scale_caption_sizeMake the captions bigger or smaller by a multiplier.
Argument
Type
Description
factorrequired
number
1.25 = 25% bigger, 0.8 = smaller.
style_id
string
Caption style id (omit to change every caption style).
set_captions_enabledTurn the captions on or off.
Argument
Type
Description
enabledrequired
boolean
On or off.
set_caption_textFix the wording of one caption.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
textrequired
string
The corrected caption line.
apply_caption_override_to_allGive every caption the same position and size tweak (after nudging one into place).
Argument
Type
Description
caption_x
number
Horizontal centre in video pixels.
caption_y
number
Top edge in video pixels.
caption_scale
number
Multiplier on the style's font size.
caption_max_width
number
Text box width cap, in video pixels.
except_item_id
string
Caption to leave alone — usually the one already positioned.
Graphics
The overlay cards — their copy, their theme and how they display.
set_graphic_contentFix or reword the text inside a graphic.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
contentrequired
object
Field → new value, e.g. {"quote": "…", "speaker": "…"} or {"value": "58%", "label": "of readers"}.
set_graphics_themeChange the brand look of every graphic — colours, corners, font, animation speed.
Argument
Type
Description
brand_name
string
primary_color
string
secondary_color
string
accent_color
string
background_color
string
Background colour (hex), or null to clear it.
text_color
string
font_family
string
Font family name.
corner_style
string
One of: sharp, rounded, pill.
shadow_preset
string
One of: none, subtle, medium, bold.
animation_speed
string
One of: fast, normal, slow.
set_graphic_codeLand revised Remotion code for a dynamic graphic.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
tsx_coderequired
string
The revised Remotion TSX, as returned by the graphic-revision capability.
editable_props
array
Editable-prop descriptors that came back with the code.
set_graphic_displayChange how a graphic is presented — overlay or full-screen takeover, where it sits, its takeover backdrop.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
display_mode
string
One of: takeover, overlay, speaker_pip.
graphic_position
string
One of: center, lower_third, upper_third, full_screen.
takeover_background_color
string
Backdrop colour (hex) behind a takeover graphic.
box_x
number
Graphic box left edge, in video pixels.
box_y
number
Graphic box top edge, in video pixels.
box_width
number
Graphic box width, in video pixels.
box_height
number
Graphic box height, in video pixels.
Assets
The registry of files a video draws on.
add_assetRegister a file (a clip, image, or audio track) so it can be placed on the timeline.
Argument
Type
Description
urlrequired
string
Absolute http(s) URL of the file.
asset_type
string
Media type of the file. One of: video, audio, image.
asset_id
string
Asset id (e.g. broll_001), from the edit state — not an item id.
width
number
Width in pixels.
height
number
Height in pixels.
duration_seconds
number
Length of the source file in seconds.
replace_assetSwap the file behind an existing asset, keeping every placement that references it.
Argument
Type
Description
asset_idrequired
string
Asset id (e.g. broll_001), from the edit state — not an item id.
urlrequired
string
Absolute http(s) URL of the file.
asset_type
string
Media type of the file. One of: video, audio, image.
width
number
Width in pixels.
height
number
Height in pixels.
duration_seconds
number
Length of the source file in seconds.
set_asset_metaCorrect an asset's dimensions or duration (e.g. after probing the real file).
Argument
Type
Description
asset_idrequired
string
Asset id (e.g. broll_001), from the edit state — not an item id.
width
number
Width in pixels.
height
number
Height in pixels.
duration_seconds
number
Length of the source file in seconds.
Tracks
Whole lanes — mute one, change its level, add or remove it.
set_track_enabledTurn a whole lane on or off (e.g. drop the music or the b-roll).
Argument
Type
Description
enabledrequired
boolean
On or off.
track_id
string
Track id, when addressing one specific lane.
role
string
Lane role — the usual way to address a lane. One of: main, broll, graphics, branding, narration, voiceover, bgm, sfx, primary, translation, color, blur, lut, curves.
track_type
string
Address every track of a type. One of: visual, audio, captions, effects.
set_track_volumeSet the level of a whole audio lane.
Argument
Type
Description
volumerequired
number
0 = silent, 1 = unchanged, up to 2.
track_id
string
Track id, when addressing one specific lane.
role
string
Lane role — the usual way to address a lane. One of: main, broll, graphics, branding, narration, voiceover, bgm, sfx, primary, translation, color, blur, lut, curves.
track_type
string
Address every track of a type. One of: visual, audio, captions, effects.
set_track_soloSolo an audio lane in the mix.
Argument
Type
Description
solorequired
boolean
Solo an audio lane. Not exclusive — several can be soloed at once.
track_id
string
Track id, when addressing one specific lane.
role
string
Lane role — the usual way to address a lane. One of: main, broll, graphics, branding, narration, voiceover, bgm, sfx, primary, translation, color, blur, lut, curves.
track_type
string
Address every track of a type. One of: visual, audio, captions, effects.
add_trackAdd an empty lane.
