Derek Steen, Viddler’s new Community Leader (djsteen), has put together a dead simple tutorial for deinterlacing videos before you upload them to video sharing sites, like Viddler. But, before you read that, you may want to know what interlacing and deinterlacing actually is.
Here is a quick excerpt from Wikipedia. If the quoted section isn’t enough for you, I recommend going to Wikipedia to read the full article.
"In footage shot by most television and video cameras (except more recent models which allow a non-interlaced mode), the two fields of a frame are taken at different times, which results in an effectively doubled time resolution as compared with non-interlaced footage, thus enhancing motion perception to the viewer. This remains one of the benefits of interlacing.
However its benefits can only be experienced if the display shows the individual fields in the same timely order they were shot in. At this time, only traditional CRT-based TV set are capable to do so. If correctly adjusted, they need not suffer from any interlacing artifacts, they even benefit from it.
Yet when the fields of the original footage are displayed in a different order than they were shot in (i.e. when two fields taken at different points in time are re-combined to a full frame displayed at once), visual defects called interlace artifacts or combing occur with moving objects in the image."
It is a long bit, sorry – but it does a fairly good job describing the cause and effect. Now that you know what it all means and why it should be done, run over to Derek’s site and read his tip so that you can save yourself the headache that interlacing can cause.
Source: Deinterlace your online videos.