What specs does a programmatic DOOH creative need? For most screens: a JPG or PNG in RGB for static, or an MP4 at 30 fps and under 5,000 kbps for video, built at the screen's native size (usually 1920×1080 or 1080×1920) and, for video, most often 15 seconds long. Every file still has to be approved by the media owner before it plays, so the real work is matching each network's own limits and getting approval in time.
This guide is organised the way a creative actually moves from design to screen: choose the format, build the right set of files, check the file size, pass approval, then design for where the screen sits. Buying happens through a DSP, as our guide to how programmatic DOOH buying works explains, but no amount of good buying fixes a file that will not play.
Why a bought impression can still fail to play
On the open web, a creative that meets the spec usually serves without anyone looking at it. Out-of-home is different. Broadsign's June 2026 DOOH specs guide notes that media owners approve every creative before it runs, including inventory bought programmatically through open RTB, and that a file not sized to the screen's native resolution may appear cropped, letterboxed or distorted, which can lead to rejection. General DSPs add their own rules too. Google's Display & Video 360 DOOH help page, for example, supports static images and standard video only, not HTML5 or other dynamic formats, and says a creative cannot be edited after it has been assigned because that would invalidate the publisher's review.
So treat specs and approval as part of the media plan, not a step after it.
Step 1: Pick the format
| Format | Files | Key specs | Watch out for |
|---|---|---|---|
| Static | JPG, PNG | RGB colour, 72 ppi, native screen size | CMYK files exported from print artwork |
| Video | MP4 | 30 fps, bitrate under 5,000 kbps, even-numbered pixel dimensions | Network caps lower than 5,000 kbps; length must match the slot |
| HTML5 and dynamic | Self-contained HTML5 package | Set by each publisher | Not every network or DSP supports it; pre-approval usually required |
The static and video specs above are the baseline in Broadsign's guide; individual networks can be stricter, so their own sheet always wins. For HTML5, Moving Walls' June 2023 article on HTML5 and DCO in DOOH points out that the screen's content management system and media player must be able to handle HTML5 packages, and that bandwidth decides how much can be cached on the player. Check both before you design anything that depends on live data. If you plan weather or time triggers, our guide to dynamic creative optimisation covers how to set them up.
Step 2: Build the right set of files
Most programmatic spend goes to a handful of sizes. In Broadsign's 2026 programmatic report, summarised by Billboard Insider in August 2026, 1080×1920 and 1920×1080 together took 77% of programmatic video spend in 2025 on the Broadsign and Place Exchange platforms. For static display, the top three sizes were 1080×1920 (31.4%), 1400×400 (24.2%) and 1920×1080 (23.3%).
On length, Place Exchange's H1 2025 Programmatic OOH Trends Report found 15 seconds was the most common video duration, with 62% of video spend. Broadsign's guide cites OAAA durations of 8, 10, 15 and 30 seconds and notes that airport video is typically 10 seconds. Both sets of figures come from specific platforms, so check them against the networks in your own plan.
Illustrative example: counting the files
Illustrative example. The campaign below is hypothetical.
A brand plans video on landscape and portrait screens, in 15 and 10 second versions, with three weather variants (sunny, rainy, default), plus a static 1400×400 banner for each weather variant.
- Video: 2 sizes × 2 lengths × 3 variants = 12 MP4 files.
- Static: 1 size × 3 variants = 3 PNG files.
- Total: 15 files, each needing approval from every media owner in the buy.
Write this matrix down before design starts. It shows the real workload, and it makes it obvious when one extra variant multiplies the number of files to build and approve.
Step 3: Check the file size before you export
Video file size follows directly from bitrate and length: size in megabytes is roughly bitrate in kilobits per second × seconds ÷ 8,000.
Illustrative example. The network limit below is hypothetical.
- A 15 second video at 5,000 kbps: 5,000 × 15 ÷ 8,000 ≈ 9.4 MB.
- The same video at 30 seconds: 5,000 × 30 ÷ 8,000 ≈ 18.8 MB.
- If a network caps files at 10 MB, the 15 second version fits, but the 30 second version needs a bitrate of about 2,600 kbps or less (10 × 8,000 ÷ 30 ≈ 2,667).
Real files carry a little extra for audio tracks and container data, so leave some headroom. Broadsign's guide says file size limits vary by publisher, which is why the network's own number, not an agency default, should set the export settings.
Step 4: Plan for approval
- Submit early. Approval is manual at many media owners, so allow time before the flight starts, and more for HTML5.
- Lock the creative. Edits after assignment can restart review, as the Display & Video 360 rules show.
- Check category rules. Broadsign's guide notes that sensitive categories such as alcohol, cannabis and political messaging may face extra restrictions that vary by market, venue and media owner.
- Keep a rejection log. Record each rejection reason by network so the next campaign avoids it.
Step 5: Design for the place, not just the pixels
Meeting the spec gets a file approved. Whether anyone takes in the message depends on where the screen is and how long people look at it.
| Setting | Viewing time | What works |
|---|---|---|
| Roadside | A few seconds or less | One idea, a short headline, strong contrast, no QR code |
| Busy street | Short, with a lot competing for attention | A clear subject and colours that stand out from the surroundings |
| Mall escalator or transit platform | Longer, with people moving slowly or waiting | Room for an offer, directions or a QR code |
| Elevator | About 20 to 30 seconds, viewed close up | Smaller type and a longer story; low resolution shows |
The roadside guidance draws on Moving Walls' January 2026 article on the six-second rule, which cites an OAAA viewing window of 3 to 7 seconds and recommends a headline of 7 words or fewer. The venue rows follow its companion piece on how one ad looks across five screen types. A simple test that suits any setting: view the design at a small size from across the room, and if the message does not land in a couple of seconds, cut words.
The audience matters as much as the setting. Our guide to reaching Gen Z and Millennials looks at choosing the moments and places where a younger audience will actually see the screen.
A pre-flight checklist
- Every network and the DSP support the format you built.
- Static files are JPG or PNG in RGB at the screen's native size.
- Video is MP4, 30 fps, even-numbered dimensions, within each network's bitrate and file size limits.
- Video lengths match the slot lengths in the buy.
- HTML5 units have publisher pre-approval and have been tested with live or sample data.
- The file matrix is complete: every size, length and variant exists.
- Creatives are final before assignment, and submitted with time for review.
- The message reads at a glance for the setting it will run in.
Spec problems are one of the avoidable causes covered in common programmatic DOOH campaign mistakes. When choosing a platform, creative format support belongs on the scorecard in our guide to choosing a DSP for programmatic DOOH. For creative that ran and published its results, see seven real programmatic DOOH campaigns, and to judge your own, our guide to measuring pDOOH success.