Verticle Stripping pattern from SDI capture at DVinfo.net

Jason Rodriguez · March 28th, 2003, 03:33 PM

Hello,
I'm wondering if anyone here has experienced this problem with captured footage from the DVX100 through an SDI source. My current setup is from a DSR-80 into a Digital Voodoo 64RT on my Mac. The only problem is that these stripes also appear on the other DSR-1800 decks (I tried a couple different ones) at my workplace, so I know it's not the deck. I also thought that maybe it was an incompatability with Panasonic MiniDV tapes, so I also recorded on a Sony tape, and I got the same results. Additionally, it's not just my camera. Another department here owns a DVX100, and their footage has the same purpleish stripes through it, and its serial number is much earlier than mine, which I would assume means they were not from the same batch. My serial number starts with a KT2, so it's later than the JT2 series. Also these stripes are not on the tape itself, as I've firewired the footage in, and on that footage the stripes are not present. Instead that footage has some ugly 32x8 pixel "blocks" that move around from frame-to-frame in an annoying random fashion (or they sometimes clump together in larges masses, but you can still see that they're composed of 32x8 blocks piled together. They are only in the chroma channels, not the luma channel. The stripes on the otherhand are in all channels, both chroma and luma). I'm not sure if this is a problem with the AppleDV codec or not. Does anyone with Avid DVXpress 3.5 have this same problem with their footage? The stripes are most visible in the dark areas, but when you try to color-correct the footage, they really jump out. If this has something to do with using MiniDV tapes in a DVCam deck, then can you use DVCam tapes in the Panasonic? Is there any way to SDI in the DVX100 footage without getting these stripes? Is there a specific deck that must be used, or can it only be Panasonic decks? I've made a rudimentary webpage to show some screen grabs of both the verticle stripping and the 32x8 random "blocks". it's at:

http://www.geocities.com/turbochrg/images.html

If anyone has any solutions for both me and the rest of the DVX100 community, I would greatly appreciate it. Thanks.

James Early · March 29th, 2003, 12:35 PM

Jason,
I want to apologize in advance for how this reply is going to sound but I have read quite a few posts on various boards concerning this problem and I've noticed a very disturbing trend, namely no one knows how to turn on a friggin light!

In every case I've read concerning these problems the situation has been the same. "Hi, I shot these in little to no light, and they don't look right." or " Hi, I shot this scene where the contrast ratio is like 10:1, with Iris wide open and for some reason there seems to be an image problem, oh and just so everyone know what I'm talking about I took it into Photoshop and brought the levels up." This process has been repeated over and over and yes there is a problem here, it's called user error! I've been a camera man for ten years, both in film and video, and I can tell you that the best SD Camera could not perform under these conditions.

Here's a little lesson in camera technology kiddies so listen up. The CCDs in your camera convert light into an electronic signal that's processed, compressed (in the case of DV it's compressed 5:1), and put on tape. So the basic rule of thumb is the less light you have, the weaker the signal from your CCDs, the more of a chance the information is going to be processed wrong. Compound that with the fact that your using a color space sampled at 4:1:1 and your asking for problems.

When I bought my DVX I did my test shooting using indirect sunlight coming through a sliding glass door as my key light and a color corrected 200W fill light. I was amazed at the quality of the image. I would never have attempted such a feat using a Betacam SP. The fact that these newer generation camneras have better low light response dosen't mean you don't have to light, it just means your lighting can be more subtle. Another thing to remember is that spec. sheets are produced by a company trying to sell a product. Results may vary.

I'm not saying there aren't legitimate issues out there it's just the examples I've seen fall into this arena. And if you are having problems under "normal" conditions then send it in. I'm sure they'll fix any lefitimate problem that may be an issue.

That's all I have, sorry for being a cranky old camera guy.

Jason Rodriguez · March 29th, 2003, 05:56 PM

No, no, you're definetly right about the "no lights" thing really pushing the camera to the extremes. Actually, the reason that I'm concerned is that I bought the camera to shoot a documentary this summer in Costa Rica, and due to transportation and other circumstances, I'm not going to have a lighting kit-the only light that I'll have is the natural light or existing light that's available down there. So I get kind of worried when I try a "push the camera till it breaks test" and then I get this wierd verticle stripping pattern that is ONLY found in DVCam decks, whether I use the analog or SDI outputs. The bad problem is that if I want to finish on my Digital Voodoo setup at work, I'll have to go through an SDI connection from one of these decks, hence my concern over the "verticle stripping". So yes, these are very bad aesthetically done shots that I normally wouldn't consider, but I believe they will be the type of shots that I'll have to deal with down there in the Costa Rican jungle (based on other footage that a friend has taken to the same area on the same types of trips). Hope this helps.

