How does Phenix handle adaptivity for challenging internet connections?
Phenix proprietary Adaptive Bitrate technology (United States Patent Application No. 62/663,182) transcodes streams into multiple resolutions and bitrates, enabling each viewer to dynamically receive the bitrate most suitable to his or her connection speed at any given time. All of this is accomplished while maintaining less than 500ms of end-to-end latency. The Adaptive Bitrate (ABR) capabilities for optimal stream quality are handled by the Phenix system according to each individual viewer’s network conditions.
The default ABR policy uses a resolution bitrate ladder similar to YouTube recommendations. Phenix will automatically transcode to the applicable quality layers below the published quality level. For example, if you publish an HD stream as the top layer, then Phenix automatically creates the appropriate SD, LD, VLD and ULD layers.
There are no special requirements on the viewer side to enable ABR streaming. Phenix will automatically connect viewers to the highest quality layer that is sustainable for their network connection. This differs from other technologies such as DASH, which requires the viewer side to parse a manifest and choose a presentation based on bitrate and other factors. Viewers will switch between quality layers as needed throughout the duration of their streams.
Phenix real-time streaming is a packet based frame-by-frame approach, in contrast to the chunk-based approaches of HLS and DASH. Phenix uses a proprietary algorithm and architecture for dynamic keyframe generation that scales across large audiences in order to allow switching quality levels at any time for any viewer.