SMIL 2'0 XML for Web Multimedia

1
SMIL 2.0 XML for Web Multimedia

• Internet Computing, IEEE , Volume 5 Issue5 ,
  Sep/Oct 2001, Page(s) 78 -84
• Lloyd Rutledge
• http//www.cwi.nl/lloyd/Papers/Spotlight/
• Speaker Chih-Wen Tien

2
SMIL Introduction

• Synchronized Multimedia Integration Language
• XML family
• World Wide Web Consortium (W3C)
• http//www.w3.org/AudioVideo/
• SMIL 1.0 1998/06/15
• SMIL 2.0 2001/08/07

3
SMIL Introduction

• CWI
• Centrum voor Wiskunde en Informatica
• http//www.cwi.nl/media/SMIL/
• The Rise and Fall of Multimedia Authoring
• http//www.cwi.nl/lynda/publications.html
• CMIF (CWI Multimedia Interchange Format)
• CMIFed (CMIF editor)
• GRiNS A GRaphical INterface for creating and
  playing SMIL documents
• http//www7.scu.edu.au/programme/fullpapers/1939/c
  om1939.htm
• Oratrix
• GRiNS Pro Editor for SMIL 2.0
• GRiNS Player for SMIL 2.0
• http//www.oratrix.com/Demos

4
SMIL Introduction

• What it is
• XML for Web Multimedia
• A collection of XML elements and attributes used
  to integrate media objects for presentation in
  local and network-based environments and describe
  their temporal and spatial relationship during
  presentation.
• Not focus on decoding engines and formats for any
  one media type, but on media temporal and spatial
  relationship during presentation.

5
SMIL Profiles

• SMIL 2.0 Language Profile
• SMIL Basic
• XHTMLSMIL
• Animated SVG

6
SMIL Profiles

• SMIL 2.0 Players
• Oritrax GRiNS Player for SMIL 2.0, RealNetwork
  RealOne Player
• Full support for the SMIL 2.0 Language profile
• Microsoft Internet Explorer 6.0
• Support for the XHTMLSMIL profile

7
SMIL Profiles

• General structure of a SMIL 2.0 Language Profile
  document

8
SMIL Profiles

• SMIL 2.0 Language Profile
• XML encoding string (encoding attribute)
• XML namespace declaration (xmlns attribute)
• ltheadgt element
• Layout and transition declarations as well as
  mateinformation and custom test attribute
  definitions
• ltbodygt element
• timing, media, and other declarations

9
SMIL 2.0s Features

• Media Content
• Layout
• Transition
• Timing
• Adaptivity (Content Control)
• Linking

10
Media Content

• Media object declaration and reference

11
Media Content

• SMIL does not create media, but rather integrates
  existing multiple media into a single
  presentation and controls how the media will be
  presented.
• ltrefgt, ltimggt, ltvideogt, ltaudiogt, lttextgt,
  ltanimationgt and lttextstreamgt elements
• src attribute

12
Layout

• SMIL layout model

13
Layout

• Layout structure

14
Layout

• Layout elements and attributes
• ltlayoutgt element
• lttopLayoutgt element defines a presentation
  windows.
• ltregiongt element
• top, bottom, left, right, height, and width
  attributes
• fit(fill hidden meet scroll slice)
• Assign region attributes to media object elements
  and indicate the region in which they'll play.

15
Layout

• SMIL supports a direct layout model for managing
  a presentation's visual and audio rendering
  space.
• HTML uses an indirect layout model via cascading
  style sheets (CSS).
• Multiple top-level windows let a presentation
  segment control and render operations in
  different parts of the screen.

16
Layout

• The support for subregion positioning can place
  an object at a particular (X, Y) offset within a
  region or aligned to a registration point.
• SMIL 2.0 supports multiple objects to be active
  in a region simultaneously.
• The alignment mechanism can center a set of media
  objects of varying size at a specific point in a
  region.

17
Transition

• Transition structure

18
Transition

• Play when media start and stop.
• Define the transitions in the ltheadgt section and
  reference them in the ltbodygt section as either
  input or output transition on a media object
  (transIn and transOut attributes)
• Timing properties (dur attribute) and
  transition-specific properties (direction
  attribute)

19
Timing

• Without SMIL, XML-defined Web presentations are
  static.
• With SMIL, XML presentations change over time,
  with or without user interaction.

20
Timing

• Timing elements (time containers) (1/4)
• Timing elements dominate the hierarchical
  composition of the document body.
• ltseqgt time container
• Children elements play in sequence, one after the
  other, in composition order
• Greeting Section and Thumbnail Section
• ltpargt time container
• Children elements play in parallel

21
Timing

• Timing elements (3/4)
• ltexclgt (exclusive) time container
• Childrens default begin time is indefinite.
• Children play one at a time, in any order.
• Active (interrupted) element, interrupting
  element and pause queue
• Whenever one child is triggered to begin, other
  playing siblings stop

22
Timing

• Timing elements (3/4)
• ltexclgt structure
• ltexcl dur"indefinite"gt
• ltpriorityClass id"ads" peers"defer"gt
• ltvideo id"advert1" .../gt
• ltvideo id"advert2" .../gt
• lt/priorityClassgt
• ltpriorityClass id"program" peers"stop"
  higher"pause"gt
• ltvideo id"program1" .../gt
• ltvideo id"program2" .../gt
• ltvideo id"program3" .../gt
• ltvideo id"program4" .../gt
• lt/priorityClassgt
• lt/exclgt

23
Timing

• Timing elements (4/4)
• ltpriorityClassgt element
• peer(stop pause defer never)
• higher(stop pause)
• lower(defer never)

24
Timing

• The default begin time varies with the parent
  time container.