Jason

March 28th, 2003, 03:33 PM	#1
Jason Rodriguez Trustee Join Date: Mar 2003 Location: Virginia Beach, VA Posts: 1,095	Verticle Stripping pattern from SDI capture Hello, I'm wondering if anyone here has experienced this problem with captured footage from the DVX100 through an SDI source. My current setup is from a DSR-80 into a Digital Voodoo 64RT on my Mac. The only problem is that these stripes also appear on the other DSR-1800 decks (I tried a couple different ones) at my workplace, so I know it's not the deck. I also thought that maybe it was an incompatability with Panasonic MiniDV tapes, so I also recorded on a Sony tape, and I got the same results. Additionally, it's not just my camera. Another department here owns a DVX100, and their footage has the same purpleish stripes through it, and its serial number is much earlier than mine, which I would assume means they were not from the same batch. My serial number starts with a KT2, so it's later than the JT2 series. Also these stripes are not on the tape itself, as I've firewired the footage in, and on that footage the stripes are not present. Instead that footage has some ugly 32x8 pixel "blocks" that move around from frame-to-frame in an annoying random fashion (or they sometimes clump together in larges masses, but you can still see that they're composed of 32x8 blocks piled together. They are only in the chroma channels, not the luma channel. The stripes on the otherhand are in all channels, both chroma and luma). I'm not sure if this is a problem with the AppleDV codec or not. Does anyone with Avid DVXpress 3.5 have this same problem with their footage? The stripes are most visible in the dark areas, but when you try to color-correct the footage, they really jump out. If this has something to do with using MiniDV tapes in a DVCam deck, then can you use DVCam tapes in the Panasonic? Is there any way to SDI in the DVX100 footage without getting these stripes? Is there a specific deck that must be used, or can it only be Panasonic decks? I've made a rudimentary webpage to show some screen grabs of both the verticle stripping and the 32x8 random "blocks". it's at: http://www.geocities.com/turbochrg/images.html If anyone has any solutions for both me and the rest of the DVX100 community, I would greatly appreciate it. Thanks.

March 29th, 2003, 12:35 PM	#2
James Early Tourist Join Date: Feb 2003 Location: Lemoore, CA Posts: 3	Jason, I want to apologize in advance for how this reply is going to sound but I have read quite a few posts on various boards concerning this problem and I've noticed a very disturbing trend, namely no one knows how to turn on a friggin light! In every case I've read concerning these problems the situation has been the same. "Hi, I shot these in little to no light, and they don't look right." or " Hi, I shot this scene where the contrast ratio is like 10:1, with Iris wide open and for some reason there seems to be an image problem, oh and just so everyone know what I'm talking about I took it into Photoshop and brought the levels up." This process has been repeated over and over and yes there is a problem here, it's called user error! I've been a camera man for ten years, both in film and video, and I can tell you that the best SD Camera could not perform under these conditions. Here's a little lesson in camera technology kiddies so listen up. The CCDs in your camera convert light into an electronic signal that's processed, compressed (in the case of DV it's compressed 5:1), and put on tape. So the basic rule of thumb is the less light you have, the weaker the signal from your CCDs, the more of a chance the information is going to be processed wrong. Compound that with the fact that your using a color space sampled at 4:1:1 and your asking for problems. When I bought my DVX I did my test shooting using indirect sunlight coming through a sliding glass door as my key light and a color corrected 200W fill light. I was amazed at the quality of the image. I would never have attempted such a feat using a Betacam SP. The fact that these newer generation camneras have better low light response dosen't mean you don't have to light, it just means your lighting can be more subtle. Another thing to remember is that spec. sheets are produced by a company trying to sell a product. Results may vary. I'm not saying there aren't legitimate issues out there it's just the examples I've seen fall into this arena. And if you are having problems under "normal" conditions then send it in. I'm sure they'll fix any lefitimate problem that may be an issue. That's all I have, sorry for being a cranky old camera guy. __________________ James Early ------------- For God so loved world, that he gave his only begotten Son, that whosoever believeth in Him should not perish but have everlasting life. - John 3:16

March 29th, 2003, 05:56 PM	#3
Jason Rodriguez Trustee Join Date: Mar 2003 Location: Virginia Beach, VA Posts: 1,095	No, no, you're definetly right about the "no lights" thing really pushing the camera to the extremes. Actually, the reason that I'm concerned is that I bought the camera to shoot a documentary this summer in Costa Rica, and due to transportation and other circumstances, I'm not going to have a lighting kit-the only light that I'll have is the natural light or existing light that's available down there. So I get kind of worried when I try a "push the camera till it breaks test" and then I get this wierd verticle stripping pattern that is ONLY found in DVCam decks, whether I use the analog or SDI outputs. The bad problem is that if I want to finish on my Digital Voodoo setup at work, I'll have to go through an SDI connection from one of these decks, hence my concern over the "verticle stripping". So yes, these are very bad aesthetically done shots that I normally wouldn't consider, but I believe they will be the type of shots that I'll have to deal with down there in the Costa Rican jungle (based on other footage that a friend has taken to the same area on the same types of trips). Hope this helps. Jason