Online video, abbreviated OLV, is video advertising served on websites and mobile apps run by publishers, outside connected television (CTV) screens and outside the feeds of social platforms. The advertisement plays inside a player the publisher controls, either before or during a clip the viewer chose, or in a unit embedded in an article or an app screen. The label exists because video budgets are now planned in three buckets, and buyers need a name for the one that is neither the living-room television nor Instagram, TikTok or YouTube.

The Interactive Advertising Bureau (IAB) supplies the working definition. Its 2026 Digital Video Ad Spend & Strategy Report, published in full in July, describes online video as short-form video from web and app-based publishers, and sets it beside CTV and social video, which in the US IAB taxonomy includes YouTube. That three-way split is now the frame most trade figures use.

How an OLV impression is bought

The chain starts with a player. A publisher embeds one from a vendor such as JWX, formerly JW Player, or builds its own, and connects it to an ad server through a VAST tag or through Google's Interactive Media Ads (IMA) software development kit. When a break or slot comes up, the player calls the ad server, which may run a header bidding auction through Prebid or pass the opportunity to supply-side platforms (SSPs).

Each SSP turns the opportunity into an OpenRTB bid request carrying a video object. That object tells demand-side platforms (DSPs) such as Display & Video 360 (DV360), The Trade Desk or Amazon DSP what the player can handle. The mimes field lists accepted file types, minduration and maxduration bound the length in seconds, protocols enumerates supported VAST versions, and w and h give the player size in pixels. The startdelay field places the advertisement in time: 0 for pre-roll, -1 for a generic mid-roll, -2 for post-roll. Playbackmethod records how play begins, separating autoplay with sound (1), muted autoplay (2), click to play (3) and playback on entering the viewport with sound (5) or without it (6).

The field carrying most commercial weight is plcmt. IAB Tech Lab introduced it in the OpenRTB 2.6-202303 release in March 2023, replacing the older placement field, with four values: instream (1), accompanying content (2), interstitial (3) and no content or standalone (4). IAB Tech Lab clarified the conditions on February 4, 2025: a placement is instream only if sound is on by default or the viewer has shown clear intent to watch, and the video is the focus of the visit. Sources whose signals cannot be verified risk having every placement treated as accompanying content.

The winning DSP returns VAST markup, the Video Ad Serving Template telling the player which file to fetch and which events to report. The player then fires impression, quartile and completion beacons, while a verification script running through the Open Measurement software development kit reports viewability. Under the Media Rating Council (MRC) standard set in August 2015, a video impression is viewable when 50% of its pixels are in view for two continuous seconds.

A worked example shows how the fields separate inventory on one news site. A reader clicks a clip on a dedicated video page: the request carries plcmt 1, startdelay 0 and playbackmethod 3. Further down an article, a player showing editorial clips starts muted as it scrolls into view: plcmt 2, playbackmethod 6. A unit playing nothing but advertisements between paragraphs sends plcmt 4. All three are OLV. They are not priced alike.

Pricing follows the signal. Instream inventory usually trades on cost per thousand impressions (CPM), often through private marketplace deals. Outstream units are more often sold on cost per completed view (CPCV) or viewable CPM. Teads, which built its business on outstream, extended both models to publishers in August 2023.

Origin and evolution

The phrase predates the acronym. Pre-roll on publisher sites ran on incompatible player and ad server integrations until the IAB released VAST for public comment on July 29, 2008, giving the industry a shared XML format. YouTube launched TrueView skippable advertisements on December 1, 2010, and the MRC viewability guideline for video followed five years later.

Two shifts then reshaped the category. Browsers turned against sound: Chrome's autoplay policy, in force from April 2018, allows muted autoplay everywhere but sound only after user interaction or, on desktop, when a site's Media Engagement Index is high enough. Much publisher video became silent by default, and outstream units multiplied. Streaming, meanwhile, moved to the television set, and CTV became a budget line of its own. What remained on laptops and phones outside the platforms became, in practice, OLV.

Standards arrived on the back of commercial disputes. IAB Tech Lab's revised Video Ad Format guidelines and plcmt came in March 2023. Google tightened its video publisher policies from April 1, 2024, requiring AdSense, Ad Manager and AdMob publishers to declare audibility and placement type and permitting only one video to autoplay with sound at a time. A revision effective September 23, 2024 barred autoplay until at least half the unit is visible. Adform implemented the new signals on April 15, 2025, keeping the legacy field during migration.

Why the label matters

Money comes first. According to IAB estimates prepared with Guideline, US online video spending will reach $20.7 billion in 2026, up 10%, against $29.3 billion for CTV and $31.9 billion for social video, within a digital video market above $80 billion. OLV is the smallest of the three and the slowest-growing. The same report charts it at $16.6 billion in 2024 and $18.9 billion in 2025. It also funds its rivals: 36% of buyers raising CTV budgets in 2026 said the money would come from OLV excluding YouTube, according to the IAB survey of 360 buyers.

Europe counts differently. IAB Europe's AdEx Benchmark 2025 put video at 34.0 billion euros, up 19.6%, equal to 48.2% of non-social display. Programmatic video outside social rose 19.8% to 9.832 billion euros. That display video category, however, includes advertising video on demand services such as YouTube, which the US IAB files under social.

For publishers, OLV is video revenue that does not depend on a platform's auction. JWX launched a swipeable vertical player on February 19, 2026, installed with one line of JavaScript, and a Media.net survey of more than 1,000 US consumers found 75% would stay longer on sites with videos matched to their interests. Buying systems treat the category as a line item too: Mediaocean's Prisma connected to Magnite in March 2024 for CTV and OLV inventory alike.

