This policy applies to AdSense publishers, and Google Ad Manager Partners using Google Monetization (Preferred Deals, Programmatic Guaranteed, Private Auction and Open Auction), who monetize with video ads in auction, including ads shown in in-stream content, audio content, or non-in-stream video placements (for example, games, in-article, in-feed). Anywhere a video ad is eligible to serve (in a game, in a video player with in-stream video, or in a standalone non-in-stream placement) is considered the video ad placement.

Policy requirements are organized under these key principles:

• Use supported implementations
• Accurately describe inventory
• Protect advertiser value
• Respect the user

Specific ad formats also have their own, additional requirements:

• TrueView and skippable video ads
• Non-in-stream video ads

Use supported implementations

Use of supported Google video implementations is required in order to allow us to optimize user experience, support brand measurement, protect against invalid traffic, and render proprietary formats such as TrueView.

• In-stream ads: Video ad placements next to video or audio content must use the Google Interactive Media Ads SDK or the Google Mobile Ads SDK on supported platforms, unless through an official Google Beta program.
  • Publishers cannot use interactive media ads products to monetize YouTube-hosted content. For YouTube content, publishers must monetize through the YouTube Partner Program.
• Non-in-stream ads: To be eligible to serve video ads outside of a video stream, video ad placements must use Google-provided solutions: on web, Google Publisher Tags; in app, the Google Mobile Ads SDK. These video ad formats include: in-banner video ads (including in-article and in-feed video), native video ads, interstitial video ads, rewarded video ads, and app open video ads.
  • The Google Interactive Media Ads SDK is not allowed for non-in-stream placements, except for placements in games.

Accurately describe inventory

Use metadata and declarations to accurately describe inventory so that advertisers are correctly informed where their ads run.

• Ensure that high-quality, accurate metadata and description URLs are provided and maintained for all monetizable video & audio content, as well as for web games (See Ad Exchange video tag parameters for IMA3).
• Video ad placements must either be audible by default or properly declared as a muted placement.
  • For non-in-stream placements using Google’s format libraries, muted declarations are automatically handled correctly.
• Only serve in-stream video ads to valid in-stream placements, which excludes:
  • Video slideshows highlighting content available on a site without original video content.
  • Video ads in a display banner ad on a web page or app.
  • Video ads in the rail of the page, such as in a 300×250 slot on desktop.
  • Video ads in placements with no accompanying video content, apart from non-in-stream placements.
  • Video ads in placements that cycle between display ad units and video ads, whether or not there is accompanying video content.
  • In-banner video ads which do not load a video player.
• Accurately declare video ad placement size.

Protect advertiser value

To protect advertiser value, users need to be able to engage with video ads. Video ads must render properly in video ad placements. Video ad placements must avoid surprising users or behaving in unexpected or non-standard ways.

• All video ad placements must maintain a standard aspect ratio of 4:3 or 16:9 for horizontal videos; 3:4, 4:5, or 9:16 for vertical videos; or 1:1 for square videos.
• Video ad placements for in-article and in-feed video ads must be at least 256 pixels in both their longer and shorter dimensions (with the exception of 300×250 and 320×180, which are also permitted). All other video ad placements must be at least 256 pixels in their longer dimension, and at least 144 pixels in their shorter dimension.
• Do not obscure, hide, remove or change the rendering of any ad content or ad controls.
• Ads must not be placed in proximity to or obstruct game or video player controls (play, pause, volume, and so forth).
• Ads must display until the user navigates away from the page or content, unless otherwise noted for specific ad formats (see Additional requirements for specific ad formats, below).

Respect the user

Video ads must serve in an environment that is respectful of users’ experience and time:

• For in-stream ads, the sum duration of video content must exceed the sum duration of video ads.
• For non-in-stream video ads, including ads in games, the amount of content experienced by users must exceed the sum duration of interstitial ads.
• Ads must not autoplay below-the-fold, nor may ads play on hover.
  • Autoplay is only allowed when at least 50% of the ad unit is visible: on a 1024×768 viewport for desktop; on a 360×600 viewport on mobile.
• No more than one video ad placement may play in view at any given time.
• Additional policies apply to video ad placements in a sticky video player (a video player that remains in a fixed location on the screen):
  • A sticky video player must start out as an in-page video player that is not sticky.
    • As the user scrolls the page, the video must transition from playing in the in-page video player to playing in a sticky video player, which remains in view as the user scrolls the page.
  • The in-page video player must be fully viewable on the page before transitioning to the sticky video player.
  • If the sticky video player has more than one edge overlapping in-page video ad content, in-page ad content, in-page content, or in-page navigation, the sticky video player must include a dismissal feature.
    • The dismissal feature must be visible without needing the user to hover over or tap on the video.

Additional requirements for specific ad formats

TrueView and skippable video ads

Google Ads allows advertisers buying on YouTube to extend their budgets to sites and apps that partner with Google, including using our proprietary TrueView format. To be eligible to receive skippable ads, including TrueView ads, these additional policies apply:

• Video ad placements must be audible by default.
• Scroll-to-play ads are not permitted for TrueView.
• For mid-rolls, the video content’s duration must be at least 10 minutes.

Non-in-stream video ads

Video ad placements that do not have accompanying video can include: in-banner video ads (including in-article and in-feed video ads), native video ads, interstitial video ads, rewarded video ads, and app open video ads. Learn more about out-stream video ad formats.

To be eligible to receive non-in-stream ads, these additional policies apply:

• Clearly be identified as advertisements. Learn more about ad attribution.
• Autoplay, apart from interstitial and rewarded video ads, must be muted by default, unless the user has explicitly opted to turn on sound.
  • For interstitial video ads, audio can be turned on or disabled on initial load, subject to the user’s phone settings. For example, if an interstitial loads when the user’s phone is sound off, the interstitial must load in a muted state.
• May begin playing only when at least 50% of the pixels in the player are visible in the viewport and must stop playing when fewer than 50% of the pixels in the player are visible in the viewport, unless the user has interacted with the play button in the video ad controls.
  • Interstitial video ads only play when fully in view.
• Cannot cause the page to reflow its layout before, during, or after the video ad renders. In other words, the placement must not shift the content up or down in the user’s viewport. The placement must not expand to full screen on scroll over.
• Other than interstitial and rewarded video ads, must scroll along with the other content in the app or page. No sticky implementations are allowed.
• In-article video ads must be placed between paragraphs, and in-feed video ads must be placed within a feed of items.

Source : https://support.google.com/admanager/answer/3522024?hl=es