Argument
Type
Description
track_typerequired
string
Address every track of a type. One of: visual, audio, captions, effects.
rolerequired
string
Lane role — the usual way to address a lane. One of: main, broll, graphics, branding, narration, voiceover, bgm, sfx, primary, translation, color, blur, lut, curves.
name
string
User-facing lane label, e.g. "B-roll 2".
remove_trackDelete a lane and everything on it.
Argument
Type
Description
track_idrequired
string
Track id, when addressing one specific lane.
rename_trackRelabel a lane.
Argument
Type
Description
track_idrequired
string
Track id, when addressing one specific lane.
namerequired
string
User-facing lane label, e.g. "B-roll 2".
Transitions
How one shot becomes the next.
set_transitionsRestyle the transitions already in the cut.
Argument
Type
Description
kindrequired
string
"cut" removes the effect. One of: cut, crossfade, fade_through_black, whip_pan, zoom_punch, smooth_zoom, slide, wipe, clock_wipe, flip, glitch, light_leak, film_burn.
transition_seconds
number
How long each transition runs.
track_id
string
Track id, when addressing one specific lane.
set_item_transitionSet the transition on one item — how it enters, how it leaves, or a cut between two.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
slot
string
Which end of the item. Ignored when pair_item_id is given (that is always out→in). One of: in, out, both.
pair_item_id
string
The item on the other side of a cut. Given, the same transition is written to this item's `out` and that item's `in`.
kind
string
"cut" removes the effect. One of: cut, crossfade, fade_through_black, whip_pan, zoom_punch, smooth_zoom, slide, wipe, clock_wipe, flip, glitch, light_leak, film_burn.
transition_seconds
number
How long each transition runs.
transition_direction
string
One of: left, right, up, down.
transition_easing
string
One of: linear, ease-in, ease-out, ease-in-out, spring.
transition_intensity
number
0 subtle → 1 strong.
remove_transitionTurn a transition back into a hard cut.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
slot
string
Which end of the item. Ignored when pair_item_id is given (that is always out→in). One of: in, out, both.
pair_item_id
string
The item on the other side of a cut. Given, the same transition is written to this item's `out` and that item's `in`.
Items
Individual clips on the timeline — their timing, source and levels.
add_itemPlace a registered asset on the timeline — b-roll, a logo, a music bed, or a sound effect.
Argument
Type
Description
asset_idrequired
string
Asset id (e.g. broll_001), from the edit state — not an item id.
start_secondsrequired
number
Start time on the finished video's timeline.
end_secondsrequired
number
End time on the finished video's timeline.
source_start_seconds
number
Where to start inside the source file. Vary it per placement so one long clip yields different shots.
role
string
Lane role — the usual way to address a lane. One of: main, broll, graphics, branding, narration, voiceover, bgm, sfx, primary, translation, color, blur, lut, curves.
track_id
string
Track id, when addressing one specific lane.
volume
number
0 = silent, 1 = unchanged, up to 2.
description
string
Short note about what the shot shows.
item_id
string
Timeline item id (e.g. broll_item_001), from the edit state.
remove_itemTake an item off the timeline.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
set_item_timingMove an overlay or graphic to a different moment, or change how long it holds.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
start_seconds
number
Start time on the finished video's timeline.
end_seconds
number
End time on the finished video's timeline.
set_item_sourceChoose which part of the source file an item plays (its in-point).
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
source_start_secondsrequired
number
Where to start inside the source file. Vary it per placement so one long clip yields different shots.
source_end_seconds
number
Optional out-point inside the source file.
set_item_volumeChange how loud one item is.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
volumerequired
number
0 = silent, 1 = unchanged, up to 2.
set_item_fadeFade an item's audio in or out.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
fade_in_seconds
number
Seconds to ramp up from silence.
fade_out_seconds
number
Seconds to ramp down to silence.
set_item_dataUpdate an item's descriptive payload — a music bed's title/artist/loop, a shot's description.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
datarequired
object
Field → new value, merged over the existing payload. e.g. {"title": "Hype Bed", "artist": "", "provider": "elevenlabs", "loop": true}.
set_item_transformMove or resize a visual item on screen (its box, not its timing).
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
x
number
Left edge in video pixels.
y
number
Top edge in video pixels.
w
number
Box width in video pixels.
h
number
Box height in video pixels.
move_itemMove an item to a different moment on its own lane.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
start_secondsrequired
number
Start time on the finished video's timeline.
ripple
boolean
Also slide the items after it, closing the gap left behind and opening one at the destination. Off by default; needs an explicit target.
duplicate_itemCopy an item, placing the copy immediately after it.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.
start_seconds
number
Start time on the finished video's timeline.
split_itemCut an item in two at a given moment.
Argument
Type
Description
item_idrequired
string
Timeline item id (e.g. broll_item_001), from the edit state.