Reduce brightness from Dark background(Video)

[riomarble]

Hi, I've been reading up on using various filters for virtualdub/avisynth for hours with no luck. I wanted to know if it's possible to reduce the brightness of the person as in the sample pic, so he can be visible instead of some light-dude. I don't care what programs to use to filter it. Please help me out! This is a video btw.

[DereX888]

This is a video btw.

[PICTURE REMOVED]

By "video" you mean the source is VHS?
If so, I'm afraid you're out of luck
(assuming this person is all the time just white blob in the center of the screen in your video)

/edit
And even if the source was some better digital video (as in DVD or DV or HDV) you probably couldn't do much, from what I see (if your screencap is correct) the center-stage person is really just an over-exposed white blob... If it were some higher resolution source (HDV, HDTV, BD etc) perhaps there would be more pixels than just white outlining of this person, but from VHS...

[riomarble]

It's an MJPG format from digicam. 640x480/30fps. So nothing can be done?

[DereX888]

It's an MJPG format from digicam. 640x480/30fps. So nothing can be done?

I don't know. It is really hard to say anything definitive from just a low quality screencap of a single frame.
Can you post the original frame's screencap or sequence of few "best"? (where you can see something more than just white blob)
- and without downgrading it with jpeg compression and reducing their size, pls

[edDV]

Nothing there to extract. The camera exposed for the curtain not the subject.

8 bit digital cameras have only 256 levels of gray. The spotlight got maybe 5 levels a the top?



This shot required manual exposure.

Stretching the light blob only gets you this.

[DereX888]

This shot required manual exposure.

Certainly.
(As usual) It was set on auto, and averaging the zones only over-exposed the dude.
If he was so important the cameraman should have zoomed, focus and set everything on his face, lock it, and then pan out and capture the whole stage.

[riomarble]

The thing I don't get is how come I saw clearly with my own eyes but not on the cam? I don't think my canon(A570IS) doesn't have Manual exposure; probably only on camera mode. Only thing I did was "Digital zoom" which sux, but that didn't change the brightness. If I were closer it would have been better? I'm kind of confused to how this works.

And please check my pm guys. Thanks!

[DereX888]

The thing I don't get is how come I saw clearly with my own eyes but not on the cam? I don't think my canon(A570IS) doesn't have Manual exposure; probably only on camera mode. Only thing I did was "Digital zoom" which sux, but that didn't change the brightness. If I were closer it would have been better? I'm kind of confused to how this works.

And please check my pm guys. Thanks!

Your eyes have much higher resolution than any existing cameras (yet)
Thats why you saw this person clearly, and your camera didn't.
Also the AI of most cameras use simple averaging of the screen zones when adjusting exposure (while your eyes don't work that way). In this simplistic automode the camera's AI decided the most of the picture is the background (the dark curtain) and it set the exposure accordingly - thus overexposing in the same time your brightly lit object on stage.


Yes I just read your PM.
Removing the pic now.
(however it will render this thread useless for anyone who'd read it in the future, so pls. next time don't post in public what you consider private )

[edDV]

Your eye has much wider exposure latitude vs. your camera. That shot needed to be stopped down several f stops. the only way to test it is to take the shot, evaluate from the LCD and correct up or down until you could see the subject.

To use auto exposure you would have walked to the stage under the same light, noted or locked the exposure, then walked back to your seat.

[riomarble]

The thing I don't get is how come I saw clearly with my own eyes but not on the cam? I don't think my canon(A570IS) doesn't have Manual exposure; probably only on camera mode. Only thing I did was "Digital zoom" which sux, but that didn't change the brightness. If I were closer it would have been better? I'm kind of confused to how this works.

And please check my pm guys. Thanks!

Your eyes have much higher resolution than any existing cameras (yet)
Thats why you saw this person clearly, and your camera didn't.
Also the AI of most cameras use simple averaging of the screen zones when adjusting exposure (while your eyes don't work that way). In this simplistic automode the camera's AI decided the most of the picture is the background (the dark curtain) and it set the exposure accordingly - thus overexposing in the same time your brightly lit object on stage.


Yes I just read your PM.
Removing the pic now.
(however it will render this thread useless for anyone who'd read it in the future, so pls. next time don't post in public what you consider private )

I see. There was 1 option which was AWB(including manual). But I'm assuming that doesn't do anything in this case?

[DereX888]

If you only have digital zoom (or you were still too far for the optical zoom) and you only have auto mode there, the only thing left to do was to come up as close as you could and lock it on the dude.
Best of course would have been manual exposure/aperture setting.
I'm also almost sure if you read your cam's manual you'll find that at least aperture can be manually changed there...

Also, you should have seen the person on stage exactly as white blob on the screen of your camera when you were recording it (assuming it were you). The digital camera's displays are always "what you see is what you get" type.
You saw white blob on your cam's display, didn't you? (thus you should've known right there that there is something wrong with the settings - unless you thought you can "fix it later on the computer", an often and very common assumption/mistake, actually)

(AWB probably is Auto White Balance, it wouldn't help - it only adjust your camera to the type of the light it sees, so i.e. picture taken under sunlight is not yellowish or reddish, and picture taken under cold artificial light is not blueish, and so on)