Techniques for dynamically changing characteristics of simulcast video streams in real-time multi-party video conferences. Once a video conference has been established for a plurality of participant devices, each participant device can provide a notification of its supported video communications characteristic(s) for sending simulcast video streams and receiving video streams. Having been provided such notification, the media server can determine video communications setting(s) and/or parameter(s) to be used by each participant device while sending simulcast video streams or receiving video streams based on the supported video communications characteristic(s) of the respective participant devices. In response to changes in conference, system, or network factors, the media server can request one or more of the participant devices to dynamically change the video communications setting(s) and/or parameter(s) used to send simulcast video streams or receive video streams to maintain acceptable levels of QoE at the respective participant devices.