How is H264 interlaced handled?

I get 25p i general, no interlaced from camera. I can run 50p on one camera but have not tried that, but will probably use to get smooth slo-mo at some point.

So I get normal H264 with predictive frames or the Canon All-I that is just H264 I-frames all the way as I understand it.

I render for AVCHD only, either on DVD or memory stick of some sort.

All is 1920x1080. Large majority currently is time-lapse, but will be normal video shooting later too at some point.

In some editors I can choose whatever at rendering, progressive or interlaced.

Since I can only select 23.97, 25 or 29.97 progressive in PRE I have tested in other editors to select interlaced 50 fps and like that better especially if doing pan with video. Anything else than camera do, 25 fps, always get some anomalies in movement.

Don't know if AVCHD put restrictions on bandwidth, not quite like bluray as I understand it.

I think you only get 24-30 fps progressive, or 50-60 fps interlaced.

I am experimenting a lot to learn what gives what result, both shooting and editing wise.

And in the end on Vimeo will test what they do to the matter - when I know how it works offline - and what give best results.

So now trying to figure out how H264 works if doing interlaced - will it try to encode odd and even lines separately as two different frames?

Or is it players job to double framerate if interlaced, and pick in two sets of lines/rows - and full frame is encoded once?