If you are running paid video on X (formerly Twitter), getting the specs right before you upload saves you from cropped captions, rejected files, and ads that look stretched in the feed. This Twitter video ad specs guide covers aspect ratios, resolution, file formats, duration limits, and the setup details that actually affect how your ad performs once it starts playing in someone's timeline.
Why Video Specs on X Are Worth Getting Right
X video ads sit inside a fast-scrolling, mostly mobile timeline. A video that is technically correct but visually designed like a TV commercial — centered subtitles, wide landscape framing, slow opening — tends to get scrolled past before the message lands. Getting the specs right is the baseline. Designing the first few seconds and the frame composition for a small vertical screen is what actually earns the watch.
Treat this twitter video ad specs guide as two layers: the hard technical limits (file type, size, duration) that will get your ad rejected or distorted if you ignore them, and the softer design rules (safe zones, caption placement, sound-off hooks) that determine whether people actually stop scrolling.
Twitter Video Ad Specs at a Glance
These are the general specification categories you need to plan for. Exact numeric limits on file size, bitrate, and duration are periodically updated by X, so use this table to know what to check in your Ads Manager rather than as a fixed source of truth.
| Spec | What to plan for | Why it matters |
|---|---|---|
| Aspect ratio | Vertical (9:16) or square (1:1) for feed; landscape (16:9) also accepted | Vertical and square use more screen space on mobile, where most feed scrolling happens |
| Resolution | 1080×1920 for vertical, 1080×1080 for square, 1920×1080 for landscape as common starting points | Matches standard mobile and desktop rendering without upscaling blur |
| File format | MP4 or MOV, H.264 encoding as a safe default | Most reliably accepted format across X's upload tools |
| File size | Keep well under the platform's current cap, and compress if your file is unusually large | Large files can fail to upload or take longer to process |
| Duration | Short-form video (roughly 6–15 seconds) for feed attention; longer-form up to a couple of minutes if your format supports it | Shorter cuts tend to hold attention in a scrolling feed; longer formats need a stronger narrative reason to stay |
| Captions | Burned-in captions or an uploaded caption file | Many viewers scroll with sound off, so captions carry the message |
| Thumbnail | A custom cover image that reads clearly as a still frame | The thumbnail is what people see before they decide to tap play |
Aspect Ratio and Resolution: What Actually Works on X
X supports multiple aspect ratios, but not all of them earn equal screen space. In a vertical scrolling timeline, a landscape 16:9 video gets letterboxed with empty space above and below it, while a vertical 9:16 or square 1:1 video fills more of the visible frame.
- Vertical 9:16, 1080×1920 — the strongest default for mobile-first placements. Fills the screen edge to edge and matches the format most people already expect from short video content.
- Square 1:1, 1080×1080 — a solid middle ground if you're repurposing the same creative across a feed with mixed desktop and mobile traffic.
- Landscape 16:9, 1920×1080 — still accepted, but generally the weakest performer in-feed. Reserve it for cases where the same asset is pulling double duty on a platform that favors landscape, like YouTube.
If you're already producing creative for other mobile-first channels, the safe zone and composition rules are nearly identical. Our vertical video ad specs for mobile guide covers the underlying logic of safe zones and framing that applies across X, Reels, and Shorts.
File Format, Size, and Duration Limits
Format and size limits are the part of any twitter video ad specs guide most likely to go out of date, since platforms adjust caps over time. Rather than anchoring on a specific number here, use this checklist every time you prepare a new batch of ads:
- Export as MP4 with H.264 video encoding and AAC audio — the most universally accepted combination.
- Check your current file size against the limit shown in your X Ads Manager upload screen before you queue a batch of files.
- Keep your bitrate high enough to avoid visible compression artifacts, but don't export at an unnecessarily high bitrate just to inflate quality — it only increases file size and upload time.
- Test your duration against the placement you're buying. A short, punchy cut works for most in-feed placements; longer storytelling formats need a stronger reason for someone to keep watching past the first several seconds.
- Always preview the final render on an actual phone screen, not just a desktop editor, before you publish.
If your ad gets rejected on upload, the two most common causes are an unsupported codec (often from an unusual export setting in editing software) or a file that exceeds the current size cap. Re-exporting with standard H.264/MP4 settings resolves most of these issues.
Captions, Sound, and Accessibility
Design every X video ad as if the sound is off. That doesn't mean sound doesn't matter — a voiceover and music track can add polish and clarity once someone turns audio on — but your hook, offer, and call to action should all be understandable from visuals and on-screen text alone.
- Burn captions directly into the video rather than relying solely on an uploaded caption file, since not every placement displays external captions consistently.
- Keep caption text large and positioned away from the bottom and top edges, where the platform's own UI elements (like the compose bar or engagement icons) can overlap your text.
- Use word-by-word or short-phrase captions rather than long paragraphs — they're easier to read in a couple of seconds of scroll time.
