Abstract: Network nodes (12, 14, 16, 18, and 20) that exchange time-dependent data in accordance with the Real-Time Transport Protocol subject the timestamps of incoming packets (FIG. 1) to tests that indicate whether the timestamps were likely generated correctly. Such a no de begins an RTP session by determining its output in accordance with the incoming packets' times of arrival. It thereafter bases its output's timing on the incoming packets' timestamps if previously received packets have passed a test (FIG. 5) that indicate their timestamps' reliability. While such a node operates in such a timestamp-based output-timing mode, it continues to test incoming timestamps and assumes operation according to the time-of-arrival mode if too many packets fail the timestamp-reliability test.

Abstract: The method and apparatus related to macroblock parsing in a GOB to comply with a maximum-transmission-unit size is described. The real-time transmission protocol (RTP) suggests that the RTP packet sent be smaller than the underlying transport mechanism. In the case where video streams are encoded under ITU-T H.261 recommendation, certain group of blocks (GOBs) exceed the allowable packet size. For end-points such as a terminal, implementing a macroblock parser is a natural outcome of the encoding process. However, for other devices, such as a multipoint control unit (MCU), a marcoblock parser is not that easily implemented. Thus, instead of using a macroblock parser, the incoming packets are monitored for partial GOBs. A partial GOB is where the GOB was previously parsed into portions by a device for compliance. Once a partial GOB is detected, pertinent information pertaining to the macroblock fragmentation is then retrieved and stored for future use.