VAST file recommendations

When creating a VAST ad item, we recommend that you upload multiple copies of the ad creative using different file formats, resolutions, and aspect ratios. This ensures maximum compatibility with common VAST-compatible video players.

To upload additional VAST files to your ad item in Adbutler, use the button at the bottom of the ad item setup form.

Include additional files

Filename, format and resolution


Use only alphanumeric characters for the names of media files. We also recommend that you use camel case, include the resolution, and seperate details with an _. For example: FallFishingPromo_640x480.mp4.

Resolution and Aspect Ratios

Include enough options to allow video ads to render in any player size. Include a range of high, medium and low quality options and cover the three most common aspect ratios: 4:3, 16:9, and 5:2.

File types

Video: For maximum compatibility, upload H.264 (MP4) and WebM copies of the file.
Audio: MP3 or AAC

Video Length

Maximum: 60 seconds

Frame Rate

Maximum: 30 FPS

File size

Maximum: 50MB
Recommended: Less than 3MB

Please ensure that your video files are optimized for web playback to reduce latency and CDN usage.

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