SMIL DTD
From: http://dejavu.cs.vu.nl/~symm/validator/SMIL10.dtd
<!--

    This is a draft and experimental XML document type 
    definition for SMIL 1.0.  
  
        Draft:  $Date: 1997/11/06 14:38:15 $ ($Revision: 1.3 $)

        Author: Jacco van Ossenbruggen <jrvosse@cwi.nl>
  
    This is work in progress, subject to change at any time.
    Further information about SMIL 1.0 is available at:

          http://www.w3.org/AudioVideo/

-->

<!--=================== SMIL Document =====================================-->
<!--
     The root element SMIL contains all other elements,
     The lipsync attribute here provides a global default 
     for the lipsync attribute of the par elements.
     A default for this global attribute is implementation dependent:
-->
<!ELEMENT smil (head?,body?)>
<!ATTLIST smil
        id      ID              #IMPLIED
        lipsync (true|false)    #IMPLIED
>

<!--=================== The Document Head =================================-->
<!ENTITY % layout-section "layout|switch">
<!ENTITY % head-element "%layout-section;">

<!ELEMENT head ((%head-element;)*)>
<!ATTLIST head id ID #IMPLIED>


<!--=================== Layout Element ====================================-->
<!ELEMENT layout ANY>
<!ATTLIST layout
        id   ID         #IMPLIED
        type CDATA      "text/smil-basic"
>


<!--=================== Tuner Element =====================================-->
<!ELEMENT tuner EMPTY>
<!ATTLIST tuner
        id      ID      #REQUIRED
        left    CDATA   "0"
        top     CDATA   "0"
        z       CDATA   "1"
        height  CDATA   #IMPLIED
        width   CDATA   #IMPLIED
>



<!--=================== The Document Body =================================-->
<!ENTITY % media-object "audio|video|text|img|ref">
<!ENTITY % schedule "par|seq|(%media-object;)">
<!ENTITY % inline-link "a">
<!ENTITY % out-of-line-link "hlink">
<!ENTITY % link "%inline-link;|%out-of-line-link;">
<!ENTITY % container-content "(%schedule;)|switch|(%link;)">
<!ENTITY % body-content
"(%out-of-line-link;)*,(%schedule;|switch),(%out-of-line-link;)*">

<!ELEMENT body (%body-content;)>
<!ATTLIST body id ID #IMPLIED>


<!--=================== Synchronization Attributes ========================-->
<!ENTITY % sync-attributes "
        begin   CDATA   #IMPLIED
        end     CDATA   #IMPLIED
">

<!--=================== The Parallel Element ==============================-->
<!-- The default for par's lipsync attribute is the value 
     of the lipsync attribute of the SMIL root element.
-->
<!ENTITY % par-content "%container-content;">
<!ELEMENT par    (%par-content;)*>
<!ATTLIST par    
        id      ID              #IMPLIED
        lipsync (true|false)    #IMPLIED
        endsync CDATA           "last"
        dur     CDATA           #IMPLIED
        repeat  CDATA           "1"
        %sync-attributes;
>

<!--=================== The Sequential Element ============================-->
<!ENTITY % seq-content "%container-content;">
<!ELEMENT seq    (%seq-content;)*>
<!ATTLIST seq    
        id      ID      #IMPLIED
        dur     CDATA   #IMPLIED
        repeat  CDATA   "1"
        %sync-attributes;
>

<!--=================== The Switch Element ================================-->
<!-- In the head, a switch may contain only layout elements,
     in the body, only container elements. However, this
     constraint cannot be expressed in the DTD (?), so
     we allow both:
-->
<!ENTITY % switch-content "layout|(%container-content;)">
<!ELEMENT switch (%switch-content;)*>
<!ATTLIST switch id ID #IMPLIED>

<!--=================== Media Object Elements =============================-->
<!-- SMIL only defines the structure. The real media data is 
     referenced by the href attribute of the media objects.
     The media objects have the following link attributes 
     for XML linking compatibility:
-->
<!ENTITY % mo-XML-link-atts '
        xml-link        (simple)        #FIXED "simple"
        show            (embed)         #FIXED "embed"
        actuate         (auto)          #FIXED "auto"
        inline          (true)          #FIXED "true"
'>

<!-- Furthermore, they have the the following attributes as defined
     in the SMIL draft
-->
<!ENTITY % mo-attributes "
        href    CDATA   #REQUIRED
        type    CDATA   #IMPLIED
        loc     CDATA   #IMPLIED
        id 	ID 	#IMPLIED
        dur	CDATA	#IMPLIED
        repeat	CDATA	'1'
        %sync-attributes;
        %mo-XML-link-atts;
">

<!-- All info is in the attributes, media objects are empty elements: -->
<!ELEMENT audio EMPTY>
<!ELEMENT video EMPTY>
<!ELEMENT text  EMPTY>
<!ELEMENT img   EMPTY>
<!ELEMENT ref   EMPTY>

<!ATTLIST audio %mo-attributes;>
<!ATTLIST video %mo-attributes;>
<!ATTLIST text  %mo-attributes;>
<!ATTLIST img   %mo-attributes;>
<!ATTLIST ref   %mo-attributes;>


<!--=================== Link Elements =====================================-->
<!-- These should all conform to the XML linking elements -->


<!--=================== Inline Link Element ===============================-->
<!ELEMENT a (%media-object;|seq|par|switch)*>
<!ATTLIST a
        href            CDATA                   #REQUIRED
        id              ID                      #IMPLIED
        role            CDATA                   #IMPLIED
        content-role    CDATA                   #IMPLIED
        content-title   CDATA                   #IMPLIED
        behavior        CDATA                   #IMPLIED
        show            (replace|new|pause)     "replace"
        xml-link        (simple)                #FIXED "simple"
        actuate         (user)                  #FIXED "user"
        inline          (true)                  #FIXED "true"
>

<!--=================== Out-of-line Link Element ==========================-->
<!ELEMENT hlink (anchor,anchor)>
<!ATTLIST hlink
        id ID #IMPLIED
        show            (replace|new|pause)     "replace"
        role            CDATA                   #IMPLIED
        content-role    CDATA                   #IMPLIED
        content-title   CDATA                   #IMPLIED
        behavior        CDATA                   #IMPLIED
        xml-link        (extended)              #FIXED "extended"
        actuate         (user)                  #FIXED "user"
        inline          (false)                 #FIXED "false"
>


<!--=================== Anchor Element ====================================-->
<!ELEMENT anchor EMPTY>
<!ATTLIST anchor 
        id              ID                      #IMPLIED
        href            CDATA                   #REQUIRED
        role            (src|dst)               #REQUIRED
        behavior        CDATA                   #IMPLIED
        xml-link        (locator)               #FIXED "locator"
        actuate         (user)                  #FIXED "user"
>