Sony Dig 8 Pass-Thru Question about faded transfer

B.Verlik wrote on 3/12/2005, 8:45 PM
Faded is not really the right word. I tried transfering VHS tapes and a Satellite signal through my Sony TRV 730 and the results remind me of what has happened to me when I try to cover 'News scrolls' with big Black Bars. (Text blown up to 900). What happens is that the video looks like it has a whitish filter over the whole picture, a look similar to the contrast being turned down, except it almost looks a little whiter. Is this normal for 'Pass-thru'? I hate to think that my "datavideo DAC-100" A/D converter, gets a more natural looking transfer.
Is there an easy fix for this? I did try using the search here, but as usual, I must have requested using the wrong phrase. (I know somewhere here, a few weeks ago, I heard that adjusting the contrast was the wrong way to go about this, but I forgot where I saw this.)
Thanks in advance.

Comments

Spot|DSE wrote on 3/12/2005, 10:07 PM
You'll want to use Curves to repair the currently captured video, but if the camera is truly passing the vid through, there is something else not correct, or else the footage is actually problematic. You sure you have good cables? Anything in a menu somewhere on the Dig 8?
B.Verlik wrote on 3/13/2005, 12:03 AM
Thanks for answering, Spot. I don't think that there's anything in the menu, but I did change the brightness of the playback in the little swivel monitor attached to the camera. To be honest, I didn't even consider a control in the menu that would affect pass-thru in that manner. But I know I looked at all those functions and don't remember anything except TBC and DNR It seems like the video I"ve transfered from the tapes recorded on it, looks normal. And I did sort of correct the transfered VHS and the live Satellite recordings, using the Contrast, but it seems like this adjustment was touched upon, just a few weeks ago, and I can't remember what the subject was. (wasn't Pass thru), but they said that the Contrast was the wrong way to go to correct this.
I just looked at the menu again. Nothing obvious there. I hope DNR doesn't cause this. If it's an easy fix, I won't complain too much. (I'm so crowded here, that I can't have the TV hooked up to the output of Vegas to fix things. At least not yet. It aleady looks like a fire hazard of cables laying all over the place.)
I hate to admit it, but 'Curves' doesn't tell me enough. This must be a Vegas 5 thing. Maybe that's why I can't remember where I read this at. Unfortunately, I'm still on Vegas 4d
The camera seems to work in every other way (bought it used just a month or so ago). I hope this isn't a broken feature. But if I can correct it (and I'm sure I can), I'll be okay with it for now.
I guess I was hoping somebody would say, "Hey just turn off this do-hickey".
farss wrote on 3/13/2005, 4:21 AM
There's nothing in a D8 camera that'll change the vision levels. I've transferred probably 1000s of hours of VHS through my D8 camera and an ADVC-300 and never had this problem, in fact on some footage the D8 does a better job than the 300.
DSE was referring to the Color Curves, they're in V5, you should look into them, very usefull. Also don't trust your eyes too much, look at the scopes, on the histograms your video should go from around 10 to at least over 200, most Sony DV cameras will run upto 255.
Bob.
B.Verlik wrote on 3/13/2005, 1:46 PM
Thanks Bob. I was afraid of that. That means that it's the pass-thru that's messed up somehow. I wonder if there is an internal adjustment that's not obvious to the layperson. It looks fairly normal, but as I said, as if someone laid a white filter over the entire picture. Although, I didn't notice this on the tapes I recorded on the camera and then transfered to PC
It'd be nice if a real Sony person could jump in with that answer. (that is, if you know)
Spot|DSE wrote on 3/13/2005, 2:03 PM
I somewhat doubt a Sony person in these forums could comment on the camera, simply because they're different divisions.
Whatever happens to the image HAS to be happening in the pass-thru, because Firewire and VidCap are not capable of being responsible for changing the colors in the datastream. Whatever is coming off the Digi8 is what the Capture app is seeing.
jaegersing wrote on 3/13/2005, 7:33 PM
There isn't a switch somewhere for setup by any chance? I know that Japanese NTSC DV does not use setup, but USA NTSC DV does. If your VHS player is outputting video with setup and your Sony cam is expecting video without setup, I imagine you would see a similar effect to what you describe.

