When delivering content to a large global audience, it is critical to ensure optimized delivery of your content. This new capability is targeted to accelerate and optimize performance based on the scenarios you may use Azure CDN to deliver. These scenarios can include general website or web application delivery, media streaming, file download, etc. Optimization will be applied by default to the scenario you specified in the "optimized for" option when you create a CDN endpoint.
Optimization that we apply includes caching, object chunking, origin failure retry policy, among others, depending on the specific scenario. Media streaming is time sensitive in that packets arriving late on the client can cause degraded viewing experience, for example, frequent buffering of video content. The new enhancements, reduces the latency for delivery of media content. For large file download, object chunking is critical. Files are requested in smaller chunks from the origin to ensure a smooth download experience. We apply these enhancements based on the experience with many customers and we will continue adding additional settings to improve content delivery performance.
Read about it on the Azure blog.