You can enhance your presentation's appeal by adding visual effects that occur when any type of visual clip starts or stops. With more than a hundred transition effects available, your streaming presentation can include special effects found in professional video production. You can also use transition effects to create a streaming slideshow from still images.
A transition occurs every time a clip starts or stops playing. If you do not use a
transition effect, the clip simply appears when it starts playing and, depending
on its fill
attribute, disappears when it stops playing. Using transition effects
makes these transitions more visually compelling. Instead of just appearing
onscreen, the clip might slowly fade in from a solid color. Or, a five-point star
might expand from the center of a region to reveal the clip. Instead of just
disappearing when it stops playing, a clip might crossfade into the clip that
plays next.
By default, each transition lasts one second, but you can make a transition last any length of time. Using transition effects does not affect a presentation's timeline. For example, a two-second transition applied to the end of a clip occurs during the last two seconds that the clip plays. If it is applied to the beginning of the clip, it occurs during the first two seconds of playback.
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For More Information: For instructions on doing this, see "Setting a Transition Effect's Duration". |
You can use a transition effect with any visual clip regardless of the layout you've defined, or whether another clip precedes or follows the clip that uses the effect. When a clip starts, the area it covers is treated as its background, whether that area is a region color, a clip in another region, or a clip in the same region. A transition effect simply introduces the clip over, or removes the clip from, its background. So when you use transitions with a sequence of clips, the clips do not have to be the same size.
Transition effects are distinct from the SMIL animations described in Chapter 17. A transition effect is a special effect that occurs when a clip starts or stops playing. An animation, on the other hand, is a special effect that occurs while a clip plays. You can use both transition effects and animations in the same presentation. You can even apply them to the same clip. But you define them separately.
A transition effect does not change a clip's audio level. If you slowly fade into a
video, for example, the audio plays normally throughout the fade. You can
change a clip's audio level, however, by animating the clip region's soundLevel
attribute. See "Controlling Audio Volume in a Region" for information about
soundLevel
. Chapter 17 describes SMIL animations.
Transition effects are applied to individual clips. Two clips playing in separate regions might end at the same time and use the same transition effect, such as a wipe transition that travels from left to right. In this case, two separate wipe transitions occur, one for each clip. Each transition effect is confined to the region in which the clip plays. You cannot make a single transition effect apply to both clips. For example, you cannot make the left-to-right wipe effect travel across the entire root-layout area, ushering in a new clip to each region as it passes over the region.
The following SMIL sample illustrates the functions and relationships of the tags used to create transition effects. The remainder of this chapter describes how to use these tags and their attributes to define and apply transition effects:
<smil xmlns="http://www.w3.org/2001/SMIL20/Language"> |
The SMIL file header section defines the transition effects your presentation uses. The following example defines three transition effects after the layout:
<head> |
Each transition is defined by a separate <transition/>
tag that typically has at
least three attributes, which are described in the following table.
Attribute | Function |
---|---|
id |
Sets a unique ID used to assign the transition to clips. For rules about creating IDs, see "SMIL Tag ID Values". |
type |
Identifies a group of transition effects. This attribute is required. |
subtype |
Determines which member of the transition type group is used. |
The following sections describe the various types and subtypes for transition effects. For convenience, the transition effects are grouped in families that share broad similarities, such as edge wipes and iris wipes. In defining a transition, you specify only the type and subtype, however.
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Note: Most transitions listed in the following sections have an SMPTE (Society of Motion Picture and Television Engineers) code. This code is provided for persons who want to find the SMIL transition effect that corresponds to a specific SMPTE transition. SMPTE codes are not used when defining SMIL transition effects, though. |
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Tip: To display samples of transition effects in RealOne Player, get the zipped HTML version of this guide as described in "How to Download This Guide to Your Computer". |
In the edge wipe family, an "edge" moves over the first clip, revealing the second clip. As an analogy, imagine a car covered with snow. As the windshield wiper moves, its edge reveals the underlying windshield. In these transitions, the edge may be different shapes, such as a straight line, a wedge, or a zigzag. The first subtype listed for each type in the following table is the default.
