Downgrading your iPod Touch should not delete anything.
You can't downgrade an IOS on your iPod Touch.
You can't downgrade IOS!
No. You must restore to Downgrade the Firmware!
Yes
When restoring your Ipod Touch the data on itunes doesn NOT get deleted. :D
you dont
I have never heard any way to downgrade software.
You cannot downgrade an iPod touch with with another iPod touch's shsh blobs because the shsh blob is unique to that device. Think of it as your DNA is unique nobody can be exactly like you.
No, updating an iPod will not delete anything on your iPod.
Well it's kind of IMPOSSIBLE
You can open the settings app and go to General->Usage There you can delete data from apps. This will delete all the videos and if your looking to delete a few videos and it won't then I don't know what to do for you except restore which will delete everything off your iPod.