Quantcast Purple band on AIW TV and Captures - digitalFAQ Forum
  #1  
12-09-2004, 04:46 PM
Jerome Jerome is offline
Premium Member
 
Join Date: Dec 2004
Posts: 16
Thanked 0 Times in 0 Posts

Hello, I have an interesting capture problem which I haven't seen discussed anywhere. Very simply, I'm getting a purple-tinted band on every other frame recorded from upper-tier channels via a cable decoder box. As I'm sure everyone has experienced, I spent a lot of time debugging all the various problems that come up when attempting video captures, and thought I had finally gotten everything working perfectly. The digitalFAQ was very helpful, and that's why I'm here now.

Okay, now for the long explanation: when I started cropping pre- and post-movie junk from a recording (using MPEG-VCR), I happened to notice that some frames had a distinct purplish band all the way across, about 2/5 of the screen height, and a little above center. From top to bottom, it fades in and out smoothly. It does not move on the screen. It's most noticeable on flesh tones, but since it's on every-other frame, and I wasn't really scrutinizing colors, I didn't see it at first. Once I had an editor which would show each frame, I saw the obvious difference. Now it's driving me crazy.

Using the ATI AIW 9800's tuner, I get clean recordings, but of course it's limited to the unscrambled channels 2-79.
Using either the composite or S-video signal from the cable box/DVR (Scientific Atlanta Explorer 8000 on Time-Warner cable), the 2-79 channels are normal, but all the scrambled higher channels have this problem. It doesn't matter whether the signal is "live" from the DVR, or whether it's a program saved on its hard drive. I have tried short ATI PVR recordings at different resolutions, interlaced and not, but this doesn't matter either. It's just faithfully recording what is showing in the display, and is now apparent to me. Comparing multiple clips of identical footage reveals that a particular frame has an equal chance to be normal half the time, and have the purple tint the other times.

I have access to a AIW 9700, and swapping it into my computer gave the same results.

Even though I'm not very familiar with it, I've also tried capturing with VirtualDub 1.5.10. The screen display looks to have the same purple band, although maybe not as pronounced, but I don't have a tool which will show individual frames to see if the same thing is happening. This might warrant more investigation.

There are a few things I haven't tried. One is to call the cable company and ask them to replace the DVR. But, this problem does not exist on the television or VHS recordings (or on subsequent PVR recordings of those VHS recordings), so I haven't done this yet. I haven't tried a different version of MMC (finally got this version working), nor have I tried playing with BIOS settings.

Below are samples of two consecutive frames with the effect. It's not always so pronounced.

It seems like there's a slight interaction between the AIW and digital/scrambled channels of the DVR. The fact that it's not on every frame really has me wondering what is going on.

I hope I've explained clearly and someone has an idea what might be causing this. My system specs are below.

Thank you for your attention! Any questions and suggestions are welcome.
Jerome



SOFTWARE
Windows XP Pro, SP2 and all updates.
Basically the latest ATI software:
Catalyst Version 4.11
2D version&nbsp ;6.14.10.6490

Display Driver Version 8.017-041026a-018719C-ATI
Control Panel Version 6.14.10.5131
MultiMedia Center Versoin 9.02

MOTHERBOARD
ASUS A7N8X v2.0
AMD Athlon XP 2700+
2 of 512MB PC3200 400MHz DDR

CARDS
ATI AIW9800 video
Tekram DC-390U2W SCSI host
STAudio AudioDSP24 Value sound card
Creative ModemBlaster V.92 PCI DI5631 modem

DRIVES
Quantum Atlas 10K&nb sp;
Quantum Fireball TM2110
Seagate ST34555N
Seagate ST318404LW
Seagate ST336607LW (boot & software)
Seagate ST3120026A (video capture)
Seagate ST380021A

Plextor PX-W8220T
Plextor PX-32CS
Plextor PX-8XCS
SONY DRU-510A

Sony 3.5" Floppy
Iomega ZIP 100
Seagate STT3401A

PC Power & Cooling 510 ATX supply



Reply With Quote
Someday, 12:01 PM
admin's Avatar
Ads / Sponsors
 
Join Date: ∞
Posts: 42
Thanks: ∞
Thanked 42 Times in 42 Posts
  #2  
12-09-2004, 06:02 PM
admin's Avatar
admin admin is offline
Site Staff | Web Development
 
Join Date: Jul 2003
Posts: 4,337
Thanked 633 Times in 452 Posts
You've covered a good amount of ground, and your system seems fine. Most things that I would normally have considered as the problem do not seem possible because some channels works (lower band).

