Overlays

Overlays allow a graphic or effect to be placed on top of the video. They have no effect on audio.

Overlays can be added to any input or mixer. This is defined when creating or updating the overlay, by setting the source to e.g. input1 or mixer2. Multiple overlays can be added to each input or mixer.

Overlays can be created, updated, and deleted using the API. They can also be created at start-up using a config file.

Common properties

All types of overlays have the following properties:

Name	Can be set initially?	Can be updated??	Description	Default value (if not set)
id	No	No	ID of the overlay. Positive integer. Starts at 1 and increases by 1 for each new overlay.	n/a
uid	No	No	Unqiue ID - a string in the format 'overlayX' where X is the ID	n/a
type	Yes	No	The name of the overlay type, e.g. text.	N/A - REQUIRED
visible	Yes	Yes	Boolean. Whether the effect is visible on the video.	False
source	Yes	Yes (but only in the NULL or READY states)	The uid of the input or mixer that the overlay is overlaying. e.g. mixer1	The mixer with the lowest ID (usually mixer1)

Overlay types

Brave currently supports these overlay types:

• text
• clock
• effect

text

Shows text on the screen.

Additional properties

In addition to the common properties defined above, this overlay also has:

Name	Can be set initially?	Can be updated??	Description	Default value (if not set)
text	Yes	Yes	The text to display.	Empty string
valignment	Yes	Yes	The vertical alignment of the text. Can be top, center or bottom.	Empty string

clock

The clock overlay shows the current time, and also any other text provided in the text property. It is a useful overlay to determine if there is any delay in the video.

This overlay shares the same properties as the text overlay.

effect

The effect overlay allows a range of video transformation effects to be applied.

This overlay has one additional property - effect_name - which can be set to one of the following values:

• agingtv: AgingTV (adds age to video input using scratches and dust)
• burn: Burn (adjusts the colors in the video)
• chromium: Chromium (breaks the colors of the video)
• dicetv: DiceTV ('Dices' the screen up into many small squares)
• dilate: Dilate (copies the brightest pixel around)
• dodge: Dodge (saturates the colors in the video)
• edgetv: EdgeTV effect
• exclusion: Exclusion (exclodes the colors in the video)
• optv: OpTV (Optical art meets real-time video)
• radioactv: RadioacTV (motion-enlightment)
• revtv: RevTV (A video waveform monitor for each line of video)
• rippletv: RippleTV (ripple mark effect on the video)
• solarize: Solarize (tunable inverse in the video)
• streaktv: StreakTV (makes after images of moving objects)
• vertigotv: VertigoTV (blending effector with rotating and scaling)
• warptv: WarpTV (goo'ing of the video)

If omitted, the default is edgetv.