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These samples show all edge wipe transition effects run in the forward and reverse directions. |
A transition effect in the iris wipe family reveals a clip through an expanding shape. For example, a star can expand from the center of the transition area to reveal a new clip. The first subtype listed for each type in the following table is the default.
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These samples show all iris wipe transition effects run in the forward and reverse directions. |
The clock wipe family includes transition effects in which a clip is revealed by a radial sweep, similar to the second hand sweeping around the face of a clock. The first subtype listed for each type in the following table is the default.
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These samples show all clock wipe transition effects run in the forward and reverse directions. |
The matrix wipe family includes transition effects in which a clip is revealed by a series of sequential tiles that follow a pattern, such as a spiral. In the following table, the first subtype listed for each type is the default.
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These samples show all matrix wipe transition effects run in the forward and reverse directions. |
This transition family, which has no corresponding SMPTE codes, includes fades that let you blend images into one another, or fade an image into or out of a solid color. The push and wipe transition effects allow a second clip to push the first clip out of the way, or to slide over it. In the following table, the first subtype for a certain type is the default.
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Note: Push wipe transition effects are not currently functional in RealOne Player. |
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For More Information: With color fades, see See "Defining Colors and Border Blends" for information on color values. |
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This sample demonstrates all fade, push, and slide transition effects. |
The following sections describe optional <transition/>
tag attributes that
modify the appearance of the transition effects. The following table
summarizes these attributes.
Attribute | Value | Default | Function | Reference |
---|---|---|---|---|
borderColor |
blend| color_value |
black |
Defines the border color. | click here |
borderWidth |
pixels |
0 |
Specifies the border size. | click here |
direction |
forward|reverse |
forward |
Sets the direction of movement. | click here |
dur |
time_value |
1s |
Specifies the effect duration. | click here |
endProgress |
0.0-1.0 |
1.0 |
Halts the effect before it finishes. | click here |
fadeColor |
color_value |
black |
Sets the color for fade transitions. | click here |
horzRepeat |
integer |
1 |
Multiplies the effect horizontally. | click here |
startProgress |
0.0-1.0 |
0.0 |
Starts the effect at a midway point. | click here |
vertRepeat |
integer |
1 |
Multiplies the effect vertically. | click here |
By default, each transition effect lasts one second, but you can change this by
adding a dur
attribute to the <transition/>
tag. As described in "Timelines and
Transition Effects", changing a transition effect's duration does not affect the
presentation duration. In the following example, the transition effect takes
three seconds to complete:
<transition id="fade1" type="fade" subtype="crossfade" |
To use the same transition type but vary the transition speeds, define the transition multiple times, each time with a different ID and duration. For example, the following tags define the same transition type and subtype, but the first effect lasts two seconds whereas the second effect lasts four seconds:
<transition |
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For More Information:
The dur attribute uses the standard SMIL
timing values, which are described in "Specifying Time
Values".
|
Using direction="reverse"
, you can change the direction a transition effect runs.
For example, the following transition effect reveals the clip in a four-point star
that expands outward:
<transition id="p1" type="starWipe" subtype="fourPoint"/> |
Reversing the direction creates a four-point star that contracts inward:
<transition id="p2" type="starWipe" subtype="fourPoint" |
For some transition effects, you can simply use a different subtype rather than
include the attribute direction="reverse"
. For example, this transition effect:
<transition id="p3" type="pushWipe" |
is equivalent to this transition effect:
<transition id="p4" type="pushWipe" |
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Note: Reversing the direction of a transition effect that has no specific starting or ending point, such as crossfade, has no visual effect. |
Each transition effect has a starting appearance and an ending appearance.
For example, an expanding star transition normally starts as a single point in
the center of the transition area. It ends after the star has expanded out of the
transition area. You can set a different point where a transition effect starts
with startProgress
:
<transition id="wipe1" type="pushWipe" subtype="fromLeft" |
The startProgress
attribute takes a value from 0.0 (normal starting point) to 1.0
(normal ending point). This value represents a percentage. For example,
startProgress="0.25"
means that when the transition effect starts, it appears to
be 25 percent complete already. It then flows to its end point over the course
of its specified duration.
