[Phil Reid]

I've got my Foxsat box connected to a Pioneer 508XD by HDMI for video, and to a Pioneer VSX-AX5i receiver by optical lead for audio.

My simple understanding is that lipsynch issues occur because of the slight difference in connection speeds between the two. If this is the case, why does the lipsynch adjustment need to be changed from one day to the next?

On Wednesday night I had to set it to 160ms to correct the problem, and this worked for all Freesat channels. Last night I had to reset it to zero, because there was no lipsynch delay.

If lipsynch issues are down to hardware connections, why isn't the problem consistent?

Sorry if I'm being thick.

[u006852]

Hi

You need to add a delay to audio because the video processing in the plasma takes a finite amount of time. This varies from display to display, can be as small as 40 ms. Not saying that 160 ms is wrong, but it does sound a little large.

Now it is difficult to set this accurately but the BBC have a special test card to do just this.

Read this blog from Andy Quested at the BBC.

BBC Internet Blog

Now, the delay should be constant and not need adjusting.

Are you setting the delay in the sat receiver or the amp?

[grahamlthompson]

Originally Posted by Phil Reid

I've got my Foxsat box connected to a Pioneer 508XD by HDMI for video, and to a Pioneer VSX-AX5i receiver by optical lead for audio.

My simple understanding is that lipsynch issues occur because of the slight difference in connection speeds between the two. If this is the case, why does the lipsynch adjustment need to be changed from one day to the next?

On Wednesday night I had to set it to 160ms to correct the problem, and this worked for all Freesat channels. Last night I had to reset it to zero, because there was no lipsynch delay.

If lipsynch issues are down to hardware connections, why isn't the problem consistent?

Sorry if I'm being thick.

Sometimes simply tuning to a different channel and then back to the problem channel, fixes lip synch. At a guess it forces a resync of audio and video

[Phil Reid]

Originally Posted by u006852

Are you setting the delay in the sat receiver or the amp?

I'm setting it in the Foxsat box. It's the lack of consistency that confuses me.

Thanks...

[FISHGUTS]

I had bad sync problems with the footy on ITV last night

[u006852]

Try setting it to zero in the foxsat and use the BBC testcard to set the delay in the amp and see what happens.

[Chris`I]

As u006852, this delay (the one you can alter) is fixed and should only need setting once on the Foxsat box. The fact its changing suggests that it is a delay caused in the transmission chain rather than your end. As the BBC blog says, they go to great lengths to reduce it, but maybe other channels dont. Give the BBC audio testcard a wiz and see if its out of sync on that. I'm guessing it wont be, which means its the other providers that are out of sync somewhere in their chain, which can happen easily in live broadcasts I would guess they have significantly less control over the transmission chain. They should have someone monitor it really!

[Stephen Neal]

Lipsync delay isn't always caused by the transmission chain (if you mean the broadcaster bit) - it can also be caused by the receiver (Some Sky HD boxes have a known fault at the moment)

Similarly some receivers lose lip-sync when they get errors in the audio or video stream - and in this case changing channels can sometimes solve this as it re-syncs stuff.