Deinterlace Created Dec 20, 2009

Deinterlacing is best done at the hardware level, which is (for example) what happens on most machines when you play an MPEG-2 based DVD on a computer.

Next best is to re-encode the video as progressive. Different videos need different deinterlacing settings (odd, even, interpolate, duplicate, etc.) so even if you were to compose a Flash video player that uses a convolution filter the results will be marginal unless you hand-tweak the settings for each video. And even then, anyone with a "CPU-deprived" machine may not enjoy video playback much because of the extra processing required.

If you are providing a live feed then simply remove the interlacing at the hardware processing the encoding.

If you're converting interlaced video apply it via software.

If you're trying to deinterlaced already converted FLVs or MPEGs then it's too late. The interlace artifacts are already a part of the video and adequately removing them is difficult and generally not worth the loss. Go back to the interlaced source.

A great guide from here, hope it can help you.
http://www.my-video-converter.com/deinterlace_video_remove_interlaces/