SMIL: Synchronized Multimedia Integration Language
Lloyd Rutledge and Lynda Hardman
Multimedia and Human-Computer Interaction Group CWI: Centrum voor Wiskunde en Informatica Amsterdam, The Netherlands W3C SYMM working group
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
The Problem: Multimedia
Lots of Bits Images, audio and video are beyond Internet design specs Results in space/time constraints at: - the server - the network(s) - the client Not All Bits are Equally Important Time between samples often more important than bits in sample, for example lip synchronization (but not always...) Content may be Distributed Across Network Need to synchronize presentation
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL
Synchronized Multimedia Integration Language
SMIL is about timing...
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL
Synchronized Multimedia Integration Language
SMIL is about timing...
not just graphics...
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL
Synchronized Multimedia Integration Language
SMIL is about timing...
not just graphics...
combining Web resources...
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL
Synchronized Multimedia Integration Language
SMIL is about timing...
not just graphics...
combining Web resources...
in an XML syntax
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Synchronized Multimedia Integration Language (SMIL)
Main Points Pronounced smile Multimedia for the Web for multimedia what HTML is for hypertext Integration format for presentable mono-medium formats Structure SMIL 2.0 is a meta-language SMIL Profile, SMIL Basic and XHTML+SMIL set as among possible subsets Status SMIL 1.0 became W3C Recommendation on 15th June 1998 SMIL 2.0 is now in Last Call and will become a W3C Recommendation soon - includes SMIL Profile and SMIL Basic XHTML+SMIL comes after SMIL 2.0 Main themes Powerful timing and synchronization Adaptive to users and systems Models a flexible but consistent presentation and user interface
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL Applications
Infotainment
Accessibility
Conceptual Art
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL 2.0 extension over SMIL 1.0
Much Much More SMIL 1.0 spec is 30 pages, SMIL 2.0 spec is 300 pages Animation Values of SMIL constructs change over time Enables more vibrant presentation Incorporation with SVG Timing Integration Use of SMIL constructs in other document sets Enables, for example, HTML+SMIL in Internet Explorer Raises issues of semantic significance of hierarchy Broadcasting/streaming No preload or full download Use of non-predictive events in timing Need to maintain hard synchronization Large potential use of SMIL
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL 2.0 Modules
SMIL is broken up into separate modules Thus not all of SMIL 2.0 needs to be used in one instance The SMIL 2.0 Sections of Modules are: Animation Content Control selection, adaptation and optimization Layout Linking navigation Media Object media content that is integrated into presentation Metainformation machine-processible data about the presentation Structure base elements for high-level SMIL structure Timing and Synchronization ~100 pages!! Time Manipulations speed of integrated media Transition Effects fades and wipes
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL 2.0 Profiles
What is a profile? A language for which a browser can be built A combination of modules from the SMIL 2.0 meta-language Possibly non-SMIL constructs with SMIL constructs SMIL 2.0 Language Profile (SMIL Profile) What is typically thought of as SMIL 2.0 Most of SMIL 2.0 features in one profile SMIL 2.0 Basic Language Profile (SMIL Basic) Intented for mobile devices Assumes restricted processing ability XHTML+SMIL Applies timing to text-based display XHMTL-based layout SMIL 1.0 Backwards-compatable can be played on SMIL Profile browsers
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL Implementors
RealNetworks RealPlayer 8 time-focussed media types - Current SMIL 1.0 support, anticipated SMIL Profile support 3rd party creation tools Clear Leader for SMIL Players ORATRiX GRiNS authoring environment and free player - current SMIL 1.0 and anticipated SMIL Profile authoring - current free player for SMIL Profile Microsoft Internet Explorer 5.5 supports XHTML+SMIL prototype - support for XHTML+SMIL standard anticipated with its release Apple Quicktime 4.1 supports SMIL 1.0
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
A Sample Presentation
The Network News
On demand on your screen
Formatted text, video and audio
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Local anchor setup
Top Story: Growth of the World-Wide Web
Amsterdam
Graph appears during spoken commentary
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Remote Correspondent
Top Story: Growth of the World-Wide Web
Amsterdam
Los Angeles
First video finishes, second video plays
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Following a Link
Top Story: Growth of the World-Wide Web
Amsterdam
Los Angeles
At any point during the video the viewer can request extra information.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
CWI spin-off Oratrix
GRiNS market leader in SMIL authoring systems Distribution agreement with Real Networks Co-founder Oratrix prize-winning business plan for McKinseys New Venture 1998
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
So what do we need to specify?
