Previewing Effects and Transitions
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
[This API is not supported and may be altered or unavailable in the future.]
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.
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