Is it possible to soften MPEG-2 video?

[nullinvoid]

I've got a DVD that I'm doing some improved subtitles for, but the video on it is really second-rate--it looks like someone ran a sharpen filter on it before encoding. Currently the video is in .m2v format since I'm working with it in DVDMaestro. What I'm wondering is if there is a utility that would apply a soften filter to the video without having to convert it into another format and re-encode it as MPEG-2--unless there's a way to do that without damaging the quality.

Thanks,
Nullinvoid

[theReal]

You must reencode it to mpeg2 unless you want to use a filter that is applied while you're watching the video (if there is a post processing filter like this, I don't know).

If you want to apply filters to compressed video, you always must decode and reencode and therefore lose quality.

[Kedirekin]

I agree with theReal that you must re-encode to get the change you want. However, I don't agree that you can't improve quality. I sometimes think the picture studio tells the DVD production studio they can only encode the movie once, and that's what ends up on the DVD, crappy or not.

Okay, to be fair, most of the really bad encodes I've seen are on older movies (1990 and older). The fact that the quality of original production wasn't up to today's standards and the passage of time both probably have something to do with the poor quality.

Anyway, in my opinion and experience, use of BilinearResize (and optionally judicious use of the vDub SmartSmoother filter) can produces substantial improvements in video quality.

[theReal]

OK, I also agree: the crappier the movie, the more quality you can gain by re-encoding with some filters applied. But if it's only a little grainy, I think it's hard to improve quality because you lose more than you gain on the re-encode.

nullinvoid, you could just try to apply some avisynth filters and re-encode on the fly to mpeg2. Maybe you like what you get, maybe not...
I don't know however what mpeg2 encoder would be best. The best one I know is Tmpeg, but that doesn't mean anything because I usually never encode to mpeg2.

btw. I don't think Bilinear Resize would be of any good here because you want to keep the DVD format and therefore keep the resolution.

[nullinvoid]

Sounds good. Thanks for all the advice. I'll try running some filters and see what happens when I re-encode.