What do the logos appear like on teaser trailers?

On here, the logo flashes up immediately after the green-backgrounded 'preview' notice of 5 seconds, and takes 2 seconds. The music plays over it.

Heres another teaser trailer:

This is Harry Potter which is, and has always been, associated with Warner Bros. This logo shows up for 5 seconds. Im not particularly sure if this is the theatrical trailer or not as there are so many different versions claiming to be teasers when they are not! Looking at the running time, I think that it is.

Here is another teaser trailer. I know this because it gives away little about the film, apart from the fact there are lots of really good actors in it. The undecided exact date at the end 'February 2010' also gives me this impression. The logo of the distributor is almost subliminal right at the beginning. It lasts about 1 1/2 -2 seconds.

There are two on this one. The first logo takes about 3 or 4 seconds and the second logo (twisted pictures) takes about 2 seconds. Still, 2 seconds seems to be a conventional amount of time. I think that Harry Potter was an exception because Warner Bros is so well associated with it.

So therefore, I have concluded from this short research that the logo(s) should take no more than 3 seconds, preferably 2 seconds, and the preview green screen should always take 5 seconds.