Just a thought.

Richard Hunter

johnmeyer wrote on 3/13/2005, 11:06 PM
Are you capturing this using Vegas' capture? If you are using some other program, the video could be captured using a codec that may have the 16-235 to 0-255 mapping issue, and this can cause washed out video like you describe. However if you use this workflow:

VHS composite output (or S-Video) --->

    Digital8 camcorder input -->

        Firewire output (not USB) -->

            Firewire input on computer -->

                Vegas capture
you should have none of the artifacts you are talking about.
farss wrote on 3/13/2005, 11:21 PM
I'd imagine that's how it's being done, I don't know of any D8 cameras that do video over USB.
Apart from the possibility of a setuo issue I've still not seen any analysis based on actual measurements, those nice guys in Madison gave us wonderful tools to work with and we don't use them, shame!
Anyway, one thing that could be happening, the levels on the VHS could be a bit over the top, this was fairly common in the heyday of VHS, now when this outside legal video goes into the A->D converter it gets clamped which will make it look kindof washed out but until the Gr8 looks at it with his scopes it's really hard to know what's going on.
And there's nothing inside the camera that'll enable you to change any of the conversion settings apart from turning off TBC and DNR. What has me confused is I think it was said that recording to tape and capturing that back gives a different result from just doing a pass through, that sounds very odd to me, what is written to the tape is the same as what the A->D converter would send straight to Vegas in pass through.
Bob.
B.Verlik wrote on 3/13/2005, 11:30 PM
I don't know exactly what you mean and yet I get a feeling you may be on to something. Do you mean if my VHS player has TBC and the camera has TBC switched on, that both together may cause the problem to take place?
Or if the VHS machine has a special "Copy tape" switch (and it does) and it and the Dig 8's camera's TBC and DNR combined may cause this?
I'm sorry but the term 'setup' isn't registering for me in this situation. The only other switch that deals with this is the A/V >DV Out On or Off. And that's on. The camera is model TRV 730, pretty sure it's NTSC (or I couldn't watch it) and it's does say 'Made in Japan' on it. But I don't know what you mean by the term 'setup'. Unless 'setup' is the same as the 'copy tape' switch. (which is on a JVC S-VHS deck I use for playback of tapes.) I don't understand why the S-video feed from the satellite box would cause this then too. (unless I should turn off the TBC or DNR.) I'm stumped.

Thanks for all the responses so far........
B.Verlik wrote on 3/13/2005, 11:34 PM
To johnmeyer and farss, you answered while I was answering the one above you.
Yes, John, I hooked up as you listed.
Now I'll post this before it lags behind to much and read the other again.
B.Verlik wrote on 3/13/2005, 11:53 PM
Mine has a USB port, but I have no interest in using that either (and am not even sure what it's for. The photo or mpeg capabilities???). Ironically, these VHS tapes were just recorded a year ago on a Sony VHS machine. The Satellite feed, I recorded, was right out of the S-video jack. And I do have a habit of covering logos and scolls with black text patches, which in my experience also causes the whitish look. (no, I'm not fooling anybody, I just don't like distractions and with 'channel logos', 'upcoming promotions' and other scrolls, I get rid of them by simply covering them up with gigantic black text hyphens) It doesn't look great but it does the job and this isn't anything important, just some old tv shows I wanted to save.
As far as what I recorded on tape and transfered. It was sketchy material to use as an example and I need to retest. But it was recorded by the camera, not the pass thru feature. Nevertheless, I need more tests. I'm just so short of room to work and the time to experiment. I was hoping for an easy fix, but instead I wasted more time looking for easy fixes.
Boy...what if the camera just does this to everything? YEEOOOOWWW!
jaegersing wrote on 3/14/2005, 7:08 PM
Setup is used in NTSC video signals, to force the black level to at least 7.5IRE. If the VHS deck is adding setup, and the camcorder is not removing that setup before converting to DV, this would be similar to a shift in the brightness of the video signal.