Content
(part of) media item
Spatial layout
Alternative content
bandwidth task user characteristics
Semantic annotations
meta-data
Temporal layout
A story anchor
Links
source and destination
anchor A anchor
growth
remote
remote A remote
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL as XML Markup
Integration language Media elements referred to, not included SMIL is XML Defined with XML DTD Can be hand-authored Declarative language - attribute/value pairs Integrable with XML environments Relationship with Other W3C Recommendations Again, SMIL is XML Basic layout isomorphic and replacable with CSS Shares constructs with (X)HTML SMIL 2.0 Family languages enable new SMIL-based XML formats
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
XML
Foundation Syntax for all Documents
xxxxx xxxx=xxxx xxxx=xxxx
file
xxxxx xxxx=xxxx xxxx= text content
xxxxx xxxx=xxxx xxxx=
Document Type Definitions (DTDs)
smil
head layout par region
body
media file
seq
ref region src dur=##s
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
An XML (SMIL) Document
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE smil PUBLIC "-//W3C//DTD SMIL 1.0//EN" "http://www.w3.org/AudioVideo/Group/SMIL10.dtd"> <smil> <head> <meta name="sync" content="soft"/> <layout> <root-layout id="SMIL-" width="492" height="810"/> <region id="address-region" width="50%" height="8%"/> <region id="image-region" top="8%" height="91%"/> </layout> </head> <body> <seq> <par> <text type="text/plain" region="address-region" src="Herengracht284.txt" dur="2s"/> <img region="image-region" src="http://www.amsterdam.nl/bmz/adam/pics/h284.jpg"/> </par> <par> <text type="text/plain" region="address-region" src="Herengracht539.txt"/> <img region="image-region" src="http://www.amsterdam.nl/bmz/adam/pics/h539.jpg" dur="2s"/> </par> </seq> /body </smil>
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Content Instance of Media Item
I II
Media item, or part Extent, position and z-index
III Duration IV Alternate Content V Link end-points VI Associated semantics
We will return to all these points at the end.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Media Object Elements
ref, text, textstream, img, audio, video and animation
<ref src="anything.???" ... /> <text src="caption.html" ... /> <textstream src="stockticker.rtx" ... /> <img src="graph.jpg" ... /> <audio src="http://www.w3c.org/SYMM/joe-audio.wav" ... /> <video src="rtsp://www.cwi.nl/SMIL/video.rm" ... /> <animation src="cute.anim" ... />
video audio text images
The src attribute is a URI, locating the data. Names are for readability and are not used for determining data type.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Specification of part of media item
t x y text string t x y video (moving) area y
t x
image area t x y audio phrase
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Clips in time
Time and space treated independently. Spatial clipping done via region mechanism, discussed later Time restricted to a single extent - a contiguous section of a continuous media object can be specified
t1 duration
t2
The clipBegin and clipEnd attributes
<video src="the.news/mpeg/zoomin.mpv" clip-begin="smpte=00:01:19:20" clip-end="smpte=00:01:38:40" ... />
- syntax of values is ...
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
New Media Constructs in 2.0
Parameter Control Application of media-specific parameters to media playback Handling of repeat instrinsic to media What to do when media ends Media Clips Markers Use of media clips defined internally in media Brush Element Paints a solid color on the screen
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Spatial layout
Top Story: Growth of the World-Wide Web
Amsterdam
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Possible ways to specify layout
w.r.t. x,y axes
t
w.r.t. item
t
function of time
regions
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Region
Each media object instance contains a region reference: allows author to know where object will be played
<video src="anchor.mpg" region="V-main" />
The region is defined by: x,y W H and Z
<region id="V-main" top="5%" left="50%" height="100%" width="100%" z-index="3" /> <region id="V-remote" top="10" left="100" height="200" width="200" z-index="3" />
An id for each region is required. Its value is an XML identifier. Length values are percentage values or in pixels. The unit px may be omitted. The z-index gives the stacking order (highest integer stacks on top).