- If you do add a voiceover, keep the pacing tight; a video that leans on narration alone will lose viewers who never unmute.
Twitter Video Ad Specs by Placement Type
X offers more than one way to run video, and each has slightly different practical considerations even when the technical limits overlap.
In-feed promoted video
This is the most common placement: a video ad that appears in someone's timeline alongside organic posts. Vertical or square framing, a caption-forward design, and a short duration (think single-digit to low-teens seconds) perform best here because the ad is competing directly with regular posts for a scroll-by glance.
Website and app-install video cards
These combine a video with a headline, description, and call-to-action button. Because there's already text support built into the card layout, your video doesn't need to carry every detail — it can focus on a visual hook and let the card's headline do some of the explaining.
Pre-roll and mid-roll placements
Where available, these play before or during other video content. They tolerate slightly longer durations since the viewer has already opted into watching video, but the first couple of seconds still need to establish relevance quickly, since skip options are usually available.
Common Mistakes When Preparing Video for X
- Reusing a TV or YouTube landscape cut without reframing. Centered subjects and wide shots lose impact when letterboxed in a vertical feed.
- Putting the brand logo and call-to-action text at the very bottom edge. That's exactly where the platform's interface elements often sit.
- Starting with a slow brand intro. A scrolling audience decides whether to keep watching almost immediately — open on the hook, not the logo.
- Skipping captions because the video has a voiceover. Sound-off viewing is common enough that captions should be treated as mandatory, not optional.
- Ignoring the thumbnail. An unclear or dark first-frame thumbnail can suppress plays before the video even starts.
Many of these mistakes carry over from other paid-social channels, so if you're also running ads on Meta or TikTok, it's worth reviewing our Facebook video ad specs and aspect ratio guide and Instagram feed video ad specs guide to keep your export settings consistent across platforms.
A Simple Pre-Launch Checklist
- Export in 9:16 (or 1:1 as a backup) rather than landscape.
- Confirm resolution is at least 1080 pixels on the long edge.
- Confirm file format is MP4/MOV with H.264 encoding.
- Check current file size and duration limits in your X Ads Manager.
- Add burned-in captions and test readability on a phone screen.
- Keep key text and the logo out of the top and bottom safe zones.
- Preview the thumbnail frame and swap it if it's unclear or dark.
- Watch the full ad once with sound off and once with sound on.
How FrameNotion Helps You Produce X-Ready Video Ads Fast
Once you know the specs, the harder part is usually producing a video that's actually built for a fast-scrolling, sound-off feed — not just resized from an existing asset. FrameNotion was built for that gap. Paste a product or website link, and FrameNotion AI reads the page and writes a custom 30-second vertical ad from scratch, covering hook, problem, benefit, proof, offer, and call to action — no templates.
Every ad renders natively at 1080×1920 (9:16), with an AI voiceover, a beat-synced music track, sound effects, and word-by-word captions baked in — so it's already designed to work on mute, which matters for a timeline where plenty of people scroll with sound off. Each finished ad also comes bundled as 4:5, 1:1, and 16:9, so you can match whichever placement or aspect ratio a given X campaign calls for without re-exporting from scratch.
You can upload your logo, up to six product images, and notes like a promo code, and a finished ad is typically ready in about 10 to 20 minutes. If you want to try a different opening line or headline, the AI can take change requests and generate A/B hook variants on the Pro and Agency plans. Browse example ads to see the range of styles it produces, or check pricing for current plans.
Keep in mind FrameNotion doesn't publish directly to X Ads Manager or report on ad performance — it focuses on producing the finished MP4 fast, and you handle the upload and campaign setup on the platform side.
FAQ
Frequently asked questions
What is the best aspect ratio for a Twitter (X) video ad?+
Vertical 9:16 is generally the strongest choice for in-feed placements because it fills more of a mobile screen than a letterboxed landscape video. Square 1:1 is a reasonable alternative if the same asset needs to work across mixed desktop and mobile traffic.
How long should a video ad on X be?+
For in-feed placements, shorter cuts — roughly six to fifteen seconds — tend to hold attention better in a fast-scrolling timeline. Longer formats can work for pre-roll or storytelling-driven campaigns, but they need a strong hook to earn the extra watch time.
Does X support captions on video ads?+
Yes, and because a meaningful share of feed viewing happens with sound off, burning captions directly into the video is safer than relying only on an uploaded caption file, which may not display consistently across every placement.
Can I reuse the same video ad across X, Meta, and TikTok?+
You can, as long as it's exported in a mobile-friendly vertical or square aspect ratio with captions and a fast opening hook. Each platform has its own file size and duration limits, so double-check those before uploading the same asset to a new placement.
Why was my video ad rejected on upload to X?+
The most common causes are an unsupported codec from an unusual export setting, or a file size that exceeds the platform's current cap. Re-exporting as a standard MP4 with H.264 video and AAC audio resolves most rejection issues.