25
Timing Attributes

• begin and end attributes
• Default start time (time base)
• A child of a ltpargt would start/end at a set time
  after the ltpargt begins and a ltseqgt child would
  start/end at a set time after its previous
  sibling ends
• dur attribute
• Explicit duration
• Implicit duration
• Line 23 begin1s
• Line 20 endgreet.end1s
• Line 40 durindefinite, no scheduled stop time,
  event

26
Timing

• begin and end attributes
• Support for multiple begin and end values.
• The first satisfied begin or end value will
  trigger the element to start or end.
• Can mix scheduled and event-based values.
• begin3s button.activateEvent

27
Timing

• restart(always whenNotActive never
  default)
• Document tree
• restartDefault attribute
• Defines the default value for the restart
  behavior for an element and all descendents.  
• restartDefault(always whenNotActive never
  inherit)
• If there is no parent element, the value is
  "always".

28
Timing

• Various SMIL 2.0 duration concepts
• The inherent duration is the duration of media
  object.
• The simple duration is the inherent duration
  modified by the dur attribute.
• The active duration is the simple duration
  modified by the repeatCount (and repeatDur)
  attributes.
• The perceived duration is an elements visual
  behavior after its active duration and before its
  parent time container ends.

29
Timing

• Inherent duration
• Discrete media (0 second)
• Continuous media
• dur attribute
• Specifies the (explicit) simple duration.
• dur(Clock-value media indefinite)

30
Timing
Simple duration table
31
Timing

• repeatCount attribute
• Define an iteration factor of the elements
  simple duration.
• repeatCount(numeric value indefinite)
• repeatDur attribute
• Define a duration for all the repeated
  iterations.
• repeatDur(Clock-value indefinite)

32
Timing

• min and max attributes
• Define a lower or upper bound on the active
  duration.
• min(Clock-value media), default value 0
• max(Clock-value media indefinite)

33
Timing

• Active duration algorithm (1/3)
• B The begin of an element.
• d The simple duration of an element.
• PAD The preliminary active duration of an
  element, before accounting for min and max
  semantics.
• AD The active duration of an element.

34
Timing

• Active duration algorithm (2/3)
• If end is specified, but dur, repeatDur, and
  repeatCount are unspecified,
• if end is resolved to a value, then PAD end
  - B,
• else, if end is indefinite, then PAD
  indefinite,
• else, if end is unresolved, then PAD is
  unresolved
• else, if end is unspecified, or end indefinite,
  then PAD IAD 
• Otherwise, an end value not equal to indefinite
  is specified along with at least one of dur,
  repeatDur, and repeatCount, then
• PAD MIN( IAD,  end - B)
• If min is specified, substitute a value of 0.
• If max is specified, substitute a value of
  "indefinite.
• AD MIN( max, MAX( min, PAD ))

35
Timing

• Active duration algorithm (3/3)
• Intermediate Active Duration Computation (IAD)
• p0 The simple duration from the Simple Duration
  Table
• p1 indefinite, if repeatCount is unspecified
• p2 indefinite, if repeatDur is unspecified
• If p0 0, IAD 0,
• else if repeatCount and repeatDur are
  unspecified, IAD p0
• else IAD MIN( p1, p2, indefinite)

36
Timing

• fill attribute
• Specify an element to be extended beyond the
  active duration by freezing the element final
  state (until its parent time container ends).
• fill(remove freeze hold transition auto
  default)
• fillDefault attribute
• Defines the default value for the fill behavior
  for an element and all descendents. 
• fillDefault(remove freeze hold transition
  auto inherit)

37
Timing

• endsync attribute
• Specify that the entire ltpargt or ltexclgt ends when
  the first child ends, the last child ends, or a
  named child end.
• endsync(first last Id-value all media)

38
Timing

• Controlling runtime synchronization
• syncBehavior(canSlip locked independent
  default)
• syncTolerance(Clock-value default )
• syncMaster()
• syncBehaviorDefault(canSlip locked
  independent inherit)
• syncToleranceDefault(Clock-value inherit )

39
Timing

• Events
• Combination with begin and end attributes
• Rules
• Combination with the ltexclgt element provides a
  powerful mechanism for conditional content
  activation.

40
Timing

• XML Integration
• timeContainer ( par seq excl none )
• When interating SMIL timing into other XML
  languages, we can declare XML elements to have
  time container semantics.
• timeAction ( intrinsic display visibility
  style class none )
• Allows the author to specify what it means to
  apply timing to a given element.

