Reduction of latency in video distribution networks using adaptive bit rates

摘要

Systems and methods are provided for reducing and controlling playback latency in an unmanaged, buffered data network. A delay cost function is determined, the function representing the effect of playback latency on end user experience. An encoder transmits audiovisual data through the network to a client device. Network latency is measured, and the delay cost function is evaluated to establish an encoding bitrate for the encoder. The encoding of the audiovisual data is altered in response to dynamic network conditions, thereby controlling end-to-end playback latency of the system, which is represented by the playout length of data buffered between the encoder and the client device.

主权项

1. A method of controlling playback latency associated with transmission of source audiovisual data through an unmanaged, buffered data network, the method comprising: at a server system coupled to a client device through the data network:
encoding a first portion of the source audiovisual data into a first portion of transmission audiovisual data at a first encoding bitrate; buffering the first portion of transmission audiovisual data; transmitting the first portion of transmission audiovisual data to the client device through the data network; calculating a delay cost function based on a delay associated with the buffering and with network delay, raised to a power, scaled by a scaling factor, and added to a minimum cost to transmit data; altering an encoding bitrate from the first encoding bitrate to a second encoding bitrate based on the calculated delay cost function; encoding a second portion of the source audiovisual data into a second portion of transmission audiovisual data at the second encoding bitrate; buffering the second portion of transmission audiovisual data; and transmitting the second portion of transmission audiovisual data to the client device through the data network.