I'm sorry to let u know there's no possiblity of no lossing any quality if re-encoding. Since the frame rate has neen changed from 29.97 to 25, the quality must be affected.
And as for how to convert it. I googled and found a forum which mainly discussed about NTSC and PAL. hope it helps.
http://www.google.com/support/forum/p/Google%20Mobile/thread?tid=57e429f4ce...
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Laura
Laura Wood