Table of Contents

Class SMPTEAlphaVideoEffect

Namespace
VisioForge.Core.Types.X.VideoEffects
Assembly
VisioForge.Core.dll

Represents a SMPTE alpha transition effect that creates wipe transitions with full alpha channel support for transparency control.

public class SMPTEAlphaVideoEffect : BaseVideoEffect, IBaseVideoEffect, IVideoEditXVideoEffect

Inheritance

Implements

Inherited Members

Remarks

SDK Availability: VideoCaptureCoreX, MediaPlayerCoreX, VideoEditCoreX, Media Blocks SDK

Platforms: Windows, Linux, macOS, Android, iOS

This effect implements SMPTE transition patterns with alpha channel output, making it ideal for creating transitions with transparency. Unlike VisioForge.Core.Types.X.VideoEffects.SMPTEVideoEffect which blends two video sources directly, SMPTEAlpha generates an alpha mask based on the transition pattern, allowing for compositing workflows where the alpha channel controls transparency.

The SMPTE Alpha effect is particularly useful when:

  • Compositing: Creating transition masks for multi-layer video composition
  • Green Screen: Combining SMPTE patterns with keyed footage
  • Graphics Overlays: Revealing or concealing overlay graphics
  • Alpha-Based Effects: Using transition patterns as alpha mattes
  • Layer Blending: Controlling layer visibility with geometric patterns

The key difference from VisioForge.Core.Types.X.VideoEffects.SMPTEVideoEffect:

  • VisioForge.Core.Types.X.VideoEffects.SMPTEVideoEffect: Blends two video inputs directly (uses depth parameter)
  • VisioForge.Core.Types.X.VideoEffects.SMPTEAlphaVideoEffect: Generates alpha mask output (uses position parameter)

The effect is controlled by the VisioForge.Core.Types.X.VideoEffects.SMPTEAlphaVideoEffect.Position parameter which determines how much of the alpha mask is revealed (0.0 = fully transparent, 1.0 = fully opaque). The VisioForge.Core.Types.X.VideoEffects.SMPTEAlphaVideoEffect.Type parameter selects from 256+ standard SMPTE patterns, identical to VisioForge.Core.Types.X.VideoEffects.SMPTEVideoEffect.

This is a cross-platform effect using the smptealpha element. The output video maintains its color channels while the alpha channel is modulated by the transition pattern.

Performance: Real-time capable on all platforms. GPU-accelerated where available. Alpha channel processing has minimal performance overhead compared to standard SMPTE transitions.

Constructors

SMPTEAlphaVideoEffect(string)

Initializes a new instance of the VisioForge.Core.Types.X.VideoEffects.SMPTEAlphaVideoEffect class with specified name.

public SMPTEAlphaVideoEffect(string name = "smptealpha")

Parameters

name string

The unique name for this effect instance. Defaults to "smptealpha".

Fields

DefaultName

The default name for SMPTE alpha transition effects.

public static string DefaultName

Field Value

string

Properties

Border

Gets or sets the border width in pixels for the transition edge.

public int Border { get; set; }

Property Value

int

Remarks

A non-zero border value creates a semi-transparent transition zone between fully transparent and fully opaque areas of the alpha mask. This creates a softer, anti-aliased edge for the transition pattern. Larger values create broader, more gradual transition zones.

Invert

Gets or sets whether to invert the alpha mask direction.

public bool Invert { get; set; }

Property Value

bool

Remarks

When inverted, the areas that would become transparent become opaque and vice versa. This effectively reverses the reveal direction of the alpha mask without requiring a different transition pattern.

Position

Gets or sets the transition position controlling the progress of the alpha mask.

public double Position { get; set; }

Property Value

double

Remarks

The position parameter animates the alpha mask transition. As position increases from 0.0 to 1.0, the alpha channel changes according to the selected SMPTE pattern. This differs from VisioForge.Core.Types.X.VideoEffects.SMPTEVideoEffect.Depth which blends video sources directly - position controls transparency instead of cross-fading.

StartTime

Gets or sets the start time for the SMPTE alpha effect (VideoEditCoreX only).

public TimeSpan StartTime { get; set; }

Property Value

TimeSpan

Remarks

This property is only used in VideoEditCoreX for time-based effect control.

StopTime

Gets or sets the stop time for the SMPTE alpha effect (VideoEditCoreX only).

public TimeSpan StopTime { get; set; }

Property Value

TimeSpan

Remarks

This property is only used in VideoEditCoreX for time-based effect control.

Type

Gets or sets the SMPTE transition pattern type for the alpha mask.

public SMPTETransitionType Type { get; set; }

Property Value

SMPTETransitionType

Remarks

The transition type defines the geometric pattern used for the alpha mask. The pattern controls which areas become transparent vs opaque as the VisioForge.Core.Types.X.VideoEffects.SMPTEAlphaVideoEffect.Position value changes. See VisioForge.Core.Types.X.VideoEffects.SMPTETransitionType for the complete list of available patterns.

Methods

GenerateDescription()

Generates the description.

public string GenerateDescription()

Returns

string

A string containing the GStreamer element description for the SMPTE alpha effect.