Features
Compose is a full video editor in one JSON request, at a fraction of what most JSON video APIs charge. Here is everything a timeline can do, each with the JSON field that does it. Hover a preview to play the real render.
117 features · 80 rendered previews · 322 more filters by name · $0.04/min, every feature included
How a video is put together: layers, scenes and timing.
Stack clips in layers. The first track is the bottom of the picture.
timeline.tracksWrite the video scene by scene, each with its own clips and a transition into it.
timeline.scenesPut a logo or a watermark over every scene, however the video is cut.
timeline.overlaysGroup layers into one clip that moves, scales and fades as one, up to three levels deep.
"type": "composition"Leave the timing out and clips play end to end at their own length. A music bed can run to the end.
start, length: "end"Two clips that overlap with no transition between them dissolve into each other.
overlapping clipsAny colour behind the picture, or transparent for png and webm output.
timeline.backgroundGrade or treat a whole track or the final picture and mix, not one clip at a time.
track.effects, timeline.effectsRun an effect for a stretch of the clip, in seconds or percent.
effect.start, effect.lengthThe footage, stills, sound and animation a timeline is built from.
Footage by URL, with its own sound and volume.
"type": "video"Stills by URL, which take motion from keyframes like any clip.
"type": "image"Music, voice-over and sound effects, mixed with everything else.
"type": "audio"Lottie files from LottieFiles or After Effects, drawn with their transparency.
"type": "animation"Use part of a source, from one second to another.
asset.trimSlow motion or fast forward. The sound's pitch follows the speed.
speedSee-through clips, or fades in and out with keyframes.
opacityBlend a clip into what is under it, the way light leaks and textures are laid on in an editor.
blendModeTitles that stay readable and arrive with intent.
Titles and labels set in any size, weight and colour, with italic and alpha.
"type": "text"Any Google font by name, a bundled family, or your own TTF, OTF or WOFF files.
style.font, inputs.fontsArabic, Devanagari and other scripts shape correctly through bundled fallbacks, with no font file uploaded.
style.fontAn outline round the letters, so white text survives a bright picture.
style.strokeA soft shadow behind the text for depth and readability.
style.shadowA solid box behind the text, the look of a caption.
style.backgroundWhich edge of the text sits on its position: left, centre or right.
style.alignBring a title in rather than cutting it on.
style.animate.typeSplit a title so it arrives a letter, word or line at a time, in the order you choose.
animate.by, stagger, orderTake a title away the way it came in, instead of cutting it off with the clip.
style.animate.outWords timed to the picture, and clocks that count.
Every caption of a video in one clip, timed to the words and styled once.
"type": "subtitles"Load an existing .srt or .vtt file instead of writing the cues out.
subtitles.srcShow each line at once, or type it out word by word.
subtitles.revealA countdown or a stopwatch over the clip, styled like any text.
"type": "timer"Cards, bars, badges and icons, drawn by the engine with no file.
Draw rectangles, circles and more as clips.
"type": "shape"Two colours instead of one, running vertically, horizontally, diagonally or out from the centre.
shape.gradientAn outline with a real hole, so the footage shows through.
shape.strokeSquare through to fully round, which on a wide box is a pill.
shape.radiusFeather a shape's edge, the way a spotlight or a vignette is made.
shape.softnessLift a card or a bar off the footage behind it.
shape.shadowPaste path data from a design tool and draw it as a clip.
shape.path, viewBoxA bar on one track and the words on another, so each is styled and timed on its own.
shape + textKeyframe a shape's width and it becomes a progress bar.
transform.size keyframesWhere a clip sits, how big it is and what part of it shows.