- Is this DIGITAL cable?
- If so, is it a fully digital stream, or a digitally-compressed analog stream? There are differences!
- What channels are you trying to get? (HBO, PPV, etc)
- Do these have any kind of broadcast flag
- Is the DVR equipped with some osrt of anti-copy mechanism?

It looks like a type of anti-copy. It does not seem to be one of the 3 Macrovisions, but may be one of the other ones. Now, WHERE it is coming from, that's the key. This may be simple color-striping anti-copy.

Have you attempted to use the Macrovision hacks on this site? They are found on the ATI guides. They probably will not work, but installing them should not harm anything. Worth a shot.

A timebase corrector (TBC) is usually called for in anti-copy situation, but for this case, I also wonder if some cheapo "enhancer" (like SIMA products) would clean the signal. It may be like killing an ant bed with an atomic bomb, but it's effective nonetheless. If that does not fix it, something else is wrong.

I can say that I 100% believe it is the signal or signal path. It does not sound like your computer, the ATI card, the software, or the AC power current. It's something else.

Maybe even try with different wires.

I wonder how a VCR would record this station, in the same spot as the ATI card. And then how the ATI card would capture this same recorded-on tape.

I would call the cable company and say that you are trying to record XYZ station with your computer PVR/recorder, and that stations 80+ have some sort of color banding/striping interference. Point-blank ask 'what causes this' and expect an answer. I can guess you'll have to bump it to a supervisor or higher level employee, phone clerks rarely have answers. .... AND I'm betting the answer is some sort of copy/recording prevention. It would be nice to verify, as we're sort of shooting in the dark right this moment.


- Did this site help you? Then upgrade to Premium Member and show your support!
- Also: Like Us on Facebook for special DVD/Blu-ray news and deals!
Reply With Quote
  #3  
12-10-2004, 05:09 AM
Jerome Jerome is offline
Premium Member
 
Join Date: Dec 2004
Posts: 16
Thanked 0 Times in 0 Posts
Hi! Thanks for your quick reply! I'll try to cover everything in order:

Of the first group - all good questions! I'm afraid I don't know most of the answers.
- I'm in the Jackson area of the Jackson Mississippi/Monroe Louisiana branch of Time Warner Cable. Their Channel Guide lists channel 1 and 100 upward in the Digital Directory section.
- I guess I'll have to call the local office to find out the details about their digital stream configuration. (I dread dealing with those people.) A possible clue: I've noticed a couple channels that, when first tuned to, have a blocky partial picture which is built up and filled in over a few seconds. Does that indicate anything?
- I'm almost exclusively trying to record the paid movie channels like HBO, CineMax, ShowTime, etc. and their variants. They are all in the channel 201 to roughly 250 range. I'm not interested in and haven't bothered with In-Demand PPV offerings.
- I'm not sure what you mean by a broadcast flag
- I'm not aware of any anti-copy mechanism on the DVR - if there is, then maybe it's a secret I've stumbled across.

It looks like a type of anti-copy. It does not seem to be one of the 3 Macrovisions, but may be one of the other ones. Now, WHERE it is coming from, that's the key. This may be simple color-striping anti-copy.

Yes, Macrovision crossed my mind, but I'm only familiar with the old VHS system. I didn't know they were up to 3 versions. I figured that something much more debilitating would be in play, if that was the case. But I agree that this seems most likely.

Have you attempted to use the Macrovision hacks on this site? They are found on the ATI guides. They probably will not work, but installing them should not harm anything. Worth a shot.

I haven't tried the Macrovision hacks yet, but maybe I will over the weekend.

A timebase corrector (TBC) is usually called for in anti-copy situation, but for this case, I also wonder if some cheapo "enhancer" (like SIMA products) would clean the signal. It may be like killing an ant bed with an atomic bomb, but it's effective nonetheless. If that does not fix it, something else is wrong.

I wondered about the TBC option, too. Not having any experience with this technique, and a very basic understanding of the TV signal, I didn't think a TBC would affect/fix the colorburst (?) portion of the signal. If it would work, I'm open to the idea. It might come in handy when I start delving into my mountain of old tapes.

I can say that I 100% believe it is the signal or signal path. It does not sound like your computer, the ATI card, the software, or the AC power current. It's something else.

That's good to know. Now I just have to fix the signal!

Maybe even try with different wires.

This, I have not tried.

I wonder how a VCR would record this station, in the same spot as the ATI card. And then how the ATI card would capture this same recorded-on tape.

Yes, I have tried this. I recorded a sample on a VCR (Sony SLV-798HF), and then turned around and captured that sample with the ATI. The signal was clean on the VCR, and the capture was good too.As I have it wired now, the composite signal passes through two VCRs before reaching the ATI purple input block. (The S-video path is direct from the Scientific Atlanta DVR.) I guess that means the VCR recording cleaned the signal.