Richard
cbrillow wrote on 3/14/2005, 7:52 PM
Gr8Steve,

A few comments -- some factual, some opinon/guesswork:

I have a DCR-TRV350 which I regularly use for pass-through.

1) It is capable of USB-2 video transfer, but not full-frame DV. For that, I use the firewire port. The manual and most forums consense that the USB port is intended to stream low-res video to your PC, allowing you to use the camcorder as a webcam, if you like. (I DON'T LIKE...) My camera came with software from Pixela which also permits capturing the video in a limited number of formats from the USB port.

2) Adjusting the brightness of your LCD preview screen has no effect on the video spit out through the firewire pipe.

3) I believe the manual states that DNR is only operational when playing back HI-8 or regular 8mm tapes, which seems to imply that it also has no effect on pass-through.

4) The manual is unclear (at least, to me...) whether this also holds true with TBC, but I firmly believe that TBC works, and works well, during pass-through. As one of the other posters has mentioned, passthrough, in some cases, can appear to be superior to video coming from dedicated devices, such as the Canopus ADVD-100 & ADVC-300. This, of course is subjective, so please don't anyone start an argument calling me crazy for making that claim. I can cite, as anecdotal evidence, the experience of an owner of BOTH Canopus devices mentioned, who went out and bought a Sony camcorder specifically for pass-through after I let him use mine to capture a VHS tape through it.

I've read all the posts in this thread, but quickly. I'm wondering if you've tried shooting video on your camera, and then transferring to your computer to see if you obtain similar results? If you do that and don't see the white cast, it might add weight to your theory that there's something amiss in the A./D pass-through section. You might further reinforce this notion by using your camera in VCR mode and actually record the video coming from your VHS source, then spitting it out via firewire to the PC.

If you can shoot a video that turns out as you expect, but can't record or pass-through without the whiteness, it would strongly suggest that something's wrong with the A/D.
Catwell wrote on 3/14/2005, 8:15 PM
I am probably way off base here, but your description sounds like an unterminated signal. I don't know how this could occur in the setup you have described but if the composite signal does not see a 75 ohm termination, the picture will be badly washed out.
johnmeyer wrote on 3/14/2005, 8:37 PM
Try capturing VHS, via the analog input, directly to your tape. Then, play that tape, from the camera, back through the analog output, to your TV set. How does it look?

