Capture Trouble with Canopus ADVC100?

Mikeeer wrote on 10/7/2002, 10:39 PM
I think what I am seeing is a problem related to video capture using the Vegas Video capture utilities.

The problem only seems to occur when I capture through my Canopus ADVC100. The source material is generally a VHS tape or other analog source being converted to digital through the ADVC100. The issue is as follows. At the bottom of the captured video is a horizontal band running accross the entire screen of what appears to be misplaced video. When using the Vegas Video built in monitor set up as a 360x240x32 preview window on a 15inch computer monitor the band vertically is approximately 1/16th of an inch and it appears to be some shifted version of the video above. You can almost make out what part of the screen it comes from but it shifts frequently. There are also 2 approximately 1/16th vertical bands of black running down the left and right sides at the edge of the video. It's almost like the captured video is not quite big enough but the top of the video appears clean.

When I do a direct firewire transfer from my camcorder this does not happen. The issue does appear to be a permanent part of the video files because when I play back the avi files captured using the ADVC100 and Vegas Video using Windows Media player the same thing happens.

The anomoly is generally not an issue when viewing a VHS tape or DVD viewed on a TV because the anomoly is cut off as it is outside the safe zone. It is however a huge issue when rendering to Quicktime files and other formats to be viewed on a computer as well as when viewing a DVD on the computer. The 1/16th space can be as much as a 1/4' when viewed on a larger computer monitor at 720x480, even worse as a DVD at full screen.

Does anyone have any idea what this could be from? I will ask the Canopus folks the same question. By the way from a reliability stand point the ADVC100 is rock solid, never looses a frame on capture though on print to DV tape it will cut out from time to time but that likely is the firewire port and IRQ issues I have tracked down.

Is there a way to work around the issue by cutting it out when rendering to Quicktime, Mpeg2 or Mpeg 1 using the Main concept plug in? So far I have not found one.

I would be greateful for any help anyone can offer.

Thanks
Mike

Comments

SonyDennis wrote on 10/7/2002, 11:10 PM
(posting in parts because of a browser problem I'm having)



Congratulations on the Canopus ADVC100, it's a great box.

The artifact you are seeing is the video head switch from your VHS deck. Since each video field is played back by a separate head, there has to be a switch-over somewhere, and with the VHS format, is in the bottom most lines of active video (cheesy, but it's usually in the overscan area and most people never see it).

Your best bet is to use the Vegas Event Pan/Crop feature to zoom in slightly on the video to remove the artifact.

Or, you could use Track Motion feature to zoom the whole track out, also hiding the artifact.
SonyDennis wrote on 10/7/2002, 11:10 PM
Even though digital devices (DV, etc.) don't have head switch artifacts in the video, they have other edge artifacts that can be dealt with in the same way, such as black bands on the right and left side due to 601 rolloff requirements, or single rows of mis-colored pixels along the top or bottom due to CCD filtering algorithms. Just crop them out.

This is never a problem going to TV, which has overscan. It's often a problem going to streaming output, which uses the full frame. But, since professional video has been produced to not have important things near the edge of the screen (only inside the so-called "safe areas"), cropping/zooming is the correct solution.

///d@
Mikeeer wrote on 10/8/2002, 9:00 PM
That did the trick. I can't tell you how happy I am to get this working and that someone knew exactly what the problem was.

I'll also say Vegas Video rocks. I have yet to be let down by the product and this is just another example of that. I'm new to video editing and production and while I have the basics down (at least what I consider the basics to be)pretty well I'm always amazed at what Vegas Video has to offer once you dig a bit deeper.

I agree the AVDC100 is a very nice box and I like the fact that it is external to the computer. It lets me move the high quality converters from computer to computer so I can work at home or the studio and buy just one converter.

Thanks so much for the help.
Mike