Denon 500 loosing zoom

[Ged]

Watched Gladiator last night on our 20" 4:3 ratio telly and zoomed it a little to fill the screen.
After a while the zoom switched off, switched it back on and off it went again :confused:
I did a little forward/rewind and it switches at certain fixed points on the disc, I am not that fussed as it only used in the conservatory but wondered if this a common fault?

[Strangerer]

The zoom function is something I'll never use as PQ suffers terribly. Its just a gimmick that serves no practicle use. Whilst on the subject of features, what is the dialogue speed up mode on the Denon 550 about? Why would you need to use it? How does it work? The image and the voices speed up but the pitch of the voice stays the same. :confused:

[Ged]

I have never seen the dialogue function, where is it mentioned? Could it be an audio delay?