Rob, there are 3 implementations of Avigilon HDSM: JPEG2000, H.264 multistreaming (all their current cameras except for the new Pros and the Pro H.264 series with their "HDSM 2.0" implementation.
Most VMSes support H.264 multistreaming so you can stream low resolution when viewing multiple cameras simultaneously and then switch to high or full resolution when viewing one camera individually. Those operate cross platform on many VMS and camera combinations.
Avigilon's H.264 Pro cameras do more than just multi-streaming, but they are Avigilon's most expensive cameras and proprietary to them. We have not tested HDSM 2.0.
Avigilon VMS supports most HDSM features with third-party cameras that are powerful enough to generate simultaneous streams of different quality and resolution, so it's cross-platform but you should test each camera first. Their highest resolution pro cameras extend ONVIF to further divide streams in multiple video tiles and allow for a smoother monitoring experience when viewing many cameras and zooming on specific areas. Other VMSes tend to overload and skip frames when handling 4K and above material so I see that as a bigger usability benefit than the bandwidth and storage management.