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
The WebNews Layout
Top Story: Growth of the
World-Wide Web
T-title root-layout
V-main
Amsterdam V-remote
T-anchor
Los Angeles
r_title
<layout> <root-layout width="721" height="587" id="matise" /> <region id="T_title" left="2%" top="5%" width="40%" height="24%" z-index=2 /> <region id="V-remote" left="3%" top="44%" width="54%" height="40%" z-index=3 /> ... </layout>
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Clips in space
The fit attribute
hidden (default) media item not scaled
hidden (default) media item not scaled
scroll media item not scaled
meet aspect ratio preserved
slice aspect ratio preserved
fill aspect ratio not preserved
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Layout Adaptation in SMIL
SMIL documents can adapt to devices with different screen sizes layout relative to the dimensions of the player's viewport alternative layout strategies Switch on layout and region Allow assigning test attributes to SMIL layout and region elements Examples - make room for subtitles - rearrange for varying screen size
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
New Layout Constructs in 2.0
Audio Control Adjustment of volume of integrated audio media Multiple Windows Regions placed in one of many windows Hierarchical Layout Regions placed within regions Introduced relative placement of regions Extended Adaptivity Adaptivity of layout components rather than choosing between layouts
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
(Potential) Use of CSS with SMIL
CSS in Current HTML Example: CSS with HTML Attribute transform A:link { Mapping to text-based presentation model color: blue; text-decoration:underline; Next step: applies to (text-based) XML } CSS in Current SMIL Alternative to SMIL Basic Layout - Not currently implemented Layout - isomorphic with CSS2 - CSS2 as alternative layout With embedded XML/HTML for text
A:visited { color: purple; text-decoration: underline; } P.Body { text-align: left; text-indent: 0.000000pt; margin-right: 18.000000pt; margin-left: 18.000000pt; font-size: 11.000000pt; font-weight: medium; SMIL Basic Layout Positions Entire Media font-style: Regular; Object color: #000000; If media object is XML, CSS2 can specify vertical-align: baseline; text-transform: none; objects appearance in its position font-family: Minion; CSS2 specifies aspects of object }
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
III Temporal Layout
A story
anchor
anchor A anchor
growth
remote
remote A remote
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Which time?
Types of time: media item time axis - video divided in frames, audio sampled at 44kHz duration document time - image starts at certain time and ends at a later time
start time
end time
run-time presentation - video data bits get caught up in network, so end time is delayed
start time
end time
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Duration of a media object element
Intrinsic derived from content of media item audio (or video) lasts 5.3 seconds intrinsic duration of discrete media, such as text or image, is zero. Explicit an explicit duration can be given The dur attribute, value is a clock-value or indefinite.
<video src="zoomin.mpv" region="V-main" dur="4s" />
media object stops after 4 seconds
<video src="zoomin.mpv" region="V-main" dur="6.5s" />
media object stops after 6.5 seconds - in this case, the audio track just stops and the last frame of the video remains
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Duration of a Media Object Element ctd.
An object can have its duration extended by repeating the content. The repeat attribute
<video src="zoomin.mpv" region="V-main" repeat="3" />
media object stops after 15.9 seconds
<video src="zoomin.mpv" region="V-main" repeat="3" dur="11s" />
media object stops after 11 seconds
<video src="zoomin.mpv" region="V-main" repeat="indefinite" />
media object stops when parent stops Attribute value of repeat is an integer or indefinite.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Start time of elementspar
The par element groups elements which are played in parallel Children of a par element are started at the same time
<par> <text src="leader_title.html" region="m_title" dur="5s" /> <video src="cnn.mpv" region="V-Main" /> <audio src="cnn.aiff" region="music" /> </par>
A story
anchor
anchor
The start time of a child of a par element is equal to the start time of the par element itself.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Start time of elementsseq
The seq element groups elements which are played sequentially Children are played one after the other, based on the textual order
<seq> <video src="logo.mpv" region="V-main" /> <video src="anchor.mpv" region="V-main" /> </seq>
A story
anchor
anchor
The start time of the first child of a seq element is the start time of the seq element itself. The start time of the next child is the end time of the previous child.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Par s and seqs can be nested
<seq> <par> <text src="leader_title.html" region="m_title" dur="5s"/> <video src="cnn.mpv" region="V-Main" /> <audio src="cnn.aiff" region="music" /> </par> <par> <text src="story_title.html" region="m_title" dur="2s" /> <video src="anchor.mpv" region="V-Main" /> <audio src="anchor.aiff" region="music" /> </par> <seq>
A story
anchor
anchor
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Explicit start time in a par element
The begin attribute, delay-value
<par> <text src="leader_title.html" region="m_title" dur="5s" /> <video src="cnn.mpv" region="V-Main" begin="1.4s" /> <audio src="cnn.aiff" region="music" /> </par>
A story
anchor
anchor
Video is delayed until 1.4s after the start of the par element.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Start time relative to another element
The begin attribute, event-value
<par> <text src="leader_title.html" region="m_title" dur="5s" /> <video id="v1" src="cnn.mpv" region="V-Main" begin="1.4s" /> <audio src="cnn.aiff" region="music" begin="id(v1)(0.5s)" /> </par>
A story
anchor
anchor
Audio is delayed until 0.5s after the start of video element v1.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
End time of media object element
A media object element with an implicit or explicit duration and a start time has an end = begin + duration.
