DVX-100: Firewire output dark

B

Bradford

Member
The capture to mpg (or Premiere Pro, etc. for that matter) is always much darker than what I'm seeing on my DVX-100 LCD screen...and *substantially* darker than what the analog (S-Vid, etc.) outputs put out, which is bright, but washed out and degraded, not surprisingly. As far as I know, the settings are pretty much default, and I suspect it's an inherent feature of DV videography, but I'm stumped.

I need to direct firewire capture my footage to mpg for CD-ROM distribution without having to edit the brightness/contrast, or lose quality by using the analog outs.

Any suggestions? None of the firewire capture software packages that I've seen offer any brightness/contrast adjustment during capture. And why is the firewire output so much darker than the camera LCD and the analog outs?

Thanks!
 
Re: DVX-100: Firewire output dark

It shouldn't be. Firewire represents the actual data that's recorded. The LCD might be showing too bright, sure... but that would be because the LCD's brightness might be cranked up.

If you're viewing the firewire footage on a computer monitor, and the s-video footage on a television, then that might be the explanation right there. Computer monitors are darker than televisions -- they have different gamma and display footage differently, and everything always looks darker on a computer than it does on a television.

There should be no brightness difference between the firewire footage and the s-video footage, when both are played on the same television. Try capturing the firewire footage onto the computer and burning a DVD directly of it. That should result in footage with the same brightness as if you'd plugged the camera directly into the television and played it from there.
 
Re: DVX-100: Firewire output dark

Thanks for the quick response!

I checked, and it doesn't seem that the DVX-100 LCD brightness or contrast is above normal/default...or that the (Sony 15" LCD) computer monitor is set below average/default on brightness/comntrast. I notice the same behavior with my Sony DV handycam as well, BTW... I'm familiar with the idea that output on a computer screen (particluarly LCDs, I think) would be darker than similar content output on a TV...but it's confouding that it's so much darker than the DVX LCD (or my DV handycam LCD). Incidentally, I *do* notice that when edited DV footage is re-output to either DV camcorder, the camcorder LCD display of the footage is again substantially brighter than the program window on the computer monitor...back to the way it looked on the camcorder LCD to begin with.

None of that probably surprises you, I'm guessing...but let me lay out the key questions/problems behind my original question:

Should I have to "dial down" the LCD on the DVX-100 (or any other DV camcorder) to get an accurate idea of what the footage will look like when it's dumped over to the computer?

Also, given that my "day gig" requires outputting to a VHS deck running tape via the analog outputs while recording to the DV tape, is there any way to reconcile the difference, absent any brightness/contrast input controls on the VCR? (BTW, DV Rack wouldn't really be an option unless it allows live mpg capture...even if the DV signal could be tweaked via software, we can't re-render hours of footage to mpg)

Hope I haven't made the whole thing more convoluted, but that's our dilemma.

Thanks again for your help!
 
Re: DVX-100: Firewire output dark

[quote author=Bradford link=board=Events;num=1097277395;start=0#2 date=10/08/04 at 19:32:17]

Should I have to "dial down" the LCD on the DVX-100 (or any other DV camcorder) to get an accurate idea of what the footage will look like when it's dumped over to the computer?[/quote]
Well, the answer to that question is: do you want the video to be viewed on a TV or on the computer? If it's designed to be viewed on the computer (i.e., web streaming video, etc), then yes, adjust the LCD so you have a better idea of what you're getting. But if the video is destined for a television, then definitely don't modify your LCD to match the computer, because the computer display is irrelevant. What's important is how it looks on a TV. So you'd adjust the LCD so it displays what the footage would look like on a TV.
Also, given that my "day gig" requires outputting to a VHS deck running tape via the analog outputs while recording to the DV tape, is there any way to reconcile the difference, absent any brightness/contrast input controls on the VCR?
Click to expand...
Well, I'm not really following you. All I can say is, if you're making it for video release, the computer screen *will* be darker, and that's really irrelevant: what you need to monitor is how it looks on a television. You most definitely do not want to be modifying your signal to look better on a computer monitor, if it's destined for TV release.
 
Re: DVX-100: Firewire output dark

Ack! Wrote a lengthy post last night and lost it before posting...grrr

Anyway, thanks... I don't think it's a setup issue. Apparently, I've just gotten used to using the DV cam for monitoring on personal projects, and the "flat" look of native DV on the computer LCD is now throwing me off.

Unfortunately, the word "release" doesn't figure into either my day gig or personal video efforts at this point. We *are*, however, required to make and file a VHS copy of footage made simultaneously (via analog outs) while DV taping. I guess I will just let the file copy be nasty bright and optimize for computer output.

The DV Rack trial package has been very instructive, as far as instantly seeing the native compressed DV look. It sure does look washed-out compared to what I would hope to record. Is this aggravated by the 4:1:1 scheme?

Any suggestions on how to get a more (I guess) saturated, bright and contrasty (and to my eye, "real") look to the raw DV footage (as seen on the computer, being the final platform), so less tweaking is required later...? I assume if I decide to also output to DVD, etc. for TV NTSC viewing, I can correct the video at the final stage.

