V-Dub Filters - How Do I Apply to Limited Segments of Files?

[Zeek]

Hello all, and hope this is the right section to post this question in.

I have some videos from my wedding that I'd like to modify slightly using V-dub filters and am running into a problem I've not really had to deal with before. Basically, I'd like to apply some filters here and there on the footage, but want them to be applicable only to specific segments and not the whole file. (For example, color is fine for most of the video, but kind of weak at certain points and I'd obviously like to adjust saturation in those areas only.)

I do have some limited experience with V-dub and getting the filters in there is simple enough, so no problems there. However, what I would like to do and seem unable to do so far, is select a segment of video and apply filters to it, have V-dub do its thing, and then save the (newly modified) file with changes made so that I am done in one step.

It's no problem, of course, to pull a section out here and there, modify it, and then re-insert it later, I guess...but this seems like more hassle than it should be - especially considering the potential overlap/gap issues there would be if a mistake were made when pasting the sucker back in.

Is there an easier way? So far, what I've been doing is selecting the frames I want to work with, applying filters, and doing the usual "save as". Works great...except what I'm saving is only the segment containing the selected frames and not the whole file, as I would like. This hasn't really been an issue for me in the past because, on the rare occasions that I've needed to filter, I've never really had the need to apply filters to anything but the entire file. So, if anyone can shed some light on this, I'd be much obliged...

Thanks, and sorry for the long post...

Zeek

[mats.hogberg]

Well, some filters have their own "on" and "off" frame setting (like at least one of the logo filters) but if that's not available in the filter, cutting up the AVI in pieces, filter the parts you want, piece it back together again seems like the only way to do it.

/Mats

[Zeek]

Thanks, man. I figured that would end up being the case. Just hoped I might get lucky and find an easier way.

[Zeek]

Actually, for anyone else that might care, there is a guy who has come up with conditional filters for V-Dub that will let you modify only a part of any given video. Check it out here .[/url]

[mats.hogberg]

If it does what I think it does (and does it well), it sure is a great contribution to VDub abilities.

/Mats

[Zeek]

Hmmm....

Update: Just finished the first test-drive of it and, visually speaking, it certainly did the job. However, the original test file was around 5GB and the resultant one ended up being 44 or so. Why I have no idea, but I don't remember this ever happening to me before when just using "normal" V-dub filters.

The author says his filter is actually not a real filter in and of itself. Instead, it simply makes possible the conditional use of already existing V-Dub filters to a section of whatever video you're working with.

I used only his filter and the hsv one...increased saturation to 200% on one particularly not-so-well lit area of my video. Saved the new file separately as usual, and obviously had to work using full processing mode. The result looks great, but the file size is obviously not going to work for me. Coud it be that bumping the saturation up like that requires that much more information?

I will try experimenting with it a bit on Monday (maybe increase saturation less, try it without this new filter, try other filters, etc) and post what I find. Hopefully it is tweakable.

Z

[ZippyP.]

Saved the new file separately as usual, and obviously had to work using full processing mode.

You need to select some type of compression before saving or Vdub will default to uncompressed. If you ulitimately are converting to mpeg then you might want to frameserve the video to your encoder. This means no saving to an intermediate file and no extra compression stage. Look in the "Edit" section under frameserving over there <-<-<-.

[Zeek]

@Zippyp:

Thanks and yeah, I will definitely check out the guides. I've messed around a little bit with the frameserve toys in the past and know that it saves a step, but definitely would not say that I fully understand how it does this. I have a dual Xeon machine and the usual procedure is to do it the long way...."capturing" as .avi using camcorder pass-through, editing in V-dub, and then encoding to MPEG2 before authoring up the final (DVD) product. With the extra processing power, I've always figured there was little harm in doing it the long way, since I know exactly what I'm doing with this method - but it would be nice to save the time and that extra step by doing it your way.

Also, about the "uncompressed" default setting: Whenever possible, I try to use direct stream copy to avoid exactly what is happening to my file sizes here. Since I'm editing, that's obviously not an option...but there is more than one option among my alternatives. I've read a little here and there on normal vs fast recompress, but frankly haven't found too much in the way of a real explanation of the pluses and minuses of each. Which would you suggest I use? And as for compression, do you have a recommendation for codec? Since I'm going to be encoding again to MPEG2, I'd like to mess with whatever I'm going to mess with as little as possible to preserve quality.

Thanks...

[Zeek]

Problems solved. I usually find my way there by reading the guides (did this time, too), but I wouldn't have found this one this quickly without the pointers.

Thanks guys.