azurevideo-streamingstreamingazure-media-services

Why does the Azure Media Services Verizon Premium CDN Streaming Endpoint actually create more latency when compared to the default non-CDN option


I have a use case which is a many streams to 1 - 15 person viewing need. More so closer to the 1 - 3 person viewing need. So 1 stream to 1 - 3 people. I need to scale that outwards as well having multiple streams going at once.

I am not an expert in CDN's but my observations is that the default standard Stream Endpoint is more performant than the premium Verizon CDN I've setup.

This is odd to me for 2 reasons. 1. It's not on a shared Stream Endpoint which is what the standard default is. and 2. It's a CDN which is supposed to get more people to a link of content closer to their physical location.

Based on my use case perhaps a CDN is not necessary if the sole purpose of the CDN is to get the content "closer" to the physical location of viewing the stream.

Is there a setup I should try to help with the low latency of a CDN stream?


Solution

  • CDNs are meant to act as caches for video fragments that are requested multiple times from a Media Services Streaming Endpoint. Instead of a client requesting the video directly, the client requests it from the closest CDN PoP (point of presence). This ensures that the video is cached relatively close to that client. If multiple clients in the same area request the same video, then it can be delivered from cache. Cache deliveries tend to be fast compared to cache misses.

    The CDN does add an extra step to the path between a client and Streaming Endpoint. Sometimes that extra step can add a small bit of latency to the stream. For this reason and the low number of users it is unlikely a CDN would be beneficial in the scenario you described. With only 1-3 people watching a stream almost all of the video fragment requests will be cache misses.