Update on ATI TV Wonder 650 USB Auto Gain Control (AGC) Issue

[Mini-Me]

I just spoke with technical support at AMD (ATI), and David there spoke with one of the engineers on my behalf. They initially said that there are no end-user driver adjustments we can do to adjust/disable the AGC. I pretty much already figured that though, so I pressed on and asked to know whether it is implemented in the driver, in firmware, or directly in the hardware.

According to them, the automatic gain control is actually implemented in software, and I took that to mean the driver. That's good news, because it means that it is at least technically possible to fix these devices, even if it would be extremely difficult to hack the driver appropriately.

Before getting off the phone, they also said that Cyberlink's capture software "might" have rudimentary controls with which to adjust the AGC. That's obviously a bit wishy-washy, and I don't think anyone would really want to capture with Cyberlink for real anyway, but it might be worth looking into, at least to see what kind of adjustments might have already been implemented by someone. Does anyone have/use this software?

Update: I just checked out the PowerDirector trial, and while I can't even get capture to work, it doesn't look like there are any AGC controls there anyway. When they said there might be rudimentary controls, they were probably talking about the proc amp. Barring open sourced drivers, it looks like our only hope for a fix is for someone with mad disassembly skills to do a driver hack. It's a shame, but at least there's hope. I recently obtained an old AIW as well, but the TV Wonder seems to have better sharpness, much better built-in chroma denoising, and better everything-but-AGC.

[jagabo]

When they said there might be rudimentary controls, they were probably talking about the proc amp.

That's my guess. And, as you know, the proc amp controls take effect after the AGC. So blown out highlights and lowlights can't be fixed. Thanks for the update though.

I suspect this is part of the ATI devices' Macrovision response. One of the ways Macrovision works is by screwing with the sync and colorburst signals in a way that causes VCRs to screw up when recording. I suspect the ATI devices are falsely responding to some small variations in the signal.

[usually_quiet]

Maybe by Cyberlink software, he meant Catalyst Media Center, which is reportedly Cyberlink Power Cinema 4, customized for use with some of the ATI TV cards. http://www.rage3d.com/board/showthread.php?t=33868867 I have Catalyst Media Center installed and running in a Windows 7 32-bit system using an XP compatibility mode, with the patch (for Vista?) applied..

I have done some test captures with it, encoding to MPEG2. Quite a few adjustments are available, if you know where to look and learn how to get them to stick with the awkward user interface. Some I have yet to figure out, like "Disable Pre-Processing". Proc amp settings don't seem to be among the available options, and they are not enabled in the drivers provided for Windows 7 32-bit.

Has anybody tried a video stabilizer or other device that removes Macrovision to see if it has any effect?

[Brad]

I suspect this is part of the ATI devices' Macrovision response. One of the ways Macrovision works is by screwing with the sync and colorburst signals in a way that causes VCRs to screw up when recording. I suspect the ATI devices are falsely responding to some small variations in the signal.

Macrovision on my ATI 600 causes no brightness or color variations, only digitally-induced picture corruption at seemingly random intervals. Does the 650 actually fluctuate from MV like the T200?

[jagabo]

I only have a few commercial VHS tapes. On the few that I've tried on the ATI 650 the picture turns into total noise after a few seconds. But Macrovision evolved through several forms over the years. So I don't know what happens with all forms of it.

[leonid_makarovsky]

So is there any way to turn AGC off?

[jagabo]

So is there any way to turn AGC off?

No. That's the problem.

[leonid_makarovsky]

That's bad. ATI USB 600 is an incredible capture device which doesn't blow up highlights and automatically adjusts brightness unlike ATI 650 series. If only 3d comb filter could be added to 600, then this would be perfect.