Film-Tech Forum ARCHIVE: NT Live sync problem on Icecrypts

This is topic NT Live sync problem on Icecrypts in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Jonathan Greer (Member # 9151) on 12-05-2018, 03:45 PM:

Hello all,

We have been having a problem specifically with NT Live shows lately where the lipsync is out. No problems with any other satellite transmissions (ROH Live on Monday was fine). As far as we're aware we are the only cinema having this issue and the sync is fine at their end, plus NT Live uses the same AV encoding as any other live transmission.
At first it seemed the problem only occurred in cinema 3 but during the test this morning the sync was out in both cinemas 2 and 3. Our receivers are Icecrypt STC6000HD PVR.
Has anyone encountered anything similar or have any suggestions? I saw a thread where someone had issues specific to NT Live but they had the signal cutting out entirely rather than sync problems.
It's just baffling that it should be only the combination of NT Live and our equipment that has a problem. Could it be something to do with how the receivers decode streaming content, or the Dolby decoder?

Posted by Pete Naples (Member # 761) on 12-05-2018, 03:53 PM:

Have the dish and LNB critically checked out by a good satellite engineer.

It seems to be common practice to Icecrypt boxes to factory reset them before each show.

It could be that you sync is actually always slightly out, and that NT live are slightly out. 2+2=4

I invested in a sync meter because I found if you put 8 people in a cinema, you'll get 5 different opinions on where sync is.

Posted by Jonathan Greer (Member # 9151) on 12-05-2018, 03:59 PM:

Thanks Pete, SCCI are coming tomorrow morning to check the dish.
We have a second dish currently pointing at 9-05. I'm wondering if it's worth aligning this to 10-02 in parallel to the 1st dish in case the bug lies somewhere between the 1st dish and our comms room.
We're looking to get LANsat installed soon, but the immediate problem is the NT Live show tomorrow!

Posted by Steve Moore (Member # 4753) on 12-05-2018, 07:03 PM:

I had problems in the past with NT but not with the Icecrypt, with the humax that I ran in parallel as a backup (using a satellite splitter, which I know is not good practice in itself) My Icecryot was always in sync but the humax was out. Simply unplugging and re-plugging the HDMI put that back in sync.
We have since moved to LANsat and that has been far more stable for both picture and sound (never had any sync issues and much less prone to drop out)
It could be worth having your 2nd dish pointed at 10-02 now, as I most people seemed to have stopped transmitting on 9-05.
Out of interest what sound processor do you have? When i lost sync on audio with the Humax it was feeding a Cp750 via coax. Pulling and replugging the HDMI lead put everything back in sync straight away

Posted by Jonathan Greer (Member # 9151) on 12-16-2018, 03:32 PM:

Thanks for the feedback, I wasn't actually working the NT Live show but it was fine in the end.
For the record, the people who were working that day took the following steps, in the suspicion that something in our HDMI chain may have been causing the video to take longer to process than the audio, introducing the sync error:
The engineers tested our dish alignment and aligned both dishes to 10-02.
We removed fibre and HDMI splitters from the setup, patched both dishes directly to the one cinema and factory reset both receivers.
The sound was originally fed via SPDIF optical > DMA8 > CP650. For the event we de-embedded the audio and fed it via coaxial to the DMA8 as an alternative.

All OK in the end, but I'm glad we're installing LANsat. Thus far I've heard nothing but good things about it.