How can I hide just part of the screen?

Peyton-Todd wrote on 7/12/2005, 4:39 PM
Hello. I have video clips of a hearing child of deaf parents learning to speak. On some occasions, he says his own name, and I need to disguise that to protect his identity. I have sound-editing software (a shareware product for linguists) which can mask everything but the pitch of his voice so that takes care of the audio. What I want for the video is just to hide his mouth as he speaks, since it would be easy to read his lips, but I don't want to degrade the rest of the picture.

After playing around for a good while with Vegas effects, the best I have found is the following, neither of which is satisfactory:

1. Pixelation - This hides his lips okay, but degrades the whole picture. Same with the blur effects. Is there no way just to pixelate a selected part of the screen? We see this all the time on TV (e.g., the private parts of a nude person pixelated out, but the rest of the image left intact.)

2. Swirl - This can be limited to a small area, but it looks tacky. Pixelation is a well established 'language' for this sort of thing. The swirl is unfamiliar to people and will look sort of strange.

Any ideas? It doesn't HAVE to be pixelation - just a black rectangle might do, since that's another commonly used technique. Or something else limited to a local part of the screen but not wierd-looking like the swirl.

Any help will be greatly appreciated!

Peyton Todd

Comments

Spot|DSE wrote on 7/12/2005, 4:48 PM
1. Pixelation - This hides his lips okay, but degrades the whole picture. Same with the blur effects. Is there no way just to pixelate a selected part of the screen? We see this all the time on TV (e.g., the private parts of a nude person pixelated out, but the rest of the image left intact.)
http://www.vasst.com/search.aspx?text=cops

2. Swirl - This can be limited to a small area, but it looks
GaryKleiner wrote on 7/12/2005, 4:49 PM
Duplicate the video track, and on the top one, add the cookie cutter filter where you can define the cutout. On the bottom track apply your blur, mosaic, or whatever.

Gary
Peyton-Todd wrote on 7/12/2005, 9:34 PM
Thanks, Spot (and Gary). I'm beginning to get the hang of it. Some questions remain, though:

1. Suppose you want the pixelation, or the voice distortion, to cover only part of the clip (in my case, the part where he utters his name)... is there a way to do that?

2. I'm guessing that the cops demo you mentioned at vasst.com may know how to do that, since they talk about following the perp. Is that right? But when I downloaded it, it only gave me the .veg file, not the video it goes with. Or do I need that? For now, I can't test it anyway since when I try to load it, it complains that my version of Vegas (3.0) is not high enough.

3. So far, the pitch changing method you mentioned has led to no effect. I also tried those keys while holding the Shift and Ctrl keys, but still no luck. I presume the track in question has to be selected for it to work. Is that right?

Thanks for your help.

Peyton
GaryKleiner wrote on 7/12/2005, 10:06 PM
1: You can isolate when the effect happens either by keyframing the cookie cutter, or by having the video event on the top only exist where you want the effect (e.g. cut away the rest).

3:To pitch shift, you must select the event.

Gary
Spot|DSE wrote on 7/12/2005, 10:08 PM
The track doesn't need to be selected, only the event. So, where you want to disguise it, then you'd simply make splits around that area, and make the duplicate around that area. Be sure it's the keyboard keys, not the NumPad keys that you're using.

From the help file:
Editing from the timeline
Select an event.

Use the = and - keys on your keyboard (not the numeric keypad) to adjust pitch:

Key
Result

=
Raise pitch one semitone.

Ctrl+=
Raise pitch one cent.

Shift+=
Raise pitch one octave.

Ctrl+Shift+=
Reset pitch.

-
Lower pitch one semitone.

Ctrl+-
Lower pitch one cent.

Shift+-
Lower pitch one octave.

Ctrl+Shift+-
Reset pitch.

To make the COPS effect be in place for only a single word, then just make the duplicate (in the veg I sent you) the length of the word, and if you want it smooth, create a short fade in, and short fade out, for the length of necessary time.
HTH
Peyton-Todd wrote on 7/12/2005, 11:00 PM
Thanks, guys, I managed to figure out a different way, I think, by selecting only the event of interest when I apply the cookie cutter or pixelating effect. But I still can't make the pitch-changing thing work. I assume I'm selecting the event properly: I double-click it, and it gets highlighted in blue, and then when I hit space bar that's the only part that plays. That means I have it selected, right? But I can hit Shift = 100 times and there is no perceptible change in the audio. Could that be a feature that doesn't exist in version 3.0?

Also, Spot (HTH), I never got the file you sent. Where should I look for it? It's not in my regular e-mail (peytontodd@mindspring.com), and I see no attachment to your posted reply.

Thirdly, another problem: Right now, since I haven't got your sound trick to work, I'm just deleting the audio where he says his own name. Earlier I got it to work, but I can't repeat what I did - whenever I select that portion and hit Delete - whether in the right-click menu or by pressing the Delete key - not only the sound goes away, but also that section of the VIDEO in the duplicated video track I made for the cookie cut. This still happens when I have the two video tracks 'silenced' and the sound exclamation pointed.

Peyton
PeterWright wrote on 7/12/2005, 11:39 PM
Make sure you have the audio event selected, and not the video.

(edit) - and you are using V5 or V6? I don't think V4 had this function.
typo wrote on 7/13/2005, 1:46 PM
Spot,


what happened in this thread? Truncated reply?

Ooops, I can see the thread got redirected to Gary's site. That explains it...
Peyton-Todd wrote on 7/15/2005, 10:56 AM
If you please... who's Gary, and where's his site?
Liam_Vegas wrote on 7/15/2005, 11:08 AM
enough already..... take this stuff somewhere else will ya!
GlennChan wrote on 7/15/2005, 12:05 PM
For the video portion, you can simply do a cutaway to something else. i.e. a shot of his hands, his parents, you the interviewer nodding, or some picture that matches what the kid is saying.

This would avoid any distractions from doing a COPS effect on the kid's mouth.