Put a clip anywhere, in pixels or percent of the frame.
transform.positionDraw a clip at any size, from full frame down to picture in picture.
transform.scaleTurn a clip by any number of degrees.
transform.rotateChoose whether a position points at the clip's middle or its top-left corner.
transform.anchorGive a clip its own box, which the picture then fills.
transform.sizeHow a picture fills a box of another shape: letterboxed, cropped, stretched, or over a blurred copy of itself.
transform.fitTrim the edges of a source to punch in on the subject.
cropRound the corners of a clip, so a small one reads as a card.
crop.radiusMirror a clip left to right or top to bottom.
flipPin a clip's four corners onto a screen or a sign in the shot.
transform.cornersBuild 9:16 video with titles clear of the buttons a platform draws over it.
output.size: "shorts"Anything that changes over a clip.
Animate position, scale, rotation, opacity, size, colour and more, by time or by percent of the clip.
[{ time, value, easing }]33 motion curves, from linear to bounce and elastic.
keyframe.easingSwing a clip in around either axis, with as much depth as you choose.
rotateX, rotateY, perspectiveRamp a blur, a grade or a glow across a clip instead of holding one value.
effect settings as keyframesDuck the music under a voice and bring it back up.
asset.volume keyframesHow one clip or scene becomes the next.
One picture dissolves into the next.
"transition": "crossfade"Dip through black between two clips, for a chapter break.
"transition": "fade"The next clip slides in over the last.
"transition": "slide"The next clip pushes the last one out of frame.
"transition": "push"Reveal the next clip in place, along an edge or through a shape.
"transition": "wipe"Scale into the next clip.
"transition": "zoom"Cut straight from one clip to the next.
"transition": "none"Send a slide, push or wipe left, right, up or down.
transition.directionUse any greyscale image as the wipe pattern. Dark areas reveal first.
transition.mapGrade, finish, stylise and key the picture.
Remove a solid background colour (green screen). Put the keyed clip on an UPPER track, and the removed area shows the track below.
"type": "chromaKey"Grade the picture by hand. Every parameter is optional, and one left out leaves that quality unchanged.
"type": "color"A one-word look: greyscale, boost (vivid social pop), muted (desaturated, cinematic), lighten and darken (exposure), contrast, negative, sepia (brown archive tone), oldFilm (sepia with grain, dust, scratches, projector flicker and a vignette).
"type": "look"Soften the picture. 5 to 15 makes a backdrop that keeps text over it readable.
"type": "blur"Crisp up soft footage.
"type": "sharpen"Clean the grain a small sensor adds in low light. Works across neighbouring frames as well as inside each one.
"type": "denoise"Make the bright parts of the picture bloom. Best on lights against a dark frame: a city at night, a stage, a candle.
"type": "glow"A layer of film grain, so digital footage feels less clinical.
"type": "grain"Grade the picture with a 3D LUT, the .cube file a colourist or a grading app exports.
"type": "lut"Darken the corners to pull the eye to the middle of the frame.
"type": "vignette"Handheld camera energy on a steady shot. The picture is zoomed in slightly so its edges never show.
"type": "shake"Digital break-up: blocks of the picture jump sideways and the colours tear. For a beat or a scene change, so give it a short length.
"type": "glitch"Large square pixels over the whole picture.
"type": "pixelate"Flatten the picture into a few steps of each colour, like a screen print.
"type": "posterize"Pull the red and blue channels apart sideways, for a chromatic, analogue-video edge.
"type": "rgbShift"The dark horizontal lines of a CRT monitor.
"type": "scanLines"Turn the picture into a pencil drawing.
"type": "sketch"Blend the last moments of the clip together, so moving lights and people leave streaks.
"type": "trails"Blur one part of the picture and leave the rest sharp: a face, a number plate, a logo, a screen.
"type": "blurRegion"Show the clip only where an image says: white or opaque keeps it, black or clear cuts it away, grey fades it. A picture seen through a logo, or any shape you can draw.
"type": "mask"A stroke round the edge of a layer that has transparency: a keyed subject, a picture in picture, a logo. With dropShadow it is the sticker look. Does nothing on a clip that fills the frame. Text and shapes have their own stroke.
"type": "outline"A soft shadow under a layer that has transparency, so a logo, a cut-out or a picture in picture lifts off what is behind it. Does nothing on a clip that fills the frame.
