Triple-Play Service Deployment

Chapter 6: Troubleshooting Video in the Headend
Figure 6.7: Visibility of all PIDs in the MPEG transport stream gives the user an ability to validate
that the right data is on the right PID, as well as a means of idenitfying individual rates for audio,
video and Null PIDs.
Beyond TR-290
Further, there are issues that exist beneath the surface—problems
that technically are not illegal to an MPEG transport stream, and
therefore will not trigger an alarm in TR 101-290. A common
assumption is that digital programs contain only audio and video
pairs. While this is the most common scenario, MPEG transport
could also carry digital radio services, or datacasts, among others.
In those cases, it is valid for a program to have a PCR PID mapped
to an audio PID, or programs with an audio element and no video.
If by chance a traditional program (video and audio) should lose
the video PID and the PMT reference to video, there will be no
alarming against TR 101-290.This is also true when a PCR has been
inserted on both the video and audio components. There will,
however, be noticeable presentation issues at the set top box.
These problems all require comprehensive visibility into the MPEG
transport stream to check the structure of the stream and confirm
the presence and even the rate of each element. The following
examples illustrate the steps of MPEG troubleshooting.
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