If it looks good, then I go back to my theory that somehow your capture setup is using something other than the Sony DV codec. You can check this. Put some video from your analog captures on the Vegas timeline. Right-click on the event and look at properties. On the Media tab, what sort of Attributes and Format are listed?
B.Verlik wrote on 3/15/2005, 12:45 AM
Wow! I thought this was dead in the water. There's two possibilities, that I see. 1. That this 'setup' thing that Richard (jaegersing) mentioned, sounds like the problem. Except that my old JVC S-VHS (HR-S7300U) machine doesn't have that term (setup for pass thru) in the menu or manual. Looking at the manual, there is something called "Dynamic Contrast". Only description: Use this function to improve contrast which tends to degrade specially with wide-screen pictures. There is also a switch in the menu called "Tape Dub Mode". Without stating what this switch does, the manual says it should be on if you are playing back or recording a tape and dubbing to or from another machine. The only other statement is that "Dynamic Contrast" and "Tape Dub Mode" cannot be engaged at the same time. The "Dymanic Contrast" has never been used. I never checked the "Tape Dub Mode" when I made the transfer, as I never noticed any difference before, when dubbing tapes. I use this deck because I can use the S-video output before A/D conversion. But this is also how I recorded to my elcheapo 'DAC-100 by datavideo' A/D converter, and it worked fine that way.
2. I can skip #2. I thought maybe the camera was recording tapes this way too. Originally, when I got this camera, I merely tested it enough to make sure it worked and viewed everything back in the little swivel monitor on the camera. It seemed ok that way. But the only thing I had saved, when I asked about this, was a silly recording I made of my computer screen of me and my brother playing video golf on the internet, where we could design our own characters. (TW2k5) This video was not sharply focused and just looked a little funny, so I wasn't sure. But some new footage has confirmed that the camera seems to record fine. WHEW!!!!! So this seems to be an issue with the JVC S-VHS machine playback and the pass-thru feature. Or just the pass-thru feature. Or those stupid 'text' objects I use to cover logos and scrolls. (and those do seem to enhance the problem)
Yes, johnmeyer, I checked the properties and they are normal. Although I haven't yet tried transfering to tape and then to the PC.
So, now I'll need to start experimenting with some more transfers using the pass-thru feature and that may take me a day or two. (gotta make time.)
Thanks for trying, guys. I appreciate the effort.
farss wrote on 3/15/2005, 1:26 AM
Arrrgh,
man why don't you look at the thing with the Vegas scopes, they'll most likely tell you straight away what's going on.
If you want to get really fancy record some bars to VHS or pluge and see what it ends up aswhen it's transferred back into Vegas.
Bob.
B.Verlik wrote on 3/15/2005, 2:21 AM
Sorry Bob. I keep evading the issue because I'm too embarrassed to say I've never used them before. I may have mentioned in the past, I only got my 1st computer in Oct. 2002, I have nobody to teach me and I'm sure I've learned everything backasswards. I just got it to learn exactly what I wanted to learn and that was audio and video. I've fumbled my way around until I ended up here. I do sincerely want to learn everything I can, but I'll have to do it at my pace. Right now, anything new, seems like a nightmare before you start learning how to use it. Especially just reading the computer terms used and reading how it works.
When you're using a Dig 8 and a Hi-8 for your main cameras, the 2ndary color corrector worked good enough for my needs. So right now, when you mention to look at the thing with the Vegas scopes, I don't have a clue what to even picture in my mind.
Most of my knowledge is from the analog world, the digital world is still a nightmare. So while it may seem as easy as tieing your shoes, to you, it sounds more like rocket science to me. At least right now it does. But I will get there eventually. So try not to pull your hair out waiting for me to do something that seems obvious to you. Someday I'll get those scopes out and I'll probably think it wasn't nearly as bad as I had expected. That happened with 'Frameserving' and I felt the same way about that when you 1st explained it to me. And now it seems incredibly simple.
I don't do this for a living and I have to make time for it.
The other problem is that I'm still living out of a single bedroom, while the rest of the house is in remodeling mode, and everything I do is crowded into a 10' x 15' room. (and the bathroom)
which makes wiring a big problem right now. The floor is a horrid mess of wires, discs, photo paper, AC adapters, magazines, Guitars, Basses, Digital Drums, trash, A/D converters, cameras in cases..... Well...it looks like a 14 year old lives here without supervision.
farss wrote on 3/15/2005, 4:37 AM
The scopes are incredibly easy to use, just turn them on.
Select Histogram. This will show you the value of each of the RGB channels and the energy distrubution in each one.
Typically each RGB channel should go from 0 to 255, the corresponds to 0 to 1 Volt in analogue land.
If all of you RGB channels go from say 10 to 255 then it's a fair bet something has shifted your black levels, probably the NTSC setup problem everyones been talking about. If they only start from say 30 but go all the way up to 255 then you'll have pretty washed out looking video because the blacks are actually grey. Same thing in reverse at the other end, if they're only going up to around 200 then the whites will be not as bright as they should. If it's all pushed up at the top end of the scale then it's very likely that the analogue video going into the converter was way too hot (just the same as happens when audio gets clipped).
This by the way is a very crude explaination of scopes and how to read them, I'm keeping it maybe even too simple but it's enough to look at something that has gone wrong in a conversion process.
The reason I keep pushing you to do this is without instruments words like "faded" or "loud" can mean anything to anyone, when you measure something then we can identify better what is going on, they give us objective clues. I do appreciate that things are a bit of a mess around you, that's when you really need to start using instruments and not your senses. It's no different to a carpenter cutting wood that's a bit longer than the last one, who knows how long that is?
You see for all we know, all your other video could have been too bright, and the ones you think are wrong are right! That's the advantage of measuring things with instruments.
Bob.
johnmeyer wrote on 3/15/2005, 7:14 AM
Although I haven't yet tried transfering to tape and then to the PC.

