Trailer Social Cutdown Specs and Deliverables

The Short Answer

For a trailer campaign, plan a small set of master cutdowns rather than one cut per platform: a vertical 9:16 set for Reels, TikTok and Shorts, a square or 4:5 set for feed, and a 16:9 set for YouTube and web. Make each in a few lengths, burn in captions, keep titles and faces inside a conservative safe area, and test each file in the platform's own upload or ad preview before the date it goes live.

This post is the production checklist. For the creative thinking, read our guide to theatrical trailer cuts for social, and for the platform strategy, how to market a film on social media.

Platform Rules That Do Not Move Much

Platforms change specs often, so we only list what we checked in the platforms' own help pages on 2026-10-17, and we tell you where to look for the rest.

• YouTube Shorts: YouTube Help says a Short is square or vertical and can be up to three minutes long. Wider formats such as 16:9 stay long-form.
• TikTok in-feed ads (non-Spark): TikTok Ads Help lists 9:16 as recommended with at least 540 by 960 pixels, 16:9 at least 960 by 540 and 1:1 at least 640 by 640. It lists .mp4, .mov, .mpeg, .3gp and .avi, a file size of 500 MB or less, a bitrate of at least 516 kbps and a duration of up to 10 minutes. These are minimums, so deliver higher resolution than that.
• TikTok captions in ads: TikTok's help page says its own ad captions use a fixed white font that you cannot style, and it does not allow clickable links, @ symbols or hashtags there. It also publishes downloadable safe zone files, with a separate file for videos that use anchors.
• Meta (Instagram and Facebook): Meta's own spec page did not load for us. Third-party guides we read recommend 9:16 at 1080 by 1920, and some quote 1440 by 2560, and their safe zone percentages disagree with each other. Treat Meta's Ads Manager placement previews as the source of truth.

A Deliverables Matrix

The lengths are a planning suggestion, not a platform rule. Ask the distributor or sales agent whether they have a required set, because many already specify one in a marketing delivery schedule.

Reframing From a 2.39:1 or 16:9 Trailer

You rarely get a vertical version by cropping. Plan three ways to reframe:

1. 1Punch in and re-position on the subject when the shot allows it, keyframing the move if the subject travels.
2. 2Stack or pad a wide shot over a blurred or branded background when the composition cannot be cropped. Keep it rare, it can look cheap.
3. 3Re-cut for vertical using alternate takes or wider coverage, and choose shots that already read in a tall frame.

Work from the highest resolution source you have. A 4K or 6K timeline gives you room to reframe without softening.

Safe Areas and Text

Every platform covers part of the frame with its own interface: the username, caption, buttons and progress bar. Because the percentages differ by source and change with app updates, use a margin that works everywhere and verify in the preview.

• Keep titles, credits, release date and captions away from the top and bottom of a vertical frame, and from the right edge where buttons sit.
• Put the call to action in the middle third of the frame, not on the bottom bar.
• Keep a clean frame at the end for the platform's own buttons.
• Test on a real phone, in both the main feed and the full-screen view.

Captions and Sound

Most social video is watched with sound off at some point, so captions are part of the deliverable, not an extra.

• Burned-in captions show on every platform and can be styled, but they cannot be turned off or translated. Make a clean version without them.
• Sidecar SRT files are useful where a platform lets you upload them. Keep them as a separate deliverable, with the same file name as the video.
• Check spelling of names and titles, and keep captions inside the safe area.
• Mix for phone speakers. Keep dialogue clear and avoid thin, quiet music tails.
• For more, see captions and subtitles for film and trailers.

Per-Platform Check Before You Send

1. 1Open the file on a phone, full screen, and look at all four edges.
2. 2Upload it as a draft or ad preview on the target platform and check the crop and the interface overlay.
3. 3Confirm the first second is a strong frame, because many platforms use it for the thumbnail.
4. 4Check the file size, bitrate and length against the current spec page.
5. 5Check that music is cleared for the placement. Music rights for paid ads differ from organic posts. This is a legal question for the rights holder.
6. 6Save a version with the exact file name, date and the platform it was approved for.

File Naming

TITLE_Trailer1_9x16_30s_Captioned_v02_2026-10-15.mp4 tells an editor or social manager everything without opening the file. Add NOCAPS for the clean version. Our project folder structure guide covers naming across the whole project.

Want a person to help?

Our entertainment marketing team cuts trailer social campaigns and builds the delivery set for you, from reframing to captions to platform checks. See our entertainment marketing work, or contact us with your trailer, your release date and the platforms you plan to use.