Audio / video sync drift

[philper]

You say "drift". But you also say that sync is good on their end until 30 min. Does that mean sync is also consistent there too, like NOT drifting but continuing in the same sync relationship until 30 min? This is an important consideration. "Drift" means that the sync is never stable, that it is changing all the time--often do to frame rate or clock diffs in recording or post. If the sync is jumping out @ 30 min, by how much is it jumping out, does it stay out by the same amount or does actual "drift" start happening then? Besides asking a lot of questions about how they are importing your mix, you might get them to make you a dub of the picture with your sound so you can see the sync issues on your own system.