Limitations and disputes

Classification is the core problem. Instream commands a premium, which gives sellers a reason to label muted, scrolling units as instream, a pattern that has dogged outstream for years. The Trade Desk blocked Yahoo open marketplace video inventory for some advertisers on June 17, 2024, citing IAB in-stream definitions.

Google's network faced the same charge. In June 2023, Adalytics reported that in some campaigns between 42% and 75% of TrueView in-stream spend went to Google Video Partner sites and apps that did not meet Google's standards, including muted, autoplaying outstream players. Google rejected the findings. A company blog post attributed to Marvin Renaud, its director of global video solutions, described the claims as extremely inaccurate and said the overwhelming majority of TrueView spend runs on YouTube. The factual dispute was never resolved in public.

Definitions are unstable. The US IAB puts YouTube in social video; IAB Europe's taxonomy places it in display video. The same impression can sit inside OLV in one market's statistics and outside it in another's. Muted playback raises a separate question about value: a silent completion on a phone scrolled past by a reader is not the exposure of a chosen clip watched with sound, although both fire the same beacon. Outstream also competes for the same budgets as instream and social without being either.

Not the same as

CTV. Defined by the screen rather than the publisher. A broadcaster's app on a smart television is CTV; the same broadcaster's clip on its mobile website is OLV.

Social video. Video in platform feeds, including YouTube under the US IAB taxonomy, bought mostly inside each owner's tools rather than through open bid requests.

In-stream and outstream. Placement types, not channels. Both occur within OLV, and plcmt is the field that separates them.

OTT. Over-the-top describes streaming delivery that bypasses cable or satellite. It overlaps with CTV and with some OLV, and is used loosely for both.

Recent developments

The IAB is rewriting the vocabulary. Its Redefining Media Types (RMT) Standard, released on July 9, 2026, classifies video environments across CTV, online video, social video, FAST, video podcasting and retail video by how viewers watch, with eight impression-level attributes intended for OpenRTB and AdCOM. Sources conflict on the comment deadline: the July 9 announcement gave August 8, 2026, while the IAB's standard page, as of September 2026, says August 21. A webinar on the final version is scheduled for October 15.

Supply plumbing is moving in parallel. Amazon DSP began serving VAST 4 on third-party publisher inventory in 34 markets on September 2, 2026, although Amazon's own Stores and Fire TV inventory still accepts only VAST 2 and 3 creatives. DV360's third-quarter roadmap auto-archives legacy maximum cost-per-view and Video reach 1.0 line items on October 26, 2026, and Connatix appears as JWX in its reporting from September 21, with exchange identifiers unchanged. For sellers of online video, the premium still rests on a single integer in the bid request, and on whether buyers believe it.

Timeline

  • July 29, 2008: The IAB releases the Video Ad Serving Template (VAST) for public comment
  • December 1, 2010: YouTube launches TrueView skippable in-stream advertisements
  • August 2015: The MRC sets video viewability at 50% of pixels in view for two continuous seconds
  • April 2018: Chrome's autoplay policy restricts autoplay with sound, leaving muted autoplay permitted
  • March 2023: IAB Tech Lab introduces plcmt in OpenRTB 2.6-202303 and deprecates the placement field
  • June 2023: Adalytics publishes its report on TrueView in-stream spend across Google Video Partners
  • March 2024: Mediaocean and Magnite connect Prisma to CTV and OLV inventory
  • April 1, 2024: Google's streamlined video publisher policies take effect
  • June 17, 2024: The Trade Desk blocks Yahoo open marketplace video inventory for some advertisers
  • September 23, 2024: Google moves video rules into Video inventory restrictions for AdSense publishers
  • February 4, 2025: IAB Tech Lab clarifies the four plcmt values
  • April 15, 2025: Adform SSP implements the OpenRTB 2.6 placement signals
  • February 19, 2026: JWX launches Vertical Video for publisher-owned sites
  • May 5, 2026: The IAB forecasts US online video spending of $20.7 billion for 2026
  • July 7, 2026: IAB Europe puts European video advertising at 34.0 billion euros for 2025
  • July 9, 2026: The IAB releases the Redefining Media Types Standard for public comment
  • September 2, 2026: Amazon DSP begins serving VAST 4 on third-party inventory in 34 markets
  • September 21, 2026: Connatix appears as JWX in DV360 reporting
  • October 26, 2026: DV360 auto-archives legacy maximum cost-per-view and Video reach 1.0 line items

Summary

Who. Publishers and their player vendors create OLV inventory; SSPs and ad servers package it; DSPs including DV360, The Trade Desk and Amazon DSP buy it for advertisers and agencies. IAB and IAB Tech Lab define it, the MRC sets its viewability standard, and browser makers and Google policy shape how it plays.

What. Video advertising served on publisher websites and apps, outside CTV screens and social platform feeds, in placements ranging from instream pre-roll to muted outstream units, distinguished in the bid stream by the plcmt field.

When. Publisher video advertising was standardised with VAST in 2008, reshaped by muted autoplay from April 2018, reclassified by plcmt in March 2023 and is being redefined again through the IAB's RMT Standard in 2026.

Where. On desktop and mobile web pages and in apps, in players controlled by publishers, traded through ad servers, SSPs and DSPs using OpenRTB and VAST.

Why. Buyers split video budgets by environment and pay different prices for sound-on, chosen viewing and for silent units in a scroll. OLV names the open-web share of that spending, the smallest and slowest-growing of the three US video categories, and its value depends on whether placement signals are accurate.