<video src="cnn.mpv" region="V-Main" begin="4s" />
duration
anchor
begin
end
The end attribute. Syntax same as begin attribute. A media object element with an explicit start time and an explicit end has a duration = end - begin.
<text src="title.html" region="m_title" begin="4s" end="8s" />
duration
A story
begin
end
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
End time of par elementfirst
endsync par can end when the first element to finish ends
<par endsync="first"> <text src="leader_title.html" region="m_title" dur="5s" /> <video id="v1" src="cnn.mpv" region="V-Main" begin="1.4s" /> <audio src="cnn.aiff" region="music" begin="id(v1)(0.5s)" /> </par>
A story
anchor
anchor
end time par can end when the referenced element ends: id(Id-value) par can end when the last element to finish ends (default)
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
New Timing Constructs in 2.0
Animation Changing of numeric constructs over time such as region placement Applied to SVG Transitions Standard list of types, with timing Manipulation Changing of media playback speed Events List of DOM events that can trigger SMIL timing SMIL 1.0 restrictions lifted Long synchronization Negative begin times Much, much more ...
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Alternate content
... explosive growth of the WWW ...
audio
text
... explosive growth of the WWW ... ... explosieve groei van het WWW ... ... eksplozivni rast WWW ... ... crescita esplosiva della WWW ...
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Adaptation Issues
Adaptation for User Disabilities Language Previous knowledge Adaptation for Environment Delays: bandwidth, available CPU time Available processing: media peripherals, browser additional features Adaptation for Document Purpose Selection of appropriate content Media items have different meanings in different focus Progression of presentation to meet purpose W3C Web Accessibility Initiative (WAI) Guidelines for accessible (text-based) Web documents Meaningful values for attributes like alt, title, abstract and longdesc Meaningful content of link triggers (a element) How to apply these to a fixed timeline?
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Specifying Adaptation in SMIL
Temporal Adaptation Handling delays of download and processing Explicit and implicit time Temporal hierarchy of parallel and sequential composites - sets points in presentation progression for stronger sychronization switch Element At most one of the children of a switch element is played. The first acceptable element is chosen, so ordering should be best first. Works on anything the browser wants Test attributes can be combined skip-content Attribute How to adapt for SMIL dialects Ignore unknown elements within sub-tree or ignore whole sub-tree
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMIL Test Attributes
Selecting Content Alternatives system-bitrate bandwidth of Web connection - can switch media: video -> image -> text type mime type of media object system-required select if certain processing available Selecting for User system-language what language the user understands best system-captions show content if user want closed captioning (subtitles) - usually single content of switch (on or off) system-overdub-or-caption choice between audio or text Adaptive Visual Complexity system-screen-size, system-screen-depth Switch on structure, not content Extension Attributes for Particular Domain Wont be recognized by all browsers Potential examples knowledge level, audience profile, length of time
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Specifying alternative behavior
switch At most one of the children of a switch element is played. The first acceptable element is chosen, so ordering should be best first.
<switch> <audio system-bitrate="44000" src="hi-res.aiff" /> <audio system-bitrate="16000" src="low-res.aiff" /> </switch>
Test attributes can be combined.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
New Content Control in 2.0
Prefetch Control, timing, and adaptation of pre-loading media before its presentation Helps whole presentations progress with fewer hitches Custom Test Attributes Anyone can define adaptive test attributes for use in SMIL
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Linking
Top Story: Growth of the World-Wide Web
Amsterdam
Los Angeles
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Link from element to presentation
The <a> element similar to HTML <a> element. Source is unaffected and destination, href, is shown in new window.
