VAST Video







Video Format

VAST: Android: MP4, 3GP, WebM, X-FLV, X-M4V iOS: MP4, 3GP, Quicktime, X-M4V VPAID: application/JavaScript

Aspect Ratio

16:9 for landscape video

9:16 for vertical video

Maximum Video File Size

30 MB (Recommended file size ~3 MB)

Video Length

180 secs (Recommended file size < 60 sec)

Video Frames

Max 30 FPS

Audio Format

MP3 or AAC Preferred

Companion Ad





Smartphone for landscape video - 568x320, 480x320, 300x250

Smartphone for vertical video - 320x568, 320x480, 300x250

Tablet for landscape video - 1024x768

Maximum File Size

100 KB

Companion Type

Static Resource only (Recommended), HTML Resource, iFrame Resource


We support VAST protocols up to VAST 4.1. VAST tags that contain multiple media files should have the following required attributes:

  • Delivery: progressive
  • Width: the native width of the video file, in pixels
  • Height: the native height of the video file, in pixels
  • Bitrate: average bitrate of the media file.

The VAST tag can contain a companion ad in a PNG/JPEG format.

VPAID should be embedded in the VAST response.

  • Format supported: HTML5, JavaScript
  • oRTB ad request includes: 1,2
  • VPAID should be sent to the video player in a VAST response and referenced as shown below:
    • Media file type: application/JavaScript
    • API Framework: VPAID
    • Delivery: progressive

Aspect Ratio

  • 16:9 for landscape video. Recommended dimensions of the video are: 1280x720, 854x480 or 640x360.
  • 9:16 for vertical video. Recommended dimensions of the video are: 720x1280, 480x854 or 360x640.​
  • In the case of the screen or device re-orientation, creatives will be padded with black space to fit the 16:9 or 9:16 video player aspect ratio. ​
  • Multiple media files (having various bitrates) matching the above spec are strongly recommended. ​
  • InMobi SDK picks up the best matching media file based on network connection speed and device type.


Recommended to have one video file having bitrate <= 1024 kbps


There is no hard limit on the video bitrate. However, the video bitrate combined with the video duration should net out to a file size lesser than the max video size (10MB).

Audio: AAC constant bitrate, 2 channels, 44.1KHz sampling rate.


Third-party viewability measurement verification support across MOAT, IAS, DoubleVerify, Google ActiveView, and Meetrics through Open Measurement SDK (OMSDK)​.

Companion Ad Format

  • Image sizes recommended:
    • Smartphone for landscape video: 300x250, 568x320, 480x320 - Based on the requested slot of the device, the relevant size will be picked up where available. ​
    • Tablet for landscape video: 1024x768​
    • Smartphone for vertical video: 300x250, 320x568, 320x480 - Based on the requested ad slot of the device, the relevant size will be picked up where available. ​
    • Tablets for vertical video: 768x1024​
  • Max file size: 100 KB
  • Formats supported: PNG, JPEG, HTML


  • Must be served via a linear VAST tag (pre-fetch tag)
    • Companion ads:
      • Rendered as end-cards, centered on the last frame of the video
      • Tracking Events - view, click
      • Companion ClickThrough
    • All VAST versions are supported.
    • Maximum of 3 VAST wrappers allowed.
    • CORS header mandatory for VAST response (including wrappers)
    • Only one creative per VAST tag; if there are multiple creatives, only the first one is picked, and the rest are ignored.
    • The VAST tag must be SSL-compliant.
    • Non-Linear Video not supported
    • For Rewarded Videos, all oRTB requests will include an extended field under Video Object confirming whether "Rewarded =True / False“.

End-card Requirements

End cards can either be designed by InMobi’s creative team or the client.

Requirements For End-Cards Designed By Client

  • Aspect Ratio: Both Vertical and Horizontal supported (depending on the video orientation).
  • Design resolution: 640x1136 or higher resolution.
  • Use responsive design principles to ensure objects shift to fit all screen sizes, as some screens are now taller than the standard.
  • Use smart objects at high resolutions to resize the elements if needed.
  • Provide any fonts used in your PSD in case type changes are needed later on. Most licenses allow you to share fonts with vendors for publishing.
  • We usually use Celtra for building rich media. Some components, such as maps, may have design restrictions.
  • Keep logos towards the top of creatives for best brand recognition.
  • Use a button for the main CTA. CTA button should be near the bottom third of the screen, where users’ thumbs naturally rest.

Requirements For End-Cards Designed By InMobi

Provide us the following assets:

  • Logo files
  • Brand Fonts
  • Style Guide
  • PSDs from any existing marketing material (display, print, social media, web)
  • Photographs (products, lifestyle shots, etc.)





In-App Interstitial


Smartphone for landscape interstitial 568x320, 480x320, 300x250
Smartphone for vertical interstitial 320x568, 320x480, 300x250
Tablet for landscape interstitial 1024x768

Max Size Initial Load

200 KB

Max Load Size

500 KB



Standard Display

Max Size Initial Load

320*50 Static Banner – 20kb
320*50 Animated HTML5- 200kb 300*250 Static Banner – 40kb 300*250 Animated HTML5 – 200kb

Max Load Size

500 KB



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Last Updated on: 05 Oct, 2022