Thread: Lip Sync Issues

I'm using a Neusat SP6000 receiver to downlink RTN on AMC-9. This is an MCPC carrier with an east and west coast stream.

Somehow, during the course of the day, the lip sync seems to slip a bit either the east or west coast feed. I usually have to go in and change the Video PID, exit and then go back and change the PID back to its correct number in order to solve the problem.

My question is, why is this happening and why it continuing to happen? I rarely turn off the receiver and the antenna is fixed on AMC 9.

Thanks for the assist.

I see the same thing from time to time with a Coolsat 6100 and a Fortec Mercury II. Usually changing the channels resyncs things. It has been worse than nornal the last few days.

I asked this question a while back http://www.satelliteguys.us/free-air...ml#post1439214
The answer I got was:

Originally Posted by rv1pop

Brian, at SatelliteAV, gave me an explaination of that the other day. It is a function of the uplink quality, mainly, and something about resets, but there were some other things, too. Someone else will probably chime in with the full answer, but I lost the explaination about 30 seconds after that key thought.
But that was enough for me.
POP

If either the transmission or the receiver is not completely DVB compliant, the receiver does not properly sync the Audio (APID) and the Video (VPID) using the Program Clock Reference (PCR) information. This is equivalent to a film projector running with stripped out sprocket holes.

When a receiver is intially tuned, it correctly syncs the audio and the video signals using the PCR reference (usually the video PID). Consumer set-top boxes usually only sync when the channel is initially tuned, then the AV drifts apart as errors occur in the encoding /decoding. Professional receivers constantly reference the PCR to sync the AV and lip sync errors will not occur if the PCR is correctly referenced in the encoding process.

RTV seems to be operating on a shoestring. Their Video tape player on the East channel has not been tracking right for a couple of months.

Originally Posted by 1ADAM12

RTV seems to be operating on a shoestring. Their Video tape player on the East channel has not been tracking right for a couple of months.

"Seems to be" is definitely an understatement. They have potential.

Reminds me of an old independent we used to have in VT. WWBI TV27. You used to see whatever channel their VCR was tuned to if the tape ran out and no one was around to change the program. They also had very limited programming at startup. I remember at one point they showed Kung-Fu for 2 days straight.

Originally Posted by 1ADAM12

RTV seems to be operating on a shoestring. Their Video tape player on the East channel has not been tracking right for a couple of months.

Are they really still using VTR's? One computer for each feed with NAS looks great and costs little.

Many TV stations are still using tape extensively, although I expect it will slowly fade into history. They have to justify the enormous expense of these professional VTRs, and also, I would think many have a large tape library.