Caption Burn-In - Content Management

Caption Burn-In

Render caption text permanently into the video frame. Useful for social media distribution where players may not support subtitle tracks.

KalturaRenderCaptionAttributes

Parameter	Type	Description
objectType	string	KalturaRenderCaptionAttributes
captionAssetId	string	ID of the captionAsset to burn in (required)
fontSize	int	Font size in pixels
fontColor	string	Text color in ASS format: &HBBGGRR&
fontName	string	Font family name
positionX	int	Horizontal position (pixels from left)
positionY	int	Vertical position (pixels from top)
borderStyle	int	1=OUTLINE, 3=OPAQUE_BOX
borderColor	string	Border/box color in ASS format
bold	int	Bold weight (0=normal, 1=bold)
italic	int	Italic (0=normal, 1=italic)

ASS Color Format

Colors use &HBBGGRR& (hex, blue-green-red reversed from RGB):

Color	ASS Value
White	&H00FFFFFF&
Black	&H00000000&
Yellow	&H0000FFFF&
Red	&H000000FF&

Burn-In Example

curl -X POST "$KALTURA_SERVICE_URL/service/media/action/addContent" \
  -d "ks=$KALTURA_KS" \
  -d "format=1" \
  -d "entryId=$KALTURA_ENTRY_ID" \
  -d "resource[objectType]=KalturaOperationResource" \
  -d "resource[resource][objectType]=KalturaEntryResource" \
  -d "resource[resource][entryId]=$KALTURA_SOURCE_ENTRY_ID" \
  -d "resource[resource][flavorParamsId]=0" \
  -d "resource[operationAttributes][0][objectType]=KalturaClipAttributes" \
  -d "resource[operationAttributes][0][offset]=0" \
  -d "resource[operationAttributes][0][duration]=60000" \
  -d "resource[operationAttributes][0][captionAttributes][objectType]=KalturaRenderCaptionAttributes" \
  -d "resource[operationAttributes][0][captionAttributes][captionAssetId]=$KALTURA_CAPTION_ASSET_ID" \
  -d "resource[operationAttributes][0][captionAttributes][fontSize]=24" \
  -d "resource[operationAttributes][0][captionAttributes][fontColor]=&H00FFFFFF&" \
  -d "resource[operationAttributes][0][captionAttributes][borderStyle]=1" \
  -d "resource[operationAttributes][0][captionAttributes][borderColor]=&H00000000&"