Microsoft has reduced Microsoft Teams' power requirements by 50% since June 2020.
Outlined in a blog you can read here, Microsoft began by looking at the differences in power requirements for different customer profiles by ensuring Teams meetings are as energy-efficient as possible, regardless of setup.
It created a test framework to measure power consumption for important meeting scenarios such as group video calls and screen sharing, which often involve energy-intensive processes such as content capture, encoding, and rendering. The next step was to evaluate these processes and identify opportunities to optimise the efficiency of each. Isolating and optimising each of these processes enabled us to reduce power consumption up to 50% for energy-intensive scenarios such as having over 10 users in a meeting when everyone has their video turned on (see figure below).
During the evaluation of the video capture process, Microsoft focused on camera optimisation to reduce demands on the CPU when using video in meetings, improving configurations, reducing code complexity for auto-exposure, auto-white balance, auto-aliasing, resulting in power draw reduction from the onboard camera and stability enhancements, and face detection processes.
Then, it turned to video rendering, particularly for meetings with many participants, where the users receive a video stream for each participant displayed in the Teams client. Incoming videos can have different resolutions that require the client to rescale each. A simple 3x3 video grid once required nine distinct rendering operations. By combining the streams and composing them into a single video, it was able to consolidate operations in video rendering and significantly reduce the power requirements for each device used.