Whilst IP-based broadcast delivers innumerable benefits in terms of audio-visual delivery, the complexity of timing issues associated with IP can cause issues in terms of sync, not only between audio and video, but also additional elements such as subtitles. These individual assets generally maintain their own PTS (Presentation timestamp) within each stream, which can then be referenced against the PCR (Program Clock Reference) to ensure alignment. Whilst clock slippage necessarily constitutes a part of most major IP monitoring systems by virtue of the mandatory PTS Repetition check that forms part of the ETSI TR 101 290 specification, its analysis generally only goes as far as indicating presence of slippage. As such, it lacks diagnostic or predictive power. In SFN-based terrestrial networks or in head-end satellite ingest systems particularly, conventional clock slippage monitoring methods may often prove insufficient.

The two new standards, developed by Bridge, aim to address this issue. Through a more sophisticated understanding of difference values and their interactions and patterns, alarm trigger thresholds can be configured to identify and alert engineers to time slippage skew in much harder-to-detect contexts (including subtitling), and thus predict eventual errors far more promptly and accurately.

Bridge Technologies will be demonstrating the potential of these two new clock checks and associated alarms at the upcoming NAB2024 show in Las Vegas.