In-Stream vs Out-Stream Video, Explained
Under IAB Tech Lab's current guidelines, in-stream video plays before, during or after content the viewer deliberately chose, with sound on by default. Out-stream video runs in its own player inside a display placement — a banner, an in-feed unit, an interstitial — independent of any content the viewer selected. The 2023 rule change was strict enough that most open-web inventory once called in-stream reclassified as out-stream.
What this looks like in a real account
The current definitions, and why they changed
IAB Tech Lab released updated guidelines for digital in-stream video and CTV ad formats in September 2022, effective June 2023. The defining test for in-stream is now specific: the viewer must have signalled deliberate intent to watch the content the ad interrupts, and the ad must default to sound on. Out-stream covers everything else — in-banner, in-page, interstitial and in-feed video, none of which sits inside content the viewer actively chose to watch. The practical effect of the tighter definition was sweeping: by one estimate, around 99% of inventory the industry previously labelled in-stream on the open web reclassified as out-stream once the sound-on-by-default rule took effect.
The rule change matters for a media buyer, not just a taxonomy purist, because "in-stream" used to appear on a lot of inventory in RFPs and vendor decks that would no longer qualify under the current definition. A supplier still using the old, looser meaning of the term isn't necessarily being dishonest — the ground genuinely shifted under the label in 2023 — but it's worth asking which definition a given inventory description is using before assuming it means what it used to.
Where Amazon DSP's inventory falls
Amazon's streaming TV inventory — Prime Video, Fire TV Channels, Twitch's video formats, and third-party publishers reached through Amazon Publisher Direct — is in-stream under the current definition: it plays around content the viewer deliberately chose, with sound on by default. Amazon's online video (OLV), served inside the shopping and browsing experience, is more mixed — some of it sits in-stream, much of it functions closer to out-stream depending on exact placement. This is worth checking directly rather than assuming, since the label affects both the expected viewer experience and the completion-rate benchmark that's fair to hold the creative to.
The distinction gets murkier on Amazon's own OLV inventory precisely because it spans placements built at different times against different definitions of the category. A unit built years before the 2023 guidelines took effect may still technically function as it always did while now sitting on the out-stream side of a line that moved out from under it — worth confirming current classification directly with Amazon or the specific publisher rather than relying on how a placement has historically been described.
Why the label matters for a media plan
In-stream and out-stream inventory carry genuinely different viewer expectations. In-stream, sound-on-by-default video demands a creative that works from the first second with audio playing — no muted-first design assumption. Out-stream video is far more likely to be encountered muted, in a smaller player, competing with page content around it, which favors a sound-off-first creative built the way Sponsored Brands video is, muted until the viewer opts in. Building one creative asset without knowing which category it's actually running in is a common, avoidable mismatch.
Testing both openings on the same underlying creative concept, rather than assuming which one a given placement needs, is the safer default when classification is genuinely unclear — cheaper than guessing wrong and discovering it only after a flight has already run.
A worked example
A brand running the same 15-second creative across Prime Video (in-stream, sound-on) and an out-stream placement inside a third-party publisher's article page needs two different creative approaches, not one shared cut. The Prime Video version can lead with dialogue or a sound cue in the first second; the out-stream version needs to work as a silent film until a viewer opts to unmute, the same design discipline Amazon's own Sponsored Brands video format requires. Testing completion rate on both without adjusting for this difference will make the out-stream placement look artificially weak.
The pattern shows up in a related, verified way in our own DSP book. Across 27 advertisers over 31 days this summer, mobile in-app video — a largely out-stream, lower-attention format in this context — generated 48.3% of every click recorded but only 3.5% of the sales, at a $26.94 cost per acquisition against $6.83 portfolio-wide, while display units running in the same apps, on the same audiences, returned 6.29x against video's 1.46x. Format and viewing context, not audience, explained almost all of the gap.
The common mistake
The mistake is assuming every video placement inside a DSP campaign is in-stream simply because it's labelled "video." Given how sharply the 2023 IAB reclassification shifted inventory, a meaningful share of what shows up under a video line item, particularly in open-web OLV placements, is technically out-stream and needs sound-off-first creative to perform. reMKTR runs 109 live Amazon DSP advertiser seats and checks the in-stream/out-stream classification of every video supply source in a plan before finalizing creative, specifically because building one asset for both categories reliably underperforms on whichever one it wasn't designed for.
A second, more subtle mistake is assuming completion rate benchmarks transfer cleanly once a placement's classification is known. Two out-stream placements can still behave very differently from each other — an in-feed unit that takes up most of a mobile screen behaves differently than a small in-banner unit in a sidebar — so the in-stream/out-stream label is a useful first filter, not a complete description of how a specific placement will perform.
| In-stream | Out-stream | |
|---|---|---|
| Plays inside chosen content? | Yes | No — its own player in a display placement |
| Sound default | On | Typically off/muted-first |
| Examples on Amazon DSP | Prime Video, Fire TV Channels, Twitch video | Some OLV placements, in-feed/in-page video |
| Creative approach | Works with audio from second one | Must work silently until unmuted |
Which one you should actually pick
This distinction matters most for a brand running video across multiple placement types and building creative once for all of them. A brand running only Prime Video or Fire TV Channels doesn't need to think about the split at all — that inventory is consistently in-stream under current definitions, and a single sound-on creative approach is the right call throughout.
Shortlist on the job, not the feature grid. Pull your search-term report for the last 90 days and total the spend against terms that produced no orders — 33.6% on the account above. Then ask each vendor on your list what they would do about it in week one, and see who answers with a process rather than a screenshot.
Common questions
Did the 2023 IAB rule change actually reduce how much in-stream inventory exists?
It reclassified inventory rather than reducing it — by one industry estimate, around 99% of what was previously called in-stream on the open web became out-stream under the sound-on-by-default requirement, even though the underlying inventory itself didn't disappear.
Is Amazon's Sponsored Brands video in-stream or out-stream?
It runs muted, autoplaying inside Amazon's own search results and product pages — closer to the out-stream, sound-off-first creative model than to the sound-on in-stream model that applies to Prime Video and Fire TV Channels.
Should I build separate creative for in-stream and out-stream placements?
Generally yes, or at minimum adjust the opening seconds — in-stream can rely on audio immediately, out-stream needs to communicate the message silently until a viewer chooses to unmute.
Does completion rate mean the same thing for both formats?
Not exactly — out-stream units are often smaller, more easily scrolled past, and encountered in a more distracted browsing context, so a lower completion rate there isn't automatically a worse result than a higher one on in-stream, sound-on CTV.
How do I check which category a specific supply source falls into?
Ask the platform or check its own published ad specs directly rather than assuming from the placement's general reputation — the 2023 reclassification changed enough inventory that older assumptions about a specific publisher or format are worth re-verifying.
We show the method before the number.
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