With long latency times clearly the next great video streaming obstacle to be conquered, content delivery network (CDN) Akamai announced support for ultra-low latency streaming using CMAF and chunk transfer encoding. In a blog post, Akamai chief architect Will Law explained how this solution breaks with the common wisdom that all HTTP Adaptive Streaming (HAS) content includes latency that’s several times the length of each delivered segment. Using Ultra-Low Latency Common Media Application Format (ULL-CMAF), operators can achieve latency that’s less than the length of one segment.
How low can this go? Law says 600ms is possible, but that those kinds of results “are excellent for impressing friends and CEOs, however they become increasingly fragile with scale and with geographic dispersion.” A glass-to-glass latency of 3 seconds is more realistic, which is still far better than the 30 seconds or more that many live video providers currently offer.
Simply using CMAF segments themselves isn’t enough to reduce latency, Law stresses. “To obtain low end-to-end latency, the CMAF containers must be paired with encoder, CDN and client behaviors so that the overall system enables low latency.” The full blog post spells out these technical requirements. While the industry isn’t there yet, all the components needed to make the ULL-CMAF workflow a reality are seeing “broad improvement,” he notes.