<a show="new" href="archives-dcab.smi"> <video src="zoomin.mpv" region="V-Main" /> </a>
Top Story: Growth of the World-Wide Web
Amsterdam
Los Angeles
Source may also pause while destination is shown, or destination may replace the source (default).
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Link from element to element
Linking to SMIL fragments Destination element within another SMIL document uses # connector.
<a show="new" href="time-time.smil#XVII"> <text src="archives-dcab.html" region="I-Main" dur="indefinite" /> </a>
Destination presentation starts as if the presentation had been fast-forwarded to the beginning of the element designated by the fragment.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Link from element to subpart of media object
The area element The area element allows the specification of temporal and spatial subparts of a media object element. Spatial subparts use the coords attribute (similar to HTML image maps).
<video src="zoomin.mpv" region="V-Main" > <area id="mic" coords="40%, 70%, 55%, 100%" /> </video>
Defined w.r.t. media object, not w.r.t. region fit="slice" Order of coords is left-x, top-y, right-x, bottom-y. Temporal subparts use the begin and end attributes.
<video src="zoomin.mpv" region="V-Main" > <area id="graph-ref" begin="4.3s" end="6.8s" /> </video>
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Areas as source and destination of a link
href needed if used as source, id needed if used as destination
Source document (image in SMIL, area and link defined in SMIL): <img src="home-sweet.gif" region="I-Main"> <area href="time-time.smil#gable-3" show="new" coords="35%, 5%, 40%, 95%" /> </img> Destination document "time-time.smil" (image in SMIL): <img src="XVII.tiff" region="house-right" > <area id="gable-3" coords="30%, 0%, 70%, 100%" /> </img>
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Semantic annotations
SMIL 3.4. meta element defines properties of a document The name attribute is the property and the content attribute gives the value.
<meta name="title" content="Web News, 15th June 1998" /> <meta name="base" content="http://www.cwi.nl/SMIL/webnews/" />
The list of properties (values of name attribute) are open-ended. Attributes on par, seq and media object elements abstract, author, copyright, title (recommended) Attributes on media object elements alt (contains alternative text, recommended), longdesc (supplement to alt, but longer and should include descriptions of areas) Attributes on region elements title (recommended)
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
High-Level Structure of Document
Partitioning in Sections
<smil> <head> <meta> ... information about the document ... </meta> <layout> ... layout definition ... </layout> </head> <body> ... objects and temporal relations ... ... including links and area objects ... </body> </smil>
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Whats next?
SMIL 2.0 becomes a recommendation early in 2001 Draws attention to the standard Stabilized to enable wide-spread implementation and adoption First players scheduled for release with recommendation SMIL 2.0 becomes more implemented More browsers introduced More existing Web browsers add SMIL to languages shown SMIL browsers show more and more media - SVG? - All show XHTML? SMIL 2.0 becomes more used New Profiles Introduced from Outside W3C? SMIL 2.5 and 3.0?
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
SMILs Relationship with Other W3C Recommendations
SMIL Documents are XML Documents SMIL syntax is defined by an XML DTD Private Extensions must use Namespaces Skip-content attribute allows content of non-SMIL elements to be played System-required attribute states the subtree requires the named implementation SMIL Layout and CSS-2 SMIL basic layout is consistent with the visual rendering module in CSS-2 - it introduces the fit attribute - it is otherwise a subset. SMIL basic layout applies only to media object elements. SMIL media object elements refer to a region - CSS-2 region elements refer to the media object elements.
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Summary
Media object element revisited
<video id="vid1" region="R_video" src="rtsp://www.w3.org/CoolStuff.rm" clip-begin="smpte=00:01:19:20" clip-end="smpte=00:01:38:40" begin="3s" dur="22s" end="21s" alt="Video of Joe chatting to Tim" longdesc="Joe and Tim are in a meeting room. Joe is on the left and Tim is on the right" title="Joe greets Tim" system-bitrate="28800"> <area id="joe" begin="0s" end="5s" coords="0%,0%,50%,50%" href="http://www.w3.org/" /> <area id="tim" begin="5s" end="10s" coords="50%,50%,50%,50%" href="http://www.w3.org/Tim" /> </video>
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
Links
More info: http://www.cwi.nl/SMIL{/Tutorial} http://www.w3.org/TR/REC-smil http://www.w3.org/TR/smil20 http://www.oratrix.com/ http://www.real.com/
Copyright 2000 CWI (Centrum voor Wiskunde en Informatica), Amsterdam
