The IAB Advertising Creative Guidelines for Display and Mobile have been updated to fully embrace HTML5 technology as the new standard for ad creative.
The audience capable of viewing Flash content continues to diminish. Mobile devices unable to play Flash content, combined with decreasing lack of Flash support among major desktop browsers, are rapidly accelerating this downward trend. HTML5 is the logical migration path for ad creative.
These creative updates are the result of testing diverse HTML5 ad creatives over a 4 month period for load performance and user experience to determine the optimum specifications for allowed file sizes and other HTML5 considerations. The test results were intensely debated by a cross-industry working group to establish the new specifications. The key goals for this update were to:
- Develop new creative specifications that allow creative vendors to continue building immersive ad experiences using HTML5 technology.
- Guide publishers on the updated file size limits necessary for executing HTML5 ads.
- Provide guidance on factors to consider when building and serving ads in HTML5 that maximizes page and ad load performance and minimize time to visual display of the ad in users’ browsers.
Availability and Adoption
Please be advised that these IAB guidelines represent an industry recommendation. Accordingly, not all publishers, nor all IAB member companies, adopt these guidelines without modification relative to their own unique business offering. Marketers, creative designers and media agencies are strongly advised to consult directly with publishers regarding their ad creative requirements.
Consumer Experience and Performance
The new guidelines adhere to the principles of positive consumer experience while balancing the requirements of publishers and advertisers, namely page load performance and the trend toward rich multi-media creative, with the assumption that the consumer’s primary purpose for digital publications is consumption of content.
- All specifications were determined upon extensive load performance and time to visual display performance criteria with a goal of about one second to visual display.
- New specification criteria were determined based on the one second to visual display goal with subload and file request limits that support HTML5 ad combinations of multiple file types, video lengths, and animation frames.
Publishers and ad servers are encouraged to take advantage of browser caching functionality by allowing use of common and popular shared libraries in HTML5 Ads. Doing so improves ad load and page load performance since the previously used shared library will not need to be downloaded again.
For the current release, file weights for these libraries must be included in the initial file weight calculations for the gzipped HTML ad, but publishers have the option to exempt certain libraries from ad file size calculation. During the publisher certification process, publishers must approve both the shared library and its source before the library can be exempted from ad file size.
Although website developers have been using shared libraries for some time, we must observe and monitor the use of shared libraries for ad creative before we can exclude them from file weight calculations. The impact of shared libraries in file weight calculations will be reviewed in 3-6 months time and an appropriate update made in 2016.
HTML5 Ads are like mini webpages that require a combination of multiple files and functions. The number of requests made to fetch files has a big impact on load performance of the ad as well as the page. HTML5 ads must optimize the number of requests being made to the server to reduce the impact on performance. For this release, a maximum of 15 file requests for initial file load is imposed to ensure little adverse effect on page load performance. This file request limit only applies for the file requests required to display the ad upon initial load. No file request limit has been placed on subsequent file loads.
Host Initiated Subload
A host-initiated subload replaces the “polite load” in the previous release. Polite load was not clearly defined. The host-initiated subload is defined as “the additional file limit allowed for rich media and Rising Star units that is auto-initiated one second after the domContentLoadedEventEnd occurs (web page content has been loaded) on the host computer or device. Only rich media and rising stars ads allow for the additional host-initiated subload.
File Weight Calculation
File weights are the total, gzipped file size of all the ad assets being delivered to the browser at a given phase. The three ad-load phases in this release include: initial load, host-initiated subload, and user-initiated load.
- Initial load – total, gzipped file size of all ad assets delivered to browser for initial ad display. It includes all files—images, HTML, CSS, JS, and any shared libraries or any other file type—required for initial ad display.
- Subload – additional gzipped creative assets allowed for some ads that may loaded no sooner than one second (1s) after the browser domContentLoadedEventEnd event is fired. The ad will need to listen for the browser event and build triggers for subload accordingly.
- User-initiated load – includes unlimited gzipped file load for any creative assets loaded after user-initiated ad interaction, like expansion or clicks. While no limits have been placed on user-initiated load, ad developers should consider user experience and load performance as part of their ad design. The assets for user-initiated ads should be optimized for load performance, and only necessary assets should be loaded.
Additionally, for ad units that allow video, another 1.1 MB of file size is allotted for auto-initiated 15-second videos, and 2.2 MB for auto-initiated 30-second videos in both display and mobile.
What is gzip?
All assets for HTML5 ads must be packaged together for delivery. To optimize the file size for delivery to browser, all assets should be delivered in compressed format. The common method for compressing files in transition over the Internet is the gzip utility, which is free to use and supported by all modern browsers. Ad servers compress ad files they serve as part of their general process.
HTML5 video cannot be streamed. Only progressive download is supported. However, standards exist to simulate streaming using an adaptive bitrate streaming format. This release provides guidance on how to format videos used in display and mobile advertising for optimal performance with HTML5 ads.