A packet structure for a Mobile Display Digital Interface (MDDI) includes a flexible sub-frame length to efficiently transmit large packets. A windowless video stream packet avoids repetitive transmissions of video packets when some parameters are unchanged, saving bandwidth. An enhanced reverse encapsulation packet combines the feature of a separate round trip delay packet with a separate reverse encapsulation packet. A link freeze is used to halt a transmission of a data stream at any point in the transmission and resume the transmission by a host.