I would call the cable company and say that you are trying to record XYZ station with your computer (because you hate VHS and have no VCR, and the DVR fills up awful fast... just say it to make the complaint sound good), and that stations 80+ have some sort of color banding/striping interference. Point-blank ask 'what causes this' and expect an answer. I can guess you'll have to bump it to a supervisor or higher level employee, phone clerks rarely have answers.

That sounds like a good approach, and it's mostly true! If I have time, I'll try calling this afternoon. I went through the same rigamarole once when I tried to get my VCR's "Cable-Rabbit" remote cable box controller to work on the previous analog cable box. It turned out to be impossible. Whatever remote control code number I chose in the VCR setup, it always added an "Enter" keystroke at the end, which would bump the box into one of the music channels. Not what I wanted to record! At least the guy I ended up with knew what I was talking about.

Reply With Quote
  #4  
12-10-2004, 09:39 AM
admin's Avatar
admin admin is offline
Site Staff | Web Development
 
Join Date: Jul 2003
Posts: 4,337
Thanked 633 Times in 452 Posts
Earlier this year, many cable and satellite providers began to yet-again carry copy protection on the "premium" stations, to prevent recording by digital devices. I'm not sure if this is the case, for your situation. So many things do not add up.

SIDE NOTE: A broadcast flag is just another form of copy protection, but made for all channels. If the notion of "broadcast flag" pisses you off, and it does many people, then join the Electronic Freedom Foundation (www.EFF.org), which sends your congressmen your opinion on these legislations that have controlled such things. At the moment, they want to force all transmissions to use these, starting with HDTV. These things should be struck down.

There are many copy protection methods. Macrovision is one of several companies that does it. And MV has three primary versions.

Anti-copy resides as an artificial error in part of the analog signal, but affects the image. A TBC will clean this off, as it replaces that portion of the signal with it's own clean "corrected" one.

Try different wires, different connections (s-video, composite, etc).

As far as the "type" of digital, I do not know. You can only find out by a pointed question, and by speaking to somebody at the company that is not clueless. Again "digital data" or "digitally-compressed analog" are the two choices. However, at this point in time, I am not sure this information would make any difference.

The DVR-to-VHS-to-ATI really throws me. Something about the DVR and the ATI, or somewhere in between seems to be the culprit. And again, try the hacks.



- Did this site help you? Then upgrade to Premium Member and show your support!
- Also: Like Us on Facebook for special DVD/Blu-ray news and deals!
Reply With Quote
  #5  
12-10-2004, 09:42 AM
admin's Avatar
admin admin is offline
Site Staff | Web Development
 
Join Date: Jul 2003
Posts: 4,337
Thanked 633 Times in 452 Posts
Here's more on the broadcast flags:
- http://www.eff.org/IP/Video/HDTV/
- http://www.eff.org/broadcastflag/

- Did this site help you? Then upgrade to Premium Member and show your support!
- Also: Like Us on Facebook for special DVD/Blu-ray news and deals!
Reply With Quote
  #6  
12-16-2004, 05:29 AM
Jerome Jerome is offline
Premium Member
 
Join Date: Dec 2004
Posts: 16
Thanked 0 Times in 0 Posts
Hello - okay, I finally have some more information, but it may not be very revealing.

I tried different wires, both composite and S-video, but this didn't help.

I retried the DVR -> VHS -> PVR test, to be sure, with the same result - the PVR recording is fine.

I tried the hacks, but they didn't help. Actually, I applied the "ATI MV Hack" first (didn't help), then tried to apply the "DisableATIMacroVisionDetection" hack, but got an error about it "already appears to have been patched". Then I tried the "ATI Macro" (this is for output only, right?), and still no good.

I also spent about a half-hour on the phone Saturday and again today trying to get answers to your first group of questions from the national and local Time Warner help desks. The lady I ended up with said that:
1&2) channels 100 and up are fully digital streams;
3) trying to get HBO, etc. (but you knew that);
4) "doesn't think" there's a broadcast flag
5) I forgot to ask if the DVR itself had an anti-copy mechanism - by now she had started hinting that I wasn't supposed to be recording like this and began comparing it to bootlegging. I got a little irritated and reminded her that time-shifting was still legal.

She went on about how "that's the way it is", and "there's nothing we can do about it". Very frustrating.

Number 5 may end up being the most relevant question. When I feel like spending another half-hour on the phone, I might try it again, if you think it's still important.

