Can't work out resolution

[DLister]

Hi everyone! I'm new to this forum (and this whole video-editing thing), and I was wondering if you could help me answer a couple of questions I have been unable to work out myself. If you can answer even part of my questions, please do. I'm stuck... I am using a Canopus ADVC-100 to capture from an NTSC (NA) SVHS VCR, Windows Moviemaker to save the capture, and TMPGEnc to encode to MPEG2.

1) Whenever I load a video into TMPGEnc, it automatically sets "Source aspect ratio" (Advanced tab) to "4:3 NTSC 525 (704x480)." Windows claims that the video captured by the Canopus is 720x480. Does anyone know which it really is and why TMPGEnc always changes to 704x480 when I load the Canopus video?

2)When I began comparing frames from the original ADVC AVI frozen in Windows media player to frames from the encoded mpegs in Powerdvd, I noticed that the frames in the mpegs had always been narrowed. Going by eyeball, I suspect the avi is the correct dimensions and the mpegs have been horizontally compressed. Why is this happening? If I set aspect ratio (Video tab) to 4:3, and Source aspect ratio (Advanced tab) to 4:3, shouldn't the output be the same as the input? Why doesn't it look it on the monitor? Is this some property of the media player which will be corrected on TV, or is TMPGEnc really altering the aspect? The only way I can get the mpeg to appear the same dimensions as the original avi is to set source video to "1:1 (VGA)". Why does this seem to work, and which setting will actually be proper 4:3 when played back on the TV?

3)Lastly, I've heard some disparaging comments on the quality of TMPGEnc's audio encoder. I'm recording in