No, that is not what I suggested that you do. My suggestion was to record analog to the camera tape, and then play it back out through the analog connection to a TV set. Compare this, A/B style, with the original. Does the tape look "washed out" compared to the original?

Next, take that same digital tape and capture it to your computer. Then, play that back out through the camera to the same TV set. Does it look washed out? This way, you test the codec in the computer.
B.Verlik wrote on 3/15/2005, 12:33 PM
farss and johnmeyer,
Thanks again for trying. I will actually attempt both of these things in the next day or two and get back to this column with my experience. I'll drag out the scopes and wet my feet and I'll do the A/B test (I understand what you want). I'll have answers to both of these then. (or some weird explanation) Maybe even within the next 15 hours
Thanks again.
B.Verlik wrote on 3/16/2005, 2:22 PM
1st in answer to farss.
I finally got out the scopes and tried using them. This is what you said before:

Typically each RGB channel should go from 0 to 255, the corresponds to 0 to 1 Volt in analogue land.
If all of your RGB channels go from say 10 to 255 then it's a fair bet something has shifted your black levels, probably the NTSC setup problem everyones been talking about. If they only start from say 30 but go all the way up to 255 then you'll have pretty washed out looking video because the blacks are actually grey. Same thing in reverse at the other end, if they're only going up to around 200 then the whites will be not as bright as they should. If it's all pushed up at the top end of the scale then it's very likely that the analogue video going into the converter was way too hot (just the same as happens when audio gets clipped)

This is the line I focused on:

If all of you RGB channels go from say 10 to 255 then it's a fair bet something has shifted your black levels, probably the NTSC setup problem everyones been talking about.

Well, most of my levels were starting at the 1st line, about 16 with the lowest mark being one frame that hit 11 for an instant, but a few that dipped to 13. This was a little footage that was shot in daylight, driving in my car near the beach at about 2 hours before sunset. So while it was light outside, the camera was not on a mount and also was catching the inside of the car at times and this included the darkness in the vents of the air circulation system and shadows. The footage looks fairly normal on the computer monitor and yet I can also imagine it looking a little light. (It's close) On the other hand, it looks like it goes off the chart on the high end. No problem hitting 255. I didn't understand the settings for the scopes. Not sure how to set the 7.5 thing and the 16 to 255 thing. I just left them as they were and couldn't see any change when I changed them.
The one thing I can add, is that my "datavideo DAC-100" A/D converter box is set to 7.5 IRE and they (the manual) do say that Japan uses 0 IRE. Of course my TRV-730 manual says nothing about the camera's IRE. I just went thru the manual for the camera again and could find no mention about this, which means to me, that it should be set to work.
So far, this doesn't sound real good, but I know I can fix the image afterwards. That is, once I figure out how to use the scopes and color correcters right.
Edit: Update....That histogram was just the luminance, when I added the Red, Green and Blue plus the luminence, all 3 (RGB) did go all the way down to 0 at times. Thought I'd add that, for what its worth.
Also, found some more .avi's transfered from VHS that same time as the original footage that caused me problems and put them in timeline. They look pretty normal on the computer screen. Even when I added the 'text logo covers' I didn't get the exaggerated effect I did that 1st time. (which nobody said anything about when I mentioned this earlier.)
I'm beginning to think that I must have done something in my editing the 1st time, because I did both the VHS transfer and the Satellite transfer one right after the other, but they were both edited on the same timeline, one behind the other.)
Okay, I still have to do johnmeyers test. :Edit.
Edit again: Made new transfers and they look great. This is embarrassing because apparently I made some kind of error when I put the original stuff in the timeline and never realized it. I don't know what I did though, as I couldn't repeat it. But the new transfers look as good as I could expect. Even when I add text coverups.
Thanks everyone, for your help. Bob (farss), at least I finally got out those scopes, even though I don't know what to do with them yet, I'll be delving into that now.
I actually had the composite feed of the S-VHS player going to the TV while the S-Video was going to the "Pass-thru" and was able to see the computer screen and TV at the same time and they nearly looked identical, even though the computer screen is LCD and the TV is CRT.
Again, thanks all for your contributions. I feel a little stupid right now. :Edit again