I happen to have an old Matrox Marvel card, which I could slap into my secondary computer. Do you think it would be at all worthwhile to try capturing with it? (I'm thinking probably not, but I'm grasping at straws.)

Lastly, do you have any confidence that a TBC would clean this up? As I said before, I'm semi-willing to get one, but I'd sure rather not waste the money. This wouldn't happen until a couple weeks after Christmas, anyway.

Thanks!
Jerome
Reply With Quote
  #7  
12-16-2004, 01:31 PM
admin's Avatar
admin admin is offline
Site Staff | Web Development
 
Join Date: Jul 2003
Posts: 4,337
Thanked 633 Times in 452 Posts
One of these may help remove the anti-copy, as I think there is some, but it's probably very weak:

http://www.bestbuy.com/site/olspage....4788270290&sku Id=6296572&type=product

http://www.bestbuy.com/site/olspage....4788291354&sku Id=6296563&type=product

Neither of these is a TBC, but they're based off of TBCs, sort of what I refer to as a cheap knock-off. Most people have a Best Buy local, so it's easy to buy (and return if it doesn't do the trick).


++++++++++++++++++++++


I would have had choice words for the woman on the phone, and began to quote her excerpts from the "Betamax" case (Universal City Studios, Inc. et al. v. Sony Corporation of America Inc, filed 30 January 1979, decided 17 January 1984). I would have CERTAINLY informed her that she was an uninformed lemming, and insulted by her insinuations. Something you may want to consider doing, should you talk to them again. I refuse to be dressed down like that by some ignorant phone jockey.

EFF has a very lengthy and thorough review:
http://www.eff.org/legal/cases/sony_...l_decision.htm l
.... a google search for "betamax case" will usually yield good results.


+++++++++++++++++++++++++++++++++++++++

You can certainly try another card. It will not hurt. ATI AIW cards have excellent quality that is not found with most other products, so I'd personally try to gravitate back in that direction if possible.

Had it not worked on the VHS tape, or the non-digital channels, I might have thought it defective. But that's not the case. Something about those channels, and ONLY those channels is the flaw.

Is there a way to bypass the DVR?
Let's try to eliminate (or isolate) that part of the equation.





- Did this site help you? Then upgrade to Premium Member and show your support!
- Also: Like Us on Facebook for special DVD/Blu-ray news and deals!
Reply With Quote
  #8  
12-21-2004, 01:46 PM
Jerome Jerome is offline
Premium Member
 
Join Date: Dec 2004
Posts: 16
Thanked 0 Times in 0 Posts
Hello, sorry about the long delay - like most, I've been really busy for the holidays. This'll probably be my last post until the new year.

I thought it was worth a try too, so I did in fact swing by the local Best Buy and got the Sima CT-2 model.

Briefly, it didn't help. I'm sure I got a defective one, though. It wouldn't power up out of the packaging. I finally resorted to a couple raps on the case, and then I got light from the LED. It functioned for about a half hour, and then it lost color from both composite and S-video inputs, regardless which regular/enhanced/dark/b&w mode it was in. The signal also had a strange herringbone effect. While it was working (although I'm not sure it was 100%) it didn't clean the purple band at all.

I wish it had lasted longer, because I would have liked to know how well it would stabilize a VHS tape I tried recording. I had a lot of tearing without it, but it still managed to straighten out the signal somewhat, although not completely and without color.

I'll return it, but now I don't know if I should try an exchange unit to see if it would work better, or give up on it altogether.

I haven't had time to try the Matrox card, but I agree that the ATI would certainly be my choice. In all other respects, I'm very happy with it - great captures, and right now everything is working beautifully and super stable.

Oh, and I don't think there's a way to bypass the DVR, since it's the only source of the signal I'd like to record.

I'll get back in a couple weeks, and try working on it then (if I haven't already used up my forum time )

Merry Christmas!
- Jerome
Reply With Quote
  #9  
12-21-2004, 09:29 PM
admin's Avatar
admin admin is offline
Site Staff | Web Development
 
Join Date: Jul 2003
Posts: 4,337
Thanked 633 Times in 452 Posts
The unit sounds like it's broken. I'd try one that works. Maybe try a CT-1 too.

- Did this site help you? Then upgrade to Premium Member and show your support!
- Also: Like Us on Facebook for special DVD/Blu-ray news and deals!
Reply With Quote
  #10  
01-14-2005, 03:51 PM
Jerome Jerome is offline
Premium Member
 
Join Date: Dec 2004
Posts: 16
Thanked 0 Times in 0 Posts
Hello again,

Well, last week I returned to the problem with a fresh look at things.

