Patent ID: 8699351
Filing Date: 2014-04-15
Classification: H04L,H04N

Abstract:
1. A packet transmission method, comprising: receiving an uncompressed television program signal; packetizing the television program signal into an IP television program signal comprising a video packet stream including a video packet and an audio packet stream including an audio packet corresponding to the video packet; including a video counter value in the video packet; including an audio counter value corresponding to the video counter value in the audio packet; including a program clock value, distinct from the video counter value, in the video packet, wherein the program clock value is associated with a program clock synchronized with the IP television program signal; transmitting the packetized IP television program signal over an IP television network; recording a first arrival time of the audio packet arriving at an IP television network node; recording a second arrival time of the video packet arriving at the IP television network node; determining a first synchronization offset based on a difference between the first arrival time and the second arrival time; obtaining the program clock value from the video packet; determining a second synchronization offset based on a difference between the first arrival time and the program clock value; determining a third synchronization offset based on a difference between the second arrival time and the program clock value; maintaining, for each of a plurality of network nodes, historical values of the first synchronization offset, the second synchronization offset, and the third synchronization offset; and determining from the historical values, individual network nodes producing offset values exceeding predetermined thresholds.