41
Adaptivity

• ltswitchgt structure

42
Adaptivity

• Content control elements and attributes
• ltswitchgt element
• Media objects, timing containers, nested ltswitchgt
  elements, or ltlayoutgt elements
• The browser examines the children in composition
  order.
• Once it finds a child that passes the tests for
  playability, it selects that child for play and
  ignores all the others
• Predefined system test attributes
• State the conditions that must be true for an
  element to be played
• systemLanguage, systemCaptions, systemBitrate,
• User-defined system test attributes
• Test attributes can be used inline (outside the
  ltswitchgt element).

43
Adaptivity

• User-defined System Test Attributes Structure
• ltsmilgtltheadgt    ltcustomAttributesgt       
  ltcustomTest id"west-coast /gt    lt/customAttrib
  utesgtlt/headgtltbodygt    ltswitchgt       ltaudio
  src" customTest"west-coast"/gt         
  ...    lt/switchgtlt/bodygt
• lt/smilgt

44
Linking

• Provide the navigation paths for users to
  traverse through Web multimedia.
• ltagt element (lines 41 through 51)
• href attribute and the character

45
Animation
46
SMIL 2.0 Part 1 Overview, Concepts, and
Structure

• Multimedia, IEEE , Volume 8 Issue 4 , Oct-Dec
  2001, Page(s) 82 -88
• Dick C.A. Bulterman

47
SMIL 2.0 Design Goals

• Extend SMIL 1.0's functionality
• Support for increased interaction, enhanced
  timing semantics, extended content control and
  layout facilities, and new animation and
  transitions primitives.
• Maintain a declarative, XML format
• Introduce a module-based structure
• More than 50 modules
• Module reuse
• Integrate parts of SMIL 2.0 into other XML-based
  languages

48
What it isn't

• SMIL 2.0 isn't a Flash substitute
• SMIL 2.0 doesn't define any particular type of
  media, but describes media composition.
• A SMIL presentation can include Flash objects.

49
What it isn't

• SMIL 2.0 isn't an MPEG-4 substitute.
• MPEG-4 is a family of protocols that covers a
  wide range of media-related concerns but not a
  specific solution to any one class of media
  presentation.
• Extensible MPEG-4 Textural (XMT)
• Coordinate the development of SMIL 2.0 and MPEG-4

50
What it isn't

• SMIL 2.0 isn't a Dynamic HTML substitute
• D-HTML introduces local time and animation
  effects into static HTML Web pages.
• SMIL's scope is much broader than the local
  nature of D-HTML.

51
SMIL 2.0s Functional Groupings of Elements and
Attributes
52
SMIL 2.0 Part 2 Examples and Comparisons

• Multimedia, IEEE , Volume 9 Issue 1 ,
  Jan-Mar 2002, Page(s) 74 -84
• Dick C.A. Bulterman

53
Modularization

• Like XML, SMIL is a metalanguage used to create
  other languages.
• Combine SMIL 2.0s modules into a profile -- a
  tailored final-form language for multimedia
  presentation.
• SMIL profiles
• SMIL 2.0 Language Profile, SMIL Basic,
  XHTMLSMIL, and animated SVG

54
SMIL 2.0 Implementation Profiles

• SMIL 2.0 language, SMIL basic, SMIL animation,
  and XHTMLSMIL
• The SMIL 2.0 language and basic profiles are part
  of the SMIL 2.0 specification.
• Third Generation Partnership Project (3GPP)
  consortium has used the SMIL basic profile as
  basis for the wireless multimedia specification
• XHTMLSMIL
• integration into Microsoft' Internet Explorer 5.5
  and 6.0 browsers

55
The Profile Models Goal

• Customize the integration of SMIL's functionality
  into various XML-based languages without
  requiring language authors to learn totally new
  timing semantics for each variant.

56
SMIL 2.0 Basic Profile

• Support SMIL on telephones, PDAs,
• Differences
• The module functionality set and The complexity
  of the document structure

57
XHTMLSMIL Profile

• Integrate SMIL timing and presentation semantics
  in other, nontemporal XML documents.
• IE 5 provided SMIL support based on SMIL 1.0
  using Microsoft's time behaviors.
• IE 5.5 and IE 6 provide support based on the SMIL
  2.0 using the time2 behaviors.
• IE doesn't support timed hyperlinks or any of the
  SMIL layout modules.

58
XHTMLSMIL Profile Structure
59
XHTMLSMIL Profile

• The outer document element isn't ltsmilgt but
  lthtmlgt
• The lthtmlgt element contains an XML namespace
  declaration for the "t" prefix used to denote
  SMIL's HTML extensions.
• The ltheadgt contains a short-hand style definition
  for the time2 behavior, plus an import tag
  pointing to the implementation.
• The ltbodygt contains a sequence of images
  displayed according to SMIL's sequential time
  container semantics

60
SVG with SMIL 2.0 animation

• Reuse limited portion of the language.
• Packaged SMIL animation as the SMIL 2.0 Animation
  Recommendation.
• SMIL timing and animation have been integrated
  into the SVG model by Adobe.

61
Using SMIL 2.0
62
Conclusion

• SMIL 2.0 players, editors, and other tools
• http//www.w3.org/AudioVideo