Sorry if this is a simple question but I've nto managed to find anything which quite answers my question so far.

If I record something in 1080/50i and I wasn a progressive/deinterlaced version to run on a laptop at exactly half the resolution (so 540 pixles high) do I de interlace the original and then resize or do I resize then deinterlace or infact if I just resize by 50% does it just drop automatically to 25p by dropping half the lines anyway?

TIA
Chris