Also, is it normal for the analog outs on the DVX-100 to be way brighter than the DV out? In this case, I looked at *both* on the computer LCD. I tested 3 different analog-to mpeg converters, including plextor and the more expensive MpeGator PCI card - and in every case, the look was much brighter/saturated/contrasty than the direct DV (firewire) transfer...and of course, degraded, being analog and highly compressed. If I did a direct DV encode to mpeg, though, it was as flat and dark as the DV avi.

Even if there is a 7.5% setup on the analog outs, it wouldn't seem to explain this much of a difference.

FYI, I'm certain that unless the camera is messed up, the settings should be standard. 60i, white-balanced, Scene F1 (re-initialized, just to make sure)... I see no setting to affect the DV or analog outs *separately* in terms of gamma, saturation, etc...

??[puzzled]??

Thanks again!
 
Re: DVX-100: Firewire output dark

I use final cut express on my mac and so I run a firewire cable from my camera to the computer and it always looks a little darker than it does on a tv, so I just have to edit knowing it will look a little different.

Lol.!!!
 
Re: DVX-100: Firewire output dark

Bradford, I don't think it's your setup. I have experienced the same effect. If your video card has a TV-out, you can hook up a TV or (ideally) an NTSC monitor and drag your video capture window to that display. This will allow you to see (approximately) how the final output will look. Takes a lot of the guesswork out of the equation when manipulating levels, as well. Good luck!
 
Re: DVX-100: Firewire output dark

Hmmm. My laptops do have S-Vid out. I don't know if any of the software apps (other than DV Rack) allow you to capture while actually shooting (i.e., capture from the camera while recording to DV tape)...do they? I have Premiere...I think I tested it and couldn't do that.

I've learned so much lately that I think I'm getting *re*-confused...lol... I'm starting to get an idea, though...please correct me if I'm wrong:

Camcorders output from 7.5-110 (or whatever the upper end is) IRE, or 0-(whatever) IRE if the setup is at zero. This, I gather, corresponds to DV stream values of 16-235. Computer screens, though (and editing software and avi files, mpgs, and whatnot) can utilize and display a range of 0-255...right? So it seems to me that if the *primary* output will be for CD-ROM or web distribution, we should be expanding the dymanic range of the DV footage (*especially* if we're going to combine it with computer-generated graphics)...so that we'll have a richer-looking video with dark blacks and bright whites for people viewing on computer screens...

...and then we could re-adjust if we need to output to DVD or other NTSC-compatible formats that will be viewed on TV...?

Am I on the right track here? And if I am, should an NTSC-friendly luminance range be used for the new LCD and plasma screens, or will they display a color range similar to computer monitors...?
 
Re: DVX-100: Firewire output dark

Incidentally, after checking out the link in Andre's post, it appears that the Black Level Setup on the DVX-100 *does* actually affect the DV stream...not just the analog outs.
 
Re: DVX-100: Firewire output dark

The black level setup does affect the DV stream, which is why you never want to use it.

There are two types of codecs out there, "clamping" and non-clamping (and assumedly you could probably configure your codec to be either variety). Clamping will compress the 0-255 range down to 16-235.

For most purposes you want your DVX set at setup 0, and edit as-is... you shouldn't be messing with brightness or contrast, as it should look just fine when displayed on a television. For CD-ROM or web streaming output, you would run a filter such as Vegas' "Studio to Computer RGB", which will correct the brightness, contrast and gamma to display properly on a regular computer monitor.
 
Re: DVX-100: Firewire output dark

Barry,

DV Rack shows 5, 7.5, and 9-ish IRE on the PLUGE portion of the DVX-100 color bars if I set the DVX's setup to 7.5...which sounds about right (superblack, black, grey)...and I suspect that equates to 16-235. If I leave the DVX-100 setup at 0, the PLUGE readings are shifted down to around 0...looks a little better to my eye on the computer, but it would appear that I've just shifted everything down 7.5 IRE from the "official" levels...possibly corresponding to 0-219...so should I leave the DVX-100 at 7.5...?

It definitely appears that the raw DV output from the DVX-100 (and apparently, from what I gather, any DV-compliant stream) is 16-235...is that not correct?

Also, are there any studio-to-RGB filters for Premiere Pro?

Thanks again,

Bradford
 
Re: DVX-100: Firewire output dark

Oops...I should have said, 5, 7.5 and 10 IRE...I was going from memory and forgot what the upper number was...All this DV stuff is making my head hurt...!
 
Re: DVX-100: Firewire output dark

Ah, geez...I thought I saw the whole thing on Setup, but I missed the DVX-100-specific Setup section...

Sorry - I *really* am trying to do my homework!
 
Re: DVX-100: Firewire output dark

Using the in-camera setup option lifts the black levels upon recording. The result is that you won't use the full dynamic range of the camera; it's actually a very similar result to raising the master pedestal.

Proper setup options would lift the black level on analog output, but would still record the full signal. Using the DVX's setup option modifies the recording as well, which wastes dynamic range.

If you're going for an analog output, your analog device should be adding the setup you need. But using the in-camera setup is causing the blacks to be recorded up at 16 instead of down at zero where they should be.
 
Re: DVX-100: Firewire output dark

I guess my last post didn't take....I found the DVX-100-specific section at adamwilt.com...I thought I had read everything there on Setup, but I missed that part. Sorry, I really have been trying to research everything as thoroughly as possible before posting...
 
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