Additionally, you can use endProgress
, which also takes a value from 0.0 to 1.0
to indicate how far the transition effect progresses before it ends. The
following example defines a keyhole-shape transition effect that ends when
the keyhole has expanded to half of its normal ending size:
<transition id="key" type=" |
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Here, you can view samples of partial transition effects. |
endProgress
, the transition effect ends in an intermediate state. You can use this to create special effects with iris wipes, for example. With other types of transition effects, though, a partially completed transition may confuse the viewer.startProgress
and endProgress
attributes in a single <transition/>
tag. When you do this, the endProgress
value must be equal to, or higher than, the startProgress
value for the transition effect to exhibit any movement.startProgress
and endProgress
attributes to the same value in a <transition/>
tag, the transition effect appears to complete instantly, regardless of its duration.![]() |
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This example demonstrates an instantaneous transition effect that uses a rectangular iris wipe to mimic an old film projector. |
fill
attribute determines whether parts of that clip remain visible at the end of the effect. Use one of the following:fill="hold"
to keep the first clip visiblefill="transition"
to make the first clip disappear after the transition completesfill="remove"
to make the first clip disappear before the transition begins![]() |
For More Information: See "Using Clip Fills with Transition Effects" for more information. |
When you repeat a transition effect, the effect appears multiple times instead of just once. For example, an expanding star transition effect normally begins in the center of the clip and expands toward the clip's edges. By repeating this effect twice horizontally and twice vertically, you make a separate star shape expand in each of the clip's quadrants, as shown in the following illustration.
You repeat a transition effect by adding the horzRepeat
or vertRepeat
attribute
to a <transition/>
tag. Each attribute takes as a value a positive integer that
defines how many times the transition effect repeats horizontally or vertically,
respectively. For example, the following transition effect defines two four-
point stars that appear side-by-side:
<transition id="starHorz" type="starWipe" subtype="fourPoint" |
To have these stars appear one on top of the other, you repeat the effect vertically:
<transition id="starVert" type="starWipe" subtype="fourPoint" |
You can combine horzRepeat
and vertRepeat
attributes in the same tag. The
following example creates a grid of nine transition effects by defining three
horizontal repetitions and three vertical repetitions:
<transition id="nineStar" type="starWipe" subtype="fourPoint" |
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Tip:
Think of these attributes as defining a table. The
horzRepeat attribute defines the number of columns, and the
vertRepeat attribute defines the number of rows.
|
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This example demonstrates repeating transition effects. |
All transition effects except fades have borders. When a clip slides over another
clip from left to right, for example, the border is the new clip's right edge. By
default, the border width is 0 (zero), meaning the border is not accentuated.
By adding a borderWidth
attribute to a <transition/>
tag, you can make the
border more apparent. This attribute takes as a value a positive integer that
sets the border's pixel width. The following example sets a two-pixel border
width:
<transition id="wipe1" type="pushWipe" subtype="fromLeft" |
By default, the border is black, but you can use any other RGB color. You can also make the border blend the clip with its background. The following section explains how to do this.
Transition effects that fade to or from a color, as well as transition effects that set border widths, can include color values, which are described in Appendix C. The following example defines a transition effect in which the clip fades to a solid red:
<transition id="redFade" type="fade" subtype="fadeToColor" |
If you define a border width as described in the preceding section, you can use
the borderColor
attribute to set the border color:
<transition id="wipe1" type="pushWipe" subtype="fromLeft" |
Alternatively, you can use borderColor="blend"
to make the border blend the
clip into its background. This typically creates a blurring effect along the
border:
<transition id="wipe1" type="pushWipe" subtype="fromLeft" |
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Tip:
When using borderColor="blend" , you typically need to set
borderWidth to 10 pixels or higher to notice the blending effect.
|
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This example demonstrates border colors and border blends. |
After you define <transition/>
tags in the SMIL file header, you assign the
transition effects to clips using transIn
and transOut
attributes in each clip
source tag. You can assign transition effects only to clip source tags, not to
<seq>
, <par>
, or <excl>
groups. Any type of clip can use a transition, but
because transitions are visual, they do not affect a clip's audio track.
The transIn
attribute makes the transition effect occur as the clip starts to
play. The transOut
attribute makes the effect occur as the clip finishes playing.
