Previewing Effects and Transitions

Microsoft DirectShow 9.0

Previewing Effects and Transitions

Some effects and transitions take a relatively long time to render. During preview this can cause the video to become choppy or out of sync with the audio. You can increase preview speed by disabling effects or transitions:

• To disable all effects, call IAMTimeline::EnableEffects.
• To disable all transitions, call IAMTimeline::EnableTransitions.
• To disable a particular transition, call IAMTimelineTrans::SetCutsOnly.

When effects are disabled, they are not rendered during preview. When a transition is disabled, it is rendered as a jump cut. The segue between tracks still occurs, but the visual effect is not rendered.

If an effect or transition cannot be rendered, the render engine substitutes a default effect or transition. Call the IAMTimeline::SetDefaultEffect method to set the default effect, and the IAMTimeline::SetDefaultTransition method to set the default transition. If you do not specify a default, or if the one you specify also causes an error, DES uses its own default.

• Note You can also improve preview quality by increasing the amount of frame buffering. See IAMTimelineGroup::SetOutputBuffering.