Question about De-Interlace Settings

[m021478]

Could enabling the 'de-interlace' setting for ripping a disc that doesn't necessarily need de-interlacing hurt the final output quality of a converted video in any way? (FYI: I am using the Mac application 'Handbrake' for my ripping needs)...

I only ask because in the past, there have been times that I'd chosen not to de-interlance some movies because doing an A>B comparison of the with/without preview of the movie yielded no disernable differences, and once the rip was complete, it was clear that I should have had de-interlacing enabled, as the horizontal distortion lines we more than evident...

So my thoughts were that if it doesn't hurt the final output in anyway, then I should just keep it enabled for all rips just to be sure...

I tried doing a comparison of the preview with/without 'de-interlace' enabled on a movie which I know didn't need it, and it appears that it might have the effect of ever-so-slightly blurring the video...but my eyesight isn't good enough to make a final call on this theory...

Can anyone give me the skinny on the de-interlace settings regarding its effect on movies that don't 'need' it? Thanks!

[zoobie]

general theory here is to leave it interlaced for best quality
comblines are only seen on a computer screen

[m021478]

Does adding de-interlacing to a disc that doesn't necessarily need it blur the output at all?

[Crus7y]

Yes, it does. The kind of blurring depends on the deinterlace method.

[m021478]

I am using Handbrake do perform the de-interlacing...any idea what kind that app uses, and if it causes blurring?

Should I simply rely on the on-screen-preview of the with/without de-interlacing filter effect to determine whether or not to use it for a particular disc?