Each attribute takes as a value the ID defined in a <transition/>
tag. For
example, suppose that you define the following two transition effects:
<transition |
In the SMIL file body, you could the assign the effects to a sequence of two videos like this:
<seq> |
In the preceding example, each video fades up from a solid blue when it starts,
then fades down to solid blue when it ends. It's not necessary to use both the
transIn
and transOut
attributes for each clip, though. In the following example,
the first video starts playing without any transition. As the first clip ends and
the second clip starts, there's a fade to blue and then a fade up. When the
second clip stops playback, it disappears from the screen:
<seq> |
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Note:
A transition effect assigned with a transOut attribute
always obeys SMIL timing rules. If a video normally plays for
two minutes, but has a dur="3min" value to lengthen its active
period, the transition effect occurs after three minutes.
|
The section "Setting a Fill" explains the fill
attribute, which makes the clip
disappear or remain visible when it finishes playing. Which values you use for
fill
can also affect transition effects. The following sections explain how best to
use the fill
attribute with transition effects.
When you apply transition effects to a sequence of clips, use fill="transition"
to
keep a clip onscreen long enough for a transition to occur. The transition
value
does nothing when a transition is not applied to the clip. Suppose you want to
use a three-second radial wipe like the following to introduce each new video
in a sequence:
<transition id="fan1" type="fanWipe" subtype="top" dur="3s"/> |
You could apply this transition effect to the beginning of each clip. In a
standard sequence of clips, though, each clip disappears as soon as it stops
playing. The transition effect that introduces the next clip therefore operates
against the region's background color. To keep clips onscreen during
transitions, add fill="transition"
to each clip's source tag:
<seq> |
In this sequence, each fill="transition"
attribute keeps the clip onscreen for
three seconds (the duration of the transition effect) after the clip ends
playback, long enough for the transition effect to complete. This does not
lengthen the presentation timeline. The three seconds used for each transition
effect overlap the first three seconds that each new clip plays.
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Note:
If a clip in a sequence uses a begin value to delay its
playback, a fill="transition" value in the preceding clip freezes
that clip until the clip with the begin value starts to play and
the transition effect completes. For more on begin , see "Using a
Begin Time with a Clip".
|
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Tip:
In a long sequence of clips, add fillDefault="transition" to
the <seq> tag. You do not then need to add fill="transition" to
every clip tag. For more on fillDefault , see "Specifying a Default
Fill".
|
When you use parallel groups, a fill="transition"
, fill="remove"
or fill="freeze"
attribute in a clip source tag can affect when a transition occurs. Suppose that
you define a two-second fade to black:
<transition id="toBlack" type="fade" subType="fadeToColor" dur="2s"/> |
You next apply this transition to both an image and a video playing in parallel.
In the following example, the image clip has a fill="remove"
attribute and a 30-
second duration. The clip begins to fade out at 28 seconds into the parallel
group's timeline, disappearing much sooner than the video, which has a 154-
second duration:
<par> |
To make the image fade out only after its duration has elapsed, you would use
fill="transition"
as shown in the following example. In this case, the image
disappears 32 seconds after it begins to play:
<par> |
To make the image begin to fade out two seconds before the video finishes
playing, you would use fill="freeze"
as shown in the following example:
<par> |
The following sections illustrate how to use transition tags and attributes to create various transition effects. To see more examples, get the zipped HTML version of this guide as described in "How to Download This Guide to Your Computer", and view the Sample Files page.
One of the simplest transition effects is to fade up from or down to a color.
The following example shows a sequence of two videos. There is a two-second
fade from blue as each video starts, and a two-second fade to blue when each
video ends. Each video is centered within the video region and appears at its
normal size. A begin="2s"
value is used with each video to insert a short delay
before each transition occurs:
<smil xmlns="http://www.w3.org/2001/SMIL20/Language"> |
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Click this sample to view simple color fades. |
In a simple variation of the preceding example, the first video fades up from green when it starts to play, and the second video fades down to green when it ends. When the first video stops and the second video starts, though, the two videos crossfade into each other. Clips do not need to be the same size to crossfade into each other:
<smil xmlns="http://www.w3.org/2001/SMIL20/Language"> |
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Click this sample to watch video clips crossfade. |
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