Iím afraid I made a fairly big mistake before, which lead us off-track. I thought that only the upper-tier digital channels had the color distortion problem. I see now that itís present in all channels and through every path (S-video, composite, cable) from the DVR to the ATI card. Basically, any signal from the DVR - connected directly, singly, and through different cables - to the ATI has this problem.

I exchanged the Sima CT-2 for a working unit, and although it did now help stabilize an old VHS recording, it did not fix the color distortion problem. I didnít see a CT-1 at the store and therefore havenít tried one.

Using my secondary computer, I tried both the Matrox Marvel I mentioned and the previously borrowed AIW9700 again. (A couple dayís work, getting them working!) The Marvel had no problem with the signal - nice and clean - while the AIW9700 behaved exactly the same as the AIW9800 does in my main computer.

Just for the heck of it, I even tried lifting the shield from the cable and composite inputs. No joy.

I think Iíve pretty much isolated the problem to what looks like a really odd interaction between the DVR and ATI hardware. So far, the only remedy has been the DVR -> VHS recording -> ATI route, which still produces a clean (but lower quality) picture. This gives some hope, but itís certainly not the way Iíd want to have to record things.

Iím afraid Iím back to one of my first ideas, to get the cable company to replace the DVR, in the off-chance that itís defective (and if I can convince them to do so); or to look further for a Sima CT-1 or some similar signal processor. Iím starting to get a little discouraged by the whole thing, but maybe this clarifies the situation for you? I sure hope thereís a light at the end of this tunnel.

Thanks for your help,
Jerome
Reply With Quote
  #11  
01-16-2005, 06:48 PM
admin's Avatar
admin admin is offline
Site Staff | Web Development
 
Join Date: Jul 2003
Posts: 4,337
Thanked 633 Times in 452 Posts
I think it's safe to say the PVR and ATI card hate each other. The signal from the PVR may be defective in some regard. Digital equipment is more sensitive than a VCR or tv set, which are rather "stupid" compared to the "smarter" digital devices. I see oddities all the time, though never one quite like this.

I may have somebody else look at this problem for you too, get a "second opinion" on it.

- Did this site help you? Then upgrade to Premium Member and show your support!
- Also: Like Us on Facebook for special DVD/Blu-ray news and deals!
Reply With Quote
  #12  
04-27-2005, 02:04 PM
Jerome Jerome is offline
Premium Member
 
Join Date: Dec 2004
Posts: 16
Thanked 0 Times in 0 Posts
I think you're right about the PVR and ATI hating each other.

In the meantime, I hesitate to mention that I wrote ATI about this problem, and lost a lot of time because it came to nothing (which is about all I expected).

But what I finally did do was decide to take a chance and get a real TBC, for two reasons: 1) it would very likely fix problems recording my older VHS tapes; and 2) who knows, it might even help with the color problem? I got a used TBC-3000 so that one channel could process the S-video going directly from the PVR to the ATI and the other could process the composite video going from a VCR to the ATI. I managed to get it for a little more than a new TBC-1000, so it seemed like a reasonable way to avoid changing cables often. Anyway, the conclusion to all this is that it actually helped with the color problem (besides working wonders on the tapes). It's not perfect, but it's close enough. If I look closely at alternate frames as I did before, there may sometimes be the same color distortion (especially noticeable in flesh tones), but it's much better. Now, during playback, even I don't see it.

In retrospect, I could probably have insisted that the cable company replace the PVR, but never got around to it. I needed a TBC anyway.

Thanks!

P.S. I have another question about video brightness/gamma and audio volume recording levels - would that be okay (probably in another topic)? - Jerome
Reply With Quote
  #13  
04-30-2005, 09:06 AM
admin's Avatar
admin admin is offline
Site Staff | Web Development
 
Join Date: Jul 2003
Posts: 4,337
Thanked 633 Times in 452 Posts
Sounds good, about the TBC. I suspected that would correct it.

As far as the other question, yes, just start a new topic on it.

- Did this site help you? Then upgrade to Premium Member and show your support!
- Also: Like Us on Facebook for special DVD/Blu-ray news and deals!
Reply With Quote
Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
Looking for WordPress music sidebar plugin for band site admin Website and Server Troubleshooting 0 10-07-2009 08:14 AM
Using VirtualDub for screen captures (for menus) lordsmurf Author, Make Menus, Slideshows, Burn 1 12-10-2007 03:39 PM
? about sound card and ATI purple box jrnyhead Capture, Record, Transfer 1 07-11-2004 07:58 AM
9600 AIW captures excellent, but authorware wants to reencode ? -d00d- Capture, Record, Transfer 4 06-12-2004 01:58 PM

Thread Tools



 
All times are GMT -5. The time now is 09:09 PM