Event promo video: make one with AI from your poster

An event promo video is a short clip that sets the mood and puts the facts people act on, the event's name, date, venue, and ticket link, on screen long enough to read. Build it from what you already have, such as the poster art or venue photos, and cut a vertical 9:16 version for Stories and Reels plus a 16:9 version for YouTube and screens at the venue.

With Sume, animate the poster art as the first frame of short clips, join them over a music bed on Timeline 1.0, and burn the event details as timed caption cues. Platform rules are quoted from Meta's ads guide pages for Instagram Reels and Instagram Stories and YouTube's Video resolution & aspect ratios, which calls 16:9 its standard on a computer. Sume facts come from the Video generation, Timeline 1.0, Music Router, and Video captions docs and the Sume API reference, read on 2026-09-28. Anything called current code is read from Sume's source.

How long should an event promo video be?

There's no single right length; each placement publishes its own rules. Meta's ads guide lists 9:16 for Instagram Reels and Stories ads, and says Stories plays a video ad under 16 seconds in full but may split a longer one into cards. How long should an ad be? compares other platforms. On Sume, a cut of 60 seconds or less keeps the text step to one caption job, because in current code a caption job refuses longer sources.

How do I make an event promo video with AI?

Each step is one Sume call:

How do I animate the poster?

Use the poster art without its text as the first frame, and put the words back in the caption step, so the date and venue come from your text, not the model. Send the image at a public HTTPS URL in frame_images with frame_type: "first_frame", pick 9:16 or 16:9, and describe one motion: stage lights sweeping, confetti drifting, the camera pushing in. On models that take a last frame, you can also pin where the clip ends with a last_frame, such as the same text-free art.

• Use images you have the rights to, including photos of performers or speakers.
• Make a few short clips from different images; Image-to-video API covers the frame fields.

curl -X POST https://api.sume.com/v1/videos \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: gala-poster-clip-9x16-v1" \
  -d '{
    "model": "seedance-2",
    "prompt": "Warm stage lights sweep slowly across the scene while gold confetti drifts down",
    "frame_images": [
      { "type": "image_url", "image_url": { "url": "https://example.com/gala-poster-art.png" }, "frame_type": "first_frame" }
    ],
    "aspect_ratio": "9:16",
    "resolution": "720p",
    "duration": 5
  }'

How do I join the clips and add music?

Make the bed with POST /v1/music-router/generate, describing the mood and asking for the length in the prompt. Then join the clips over it in one Timeline 1.0 render per shape: each clip in a slot, the track as soundtrack at gain_db 0, and audio.mode: "silence" with the promo's length. Real estate listing video from photos shows the full request.

• The default frame is 1080×1920; set output to 1920×1080 for the 16:9 cut. A clip of the other shape is placed by its slot's fit: cover (the default), contain, stretch, or blur.
• In current code the clips' own audio isn't used; the bed is the only sound.

How do I put the date, venue, and ticket link on screen?

Burn them onto each finished cut with POST /v1/video-captions, one cue per line: the event name, then the date and venue, then where to get tickets, each held long enough to read. Cues skip speech-to-text, so the words and times are yours, and the music bed gives the cut the audio stream the caption job needs in current code. With no style, Latin text gets slam, which in current code prints it in capitals and lightly tints the whole frame; proofread the render.

• Meta's guide suggests keeping roughly the top 14%, the bottom 35%, and 6% on each side of a 9:16 ad free of text and logos. design.placement.anchor_ratio sets the line's center as a fraction of the frame's height; 0.45 keeps it between the top and bottom margins.
• Keep an uncaptioned copy of each cut. If the date or venue changes, rerun only the caption job.

curl -X POST https://api.sume.com/v1/video-captions \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: gala-details-9x16-v1" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/gala-promo-9x16.mp4",
    "design": { "placement": { "anchor_ratio": 0.45 } },
    "cues": [
      { "text": "Riverside Spring Gala", "start": 0.5, "end": 4 },
      { "text": "May 16 · 7 PM · Riverside Hall", "start": 4.5, "end": 10 },
      { "text": "Tickets at example.com/gala", "start": 10.5, "end": 15 }
    ]
  }'

What does an event promo video cost?

Each clip is reserved at its model's provider list price × 1.25. A music track is $0.125 per audio. Timeline is listed at $0.10 per output minute and reserves whole minutes, so a 15-second cut reserves one. Each is plus a 5.5% agent fee by default. A caption job is a fixed amount per cut of up to 60 seconds, listed on the Video captions page.