Poor capture from Svideo

RexA wrote on 6/22/2003, 6:01 AM
This may have been discussed before, but I didn't find a good match searching this forum.

I've just tried to capture some video from an SVHS tape and it is not working too well. I have a GeForce4 Ti4200 video card that will take analog input. I connected this via s-video to my svhs tape player. When I view the input image in the monitor window of the Vegas capture program it looks pretty good.

After I capture some video (NTSC source), playing the resulting avi shows some jerkyness and pretty nasty scan-line jaggies at the edges of moving objects. Looking at an portion where this is happening and stepping frames, I see a pattern to the frames -- 3 good frames then 2 with jaggies. This 5-frame pattern seems consistant.

For a comparison, I captured some video in a different application from the same source. This program only could capture mpeg2, and seemed a bit noisier over all, but it didn't show any of this motion and scan line stuff.

As I said the input looks good before capture but has these problems after. This seems to point to something in the digitizing in the capture program (to me anyway). Can anyone explain what is behind this problem or suggest a way to get beter results?

If anyone wants a look, I posted one of the worst frames here:


-Rex

Comments

farss wrote on 6/22/2003, 7:56 AM
I have much the same video card. Using it as a capture device is not recommended by SoFo. Having said that you might do much better using the capture software that came with the card. I believe that will only capture to MPEG1/2 but not to worry you can still bring that into VV assuming you have the MPEG2 codec from Main Concept.

I just had a look at the frame and it doesn't look too bad to me, the are a lot of interlace artifacts but that may well have been on the original, you get them all the time with video. They happen because each field is taken at a different time but on the preview screen you are seeing the two fields combined to form the one frame. On normal playback the eye averages them out.

I also think you have a pulldown problem, this is used in NTSC to convert from 24fps film to 30fps NTSC.

Before you decide its not working so well, try rendering a section of the video in Vegas and then play it back to see how it looks.

I use my D8 camera to do analogue capture and it works a treat. I probably should try the ViVo on my video card again, last time I tried it on another app it looked pretty poor but I have a need to output analogue NTSC to my NTSC SVHS VCR and my camera being PAL just will not hack it.
mikkie wrote on 6/22/2003, 10:00 AM
From everything I've read, video capture from a g-force is often dependant on the software the brand decides to furnish -> might want to seriously search out any g-force fan sites for tips etc. and possibly using another software set.

Some have the opinion that the g-force video capture is an add-on feature and not up to the results you'll get with a dedicated capture card or an ati aiw etc.

There are several programs out there designed for analog capture rather then DV like Vegas capt app. Search this forum and you'll find suggestions and comments.

Try captureing all I frame if you do mpg2 capture if possible.

You can buy a box to convert analog to DV, search here for recomendations, or use *some* DV cameras.