My first adventure into analog capture started with the purchase of brand new system and a ATI All In Wonder 9800 Radeon Pro video card capable of converting analog signals to a digital format. A month after setting up my new computer I finally had time to sit down and start learning the basics. After following the directions found in both the ATI manual and on DigitalFaq.Com I quickly noticed that all my captures had a intermittent noisy white band across the top 10 to 20% of the video, additionally I was getting a strobing / flashing affect in the entire frame. I want to stress the point that this noise and strobing were not present if the tapes were played normally from a VCR to TV. Assuming I had a problem somewhere I tried different combinations of connections and cables (composite, s-video or coaxial), hardware drivers, capture software, different VCR's and even the camcorder that was used to record the tape. At one point I even disconnected my speakers and moved them across the room. After countless hours of futile effort I could not under any circumstances get a good clean capture, If you are reading this you most likely know exactly the frustration I was going through. This lead me to search the Internet where I got the information I needed at VideoHelp. It was suggested by a member there that what I was seeing was the affects of a tape protected by Macrovision, or in my case what my capture card thought was Macrovision. After brief explanation from the poster as to why this might be the issue I tried a freshly recorded tape and to my surprise it worked perfectly leading me to believe this was in fact the issue.
What is Macrovision Protection
Macrovision was first used on VHS tapes in 1984 to copy protect video on VHS tapes, it is simply a video error inserted into the video stream of most commercial VHS tapes. This does not affect how it looks when viewing it on a TV, TV's are very forgiving of this error. Note that there are some exceptions, this did affect some older TV's when first introduced. What it will affect is attempts to copy a commercial VHS tape from one VCR to another. This manifests as video that jumps frames, video flashing from bright to dark such as the strobing affect I described above. Some of these symptoms very closely resemble a tracking problem. They can however vary widely especially with capture devices, some may simply put up screen stating the video is copyright protected.
How and Why is This on My Home Movies
The fact is it's not on your tapes, you would have to pay a fee to license this to place it on tapes. Macrovision should in no way affect the capture of your home videos. The kick in the teeth is your capture device thinks that they are copy protected. VHS tapes deteriorate over time. They develop video errors, these errors can be interpreted or detected by capture cards as copy protection producing an unusable useless capture. The ATI card is not the only device this false detection will affect, it can happen on practically any device capable of analog capture including camcorder's with passthough and DVD recorders.
A Few Examples From the ATI AIW 9800 Pro
The following is a sequential frame comparison of two clips from two movies. The screen shots on the left are from a first generation VHS home movie in excellent condition that has been rarely viewed, the ones on the right are from a commercially available VHS tape that has Macrovision protection. Both clips were captured with a ATI All In Wonder 9800 Radeon Pro. Both videos play as they should on a normal VCR to TV connection. Take note that whereas the corruption on the home movie captures appear sporadically the corruption of the commercial tape capture is throughout the entire length of the movie.
Frame 1 – How the Video Appears Normally
With the exception of the band on the bottom of the left example from the home movie and the band at the top of the one to the right from the commercial video this is how they should normally appear, these bands are in the overscan area which would not be visible on a TV and is quite normal.
Frame 2 – How it Starts
The top of the video begins to tear to the right and becomes corrupted. Notice the similarity. The only difference is the tearing of the Macrovision protected clip is much more prevalent, this is a frame by frame analysis so I'll stick with it. Scroll down for a nearly identical example.
Frame 3 – The Entire Frame Brightens on Both Clips
Frame 4 The Frames Continue to Brighten
Frame 5 The Frames Brighten Even Further
Frame 6 – They Return to Normal
One thing you have to bear in mind is that this is just 5 frames or 1/6th of a second. With that in mind you could imagine how terrible this must look from video running at 30 frames per second.
A Better Identical Example
A much better example of the corruption that appears at the top of the frame.
Video Comparison of Macrovision Compared to Normal Capture
The following .mpg example clips are from the same portion of the home movie. Both were captured using the same hardware with the exception of the capture card. From my understanding the Leadtek has no form of MV detection, it produces a flawless capture. Each clip is approximately 1.5 megabytes.
Is it just the ATI Captures
No it is not just the ATI card, this can happen with many different capture devices. I experienced similar problems with the same tape on a Leadtek A380 (Nvidia GeforceFX 5950 VIVO). This simply produced a intermittent solid white bar across about 75% of the video. Some devices are more prone than others to this problem. As an example the same tape rejected by both the ATI AIW and the Leadtek A380 captured flawlessly on a Canopus ADVC 110 which also has Macrovision detection.
Work Arounds and Solutions
If this is affecting your captures your options are somewhat limited, ironically most options are used for circumventing the real thing. I am under no circumstances advocating piracy but having gone through the frustration of this experience myself will offer the following advice and possible solutions that I have come across. I make no guarantee that any of these solutions will work for you.
- TBC (Time Based Corrector) – A full frame TBC is by far the best method to fix this issue, but is more akin to the sledge hammer approach. A TBC is used for correcting timing issues common to analog tape like VHS. If you have ever viewed some very old and well used VHS tape you may have noticed what appears to be skewing. A TBC can fix this in many cases, it strips the timing from the video then retimes it. Macrovision resides in this area where the timing is so it's completely removed during this process. However these devices are not cheap. Starting at around $300 for prosumer models they are probably not in the budget of your average home user especially if you only have a few tapes to capture. If it is in your budget it's definitely worth considering some of the other benefits it provides. These can be purchased at your better video stores online or brick and mortar.
- Video Stabilizers – These are the "poor mans" version of the TBC priced from $30 to $100, they do not offer any timing correction. I did purchase a Sima Go-DVD which I tested on the Leadtek A380, it worked in my situation for this card. I did not have a chance to test it on the ATI because I had returned because of the very issue this article is about. Video Stabilizers can be purchased at your local electronics store or online at various outlets.
- The 1.08 WDM Driver – This is a very old version of the WDM driver for Nvidia VIVO cards and can be downloaded from various sources on the internet. Apparently this was the last WDM driver released by Nvidia that had no Macrovision protection. I installed this on a machine that had the Leadtek A380 installed and it worked, however from my assessment the capture quality was quite poor.
- Macrovision Detection Free Devices – I have no experience with any of these devices but I have read that the Hauppage MPEG hardware encoders do not look for the Macrovision signal, therefore they have no problems with this issue. There are other cards with various hacks available as well, research before buying if you are lucky enough to read this beforehand.