"type": "dropShadow"322 more filters by name, each checked against its own settings before the render starts.
"type": "engine"Level, clean and mix the audio.
Set each clip's level, or keyframe it to duck under a voice.
asset.volumeFade music in and out without keyframes.
fadeIn, fadeOutPlace a sound left or right.
panEvery audio track plays together in one mix, which effects can treat as a whole.
tracksDraw the sound over the picture: the audiogram look. In the TIMELINE's effects it draws the final mix, which is the usual place. On a track or a clip it draws that track's or that clip's own sound.
"type": "visualizer"Three-band tone control. More bass and treble on a music bed, or less boom on a voice.
"type": "eq"Even out a voice, so quiet words and loud words sit at one level. The defaults suit speech.
"type": "compressor"Stop peaks from clipping. Add gain to make a track louder with no distortion, or leave gain at 0 as a safety net on the final mix.
"type": "limiter"Close the microphone between phrases, so room noise drops away in the pauses.
"type": "gate"Cut everything below a frequency. Wind, traffic and handling noise live under the voice.
"type": "highPass"Cut everything above a frequency. Music from the next room, or a voice on the phone.
"type": "lowPass"Bring sound to a standard loudness, riding the level as it goes. -16 suits online video and podcasts, -23 is broadcast.
"type": "loudness"Raise or lower the pitch without changing the speed.
"type": "pitch"A repeat behind the sound.
"type": "echo"Place a dry voice in a hall.
"type": "reverb"Remove steady background noise from under speech: a river, a fan, a street. Trained on voices, so keep it off music.
"type": "voiceDenoise"What comes back: format, size, frame rate and quality.
Video, an animated gif, sound alone, or a single still.
output.formatName a platform or a resolution instead of working out the pixels.
output.sizeAny width and height, for any aspect ratio.
output.resolutionUp to 1080p at 30 fps on Free, 1440p at 30 fps on Pro and 4K at 60 fps on Studio. Animated graphics render up to 1080p at 30 fps.
output.fpsTrade file size for quality in one word, or set the codec and its settings yourself.
output.qualityA see-through background in webm or png, for overlays you place elsewhere.
background: "transparent"Render a stretch of the timeline, or one frame as a poster image.
output.rangeChecking, listing and paying for a render.
Check a timeline exactly as a render would, with any problems, warnings and the price, at no cost.
POST /compose/validateEvery effect and filter with its settings, so code and agents can build from the live list.
GET /compose/effectsClaude, ChatGPT and other agents check and render timelines through the Rendobar MCP server.
validate_composeTyped timelines, validation and the effect lists from @rendobar/sdk.
compose.validate()A timeline written for an older version of the API still renders, and the response says what was upgraded.
upgradedEvery feature on this page is included, billed per second of finished video at $0.04/min, with a 15-second minimum.
$0.04/min117 features across the timeline, media, text, captions, graphics, layout, motion, transitions, picture and sound effects, and output. Every one is a field in the same JSON timeline, and 80 of them have a rendered preview here.
Give the clip an effects list and put one entry in it per effect, each with a type and only the settings you want to change. The list runs in the order you write it, and the same list works on a track or the whole timeline.
No. Compose bills one rate per minute of finished video, $0.04/min, however many features the timeline uses. Animated graphics such as kinetic titles and 3D turns render up to 1080p at 30 fps on self-serve plans.
Yes. Give the text an animate entrance with by set to letter, word or line, and add out to animate it leaving. Stagger and order set the rhythm, so a kinetic title is a few fields on one text clip.
Send it to POST /compose/validate, or call compose.validate in the SDK. It parses the timeline exactly as a render would, costs nothing, and returns any problems, the warnings and what the render will cost.
Yes. Through the Rendobar MCP server, Claude, ChatGPT and other agents read the same list of effects, check a timeline with validate_compose, and render it. Every preview here is a request an agent can copy as written.
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