credits
Transition credits
Video

Add Text

This exercise will demonstrate how to add text to the presentation. Titles, for the pictures, are added in the title location below the pictures.

The text description of each picture is specified using the <string> element. The text is placed in the textLines attribute. The text corresponds to the various pictures added in the previous exercise. Timing is specified in event timing. The begin and end of the text is relative to the timing of the pictures.

There is an additional quotation mark in the textLines attribute. XML uses the quotation mark to delineate the value of the attribute tags, in this case the textLines attribute. XMT-O also uses the quotation mark to indicate multiple strings in the attribute, in this case it would be used to distinguish multiple lines of text. Thus the textLines attribute has nested quotation mark. In order to escape the MPEG-4 quotation mark use the XML character escape for the quotation mark, &quot;. You could also use double quotation mark nested in single quotation mark, for example textLines=' "Queen Marry" ', but this is non-canonical XML and as such my not be supported by all tools.

<xmt-o ...>
  <head> ... </head>
  <body>
    <par>
      ...
      <string id="text1" begin="slide1.begin" end="slide1.end" textLines="&quot;Queen Mary&quot;"/>
      <string id="text2" begin="slide2.begin" end="slide2.end" textLines="&quot;Montpellier Park&quot;"/>
      <string id="text3" begin="slide3.begin" end="slide3.end" textLines="&quot;Aigues Mortes&quot;"/>
      <string id="text4" begin="slide4.begin" end="slide4.end" textLines="&quot;Hong Kong&quot;"/>
    </par>
  </body>
</xmt-o>

The <material> element supports the fill characteristic of an object and the object's color. The color can be specified as a color string or as hexadecimal value as we saw earlier.

The font is specified by the <fontStyle> element. The family is a list of strings where the client font family support is searched according to the specified list. SANS, SERIF and TYPEWRITER font families are supported by default on all MPEG-4 clients.

The location of the text is specified by the <transformation> element.

<xmt-o ...>
  <head> ... </head>
  <body>
    <par>
      ...
      <string ...>
        <material color="black" filled="true"/>
        <fontStyle family="&quot;SANS&quot;" justify="MIDDLE; MIDDLE" size="18" style="BOLD"/>
        <transformation translation="0 -126"/>
      </string>
      <string ...>
        <material color="black" filled="true"/>
        <fontStyle family="&quot;SANS&quot;" justify="MIDDLE; MIDDLE" size="18" style="BOLD"/>
        <transformation translation="0 -126"/>
      </string>
      <string ...>
        <material color="black" filled="true"/>
        <fontStyle family="&quot;SANS&quot;" justify="MIDDLE; MIDDLE" size="18" style="BOLD"/>
        <transformation translation="0 -126"/>
      </string>
      <string ...>
        <material color="black" filled="true"/>
        <fontStyle family="&quot;SANS&quot;" justify="MIDDLE; MIDDLE" size="18" style="BOLD"/>
        <transformation translation="0 -126"/>
      </string>
    </par>
  </body>
</xmt-o>

The following is the complete XMT-O file used for this exercise:

 IBMSlideShow3.xml

Here is a snap shot of the exercise:


In the next exercise, you will use definitions to share the text fontstyle and material.

 

  IBM Home | Research Home | MPEG-4 Technologies | alphaWorks | © Copyright IBM Corp. 1998, 2006. All Rights Reserved.