Match the format to the viewer's clock: still slides read inside a 4-second glance, video pays only where someone stays past the 20-second ceiling, and moving text needs more than 60 frames a second. Street-facing placements get slides sized to the sidewalk; captive audiences get short clips; the worked window example shows the letter-height math.
Pick static slides or video by the viewer's clock, and by nothing else. A passer-by at a shopfront window gives you seconds; a queue gives you minutes. This page gives the three thresholds that turn those seconds into a format decision, the side-by-side costs, and a worked window example with the letter-height math shown.
The answer: three thresholds decide
4 seconds. The working attention span at a shopfront window, and the first 2 seconds decide only whether the eye stops. A message that needs longer than that belongs on stills with large type, or on a screen with a seated audience.
20 seconds. The ceiling for a watched clip in a public playlist, set once here and used throughout. Past that length, a standing or passing audience is gone before the payoff.
60 frames a second. What moving text needs on a larger screen. Below that, a crawl judders and the words smear.
The rule that follows: expected dwell under the ceiling, build slides. Expected dwell longer than the clip, and motion carries the message, shoot the clip at or under that length, and keep text out of the moving part unless the pipeline sustains more than 60 frames a second. Letter height follows viewing distance in both cases; the screen size and viewing distance guide carries the full sizing table.
Side by side
| Static slides | Video | |
|---|---|---|
| Attention it needs | Readable inside a 4-second glance | Worthwhile only past 20 seconds of dwell |
| Shows best | Prices, menus, hours, announcements, offers | Product in use, demonstration, atmosphere |
| Making one | A layout per message from one template | Script, shoot, edit; workload grows steeply |
| Weight per update | A few hundred KB per slide | About 20 MB per clip at 8 Mbps for a ceiling-length clip (illustrative) |
| Playback risk | A still renders the same on every pass | Judder or soft focus reads as amateur |
| Wins when | Dwell is short, content changes daily or quarterly | The viewer is captive and motion carries the message |
Where static slides win
Slides take most real placements. Street-facing retail lives on the glance, so run one message per slide, sized for the sidewalk; the retail screens section collects those placements. Menu boards are a slides job when prices sit in a few zones: four price zones updated quarterly is a common pattern in coffee shops and fast food, and that cadence is a file swap, not a project. The menu board section shows the placements. Event and agenda boards change by the hour; a speaker or time change is a replaced image, where print means a reprint run. Internal boards and sponsor logos run on slides because they are predictable and cheap to manage across many screens.
Slides go stale quietly. Set a refresh rhythm and keep the loop short; how often to update content on a small screen gives the schedule.
Where video earns its slot
Captive audiences first: waiting rooms, service queues, trade-show stands. There, dwell is longer than any clip you would run, so production quality pays. Video also wins when motion carries what a still cannot show: a product in use, a demonstration, the feel of a place.
Motion earns eyes. One display maker's published figure claims a digital sign draws 400% more views than a printed board; views are the easy part, and the clock decides whether an eye becomes a read message. Live data is a third format, separate from video: departure times, bookings, queue numbers and KPI boards earn their slot when the information changes on its own during the day. A trade-show stand is the placement where live screens lead and slides carry the sponsor logos.
Weight is the hidden cost. A still slide is a few hundred kilobytes; a ceiling-length Full HD clip at a common 8 Mbps encode is about 20 MB (8 Mbit/s x 20 s ÷ 8 bits per byte = 20 MB, illustrative numbers), and every update sends the clip again. Production workload rises faster still, and a clip that judders or looks soft costs more credibility than no clip at all. If the video you imagine is stills with motion applied, exporting slides to video for an offline player gets there for a fraction of the effort.
Moving text: the 60 frame rule
A crawl, ticker or animated headline is where video most often fails. Larger screens need over 60 frames a second for moving text to hold its shape; below that the motion judders and readability drops with every frame, and signage pipelines support high frame rates poorly. The fix costs nothing: snap the text between positions, or run the line as timed still slides, and keep real video for motion a camera shoots, hands, products, crowds. Readability at a glance is decided by type size and contrast before format; the small screen text readability guide covers the sizing.
Worked example: a shop window with 15 ft of sidewalk and 4 seconds of attention
The inputs, and where each comes from:
- 4 seconds of attention at a shopfront window, the working deployment average; the first 2 seconds decide whether the eye stops at all.
- 15 ft from the glass to the sidewalk, the set-back for a typical shopfront in this scenario.
- 20 ft of viewing distance per inch of capital letters for a fast read, the FHWA planning figure, with line spacing at 1.7 x capital height.
- A loop of 8 slides at 8 seconds each, the scenario's playlist.
- The 20-second clip ceiling from the answer above.
The rule in words: size the letters for the distance, then spend the attention budget. A passer-by joins the loop at a random moment, so the money message has to survive a partial view of one slide.
The arithmetic:
- Loop length: 8 slides x 8 s = 64 s.
- Offer share: 8 s ÷ 64 s = 0.125, so the offer slide is on screen one eighth of the time, and most 4-second glances miss it.
- Letter height: 15 ft ÷ 20 ft per inch = 0.75 in capitals. Line spacing: 1.7 x 0.75 in = 1.275 in, call it 1.3 in.
- Clip check: 20 s ÷ 4 s = 5, so a clip at the ceiling outlasts the entire glance five times over.
Result: one line of 0.75 in capitals with 1.3 in line spacing, and an offer that reaches the sidewalk on every pass instead of one pass in eight.
Decision: under the clip ceiling of expected attention, stills win. Run the offer as its own slide or repeat it as a header band on every slide, and keep each slide up long enough that the 2-second capture lands inside a full message. Video enters only where expected dwell reaches the clip length.
Recommendation
Recommendation: Build every street-facing playlist around static slides: one message per slide, capitals sized at viewing distance divided by 20 (0.75 in of capital for the 15 ft window above), 8 seconds or more per slide, evenly spaced, a short crossfade between slides. Add video only where the audience is captive and stays longer than any clip you would run; keep clips at or under the 20-second ceiling, and keep moving text off video unless the pipeline sustains more than 60 frames a second.
From decision to screen
If the verdict is slides, build the show in IMD Signage Studio, our free Windows app with no subscription and no account. It starts from ready-made slides, menu, offer, opening hours, welcome, and you type your words over them; Watch it plays the show with its real timings, so you can check that every message lands inside the glance. The show travels on a memory card or USB stick, where every file is read back and checked and the card is made safe to take out, or over the internet, where each screen looks for a new show every 2 minutes and the free online service takes files up to 25 MB each, so the example clip travels; anything longer goes on the card. It makes shows for IMD Signage displays running IMD Signage Player 1.1.0 or newer, and a clip the screen cannot play is converted on the computer to H.264 MP4 at most Full HD and 30 frames a second, well under a crawl's needs, which is why moving text stays on slides.
Questions
Should window video play with sound?
Assume sound is off. Street noise, muted screens and the shop next door make audio useless at a window, and players in public placements run muted by default. Cut every clip so it reads with picture and captions alone: no spoken payoff, no instructions given only in voice, and any offer stated as on-screen text.
Do transitions between slides matter?
A short crossfade is all a playlist needs; it marks the change so the loop never looks frozen. Wipes and animated transitions spend the viewer's seconds on the transition itself, and a glance that lands mid-motion sees no words at all. Keep the headline in the same place on every slide so the eye re-finds it without searching.
How many slides should a window loop run?
Short. The example loop of 8 slides at 8 seconds puts the offer on screen one eighth of the time, so most glances miss it. Halve the loop and the offer's share doubles. Two strong slides beat eight weak ones at a window; a captive room can carry more, because viewers look up again and again.
Planning information, not legal or engineering advice. Rules differ by place: check codes and permits with your local authority and your licensed trades.