Sony VTX-750 Digbox sound sync problem

[pwhite8314]

This is a weird one - I've just installed a Sony digibox to replace my aging and unreliable Amstrad. I know the optical out only supports Pro-logic, but I figures it was still better than the analogues, so connected it up. The sound is fine, but is about 2.5 seconds ahead of the picture

I've forced a new s/w download, tried other optical leads and swapped inputs on the amp (not that any of this could logically make a difference), but it's still ahead of the picture, even when viewed via TiVo, which adds just under 1 second delay.

The cynic in me would accuse Sky of deliberately screwing up the optical out, but I doubt even they would go this low, and if they did, they'd probably just turn it off altogether.

Any ideas? The analogue output is fine.

[Starburst]

Well on the surface if the audio is 2.5 seconds ahead of the video then that would point to a huge delay in video processing not audio.
I am far from being an expert but I can't imagine a situation where video processing is normal and the audio processing can be output from a digiboxes optical port ahead of time, of course a delay could be generated after the data leaves the digibox.

Are you using a plasma display by any chance?
I have read that the added video processing time needed to generate the image can cause audio from a seperate AV amp to be output ahead of the display. Basically the amp and plasma get the data at the same time but the plasma can't process it fast enough to maintain synch with the audio.

Then again you say the analogue output is fine, so that ruins a perfectly good theory

[pwhite8314]

Yep, with a Plasma, but as you say, the analogue sound is fine.

I've never seen anything like it; if the analogue sound wasn't fine, or if it was lagging behind then I'd suspect a fault, but as it is it just doesn't make sence.

Everything was fine with my Amstrad!? (never thought I'd say that!)

[Starburst]

Daft question probably but assuming you have a dvd player is the audio/video sync ok when you use the optical output on the dvd player connected to the same optical input on the amp that you are using for the digibox?
Another daft question, are you routing all video and audio through the AV amp and if so have you tried connecting the video directly.

[pwhite8314]

Starburst - not tried the same optical in for the DVD - will do later. Only the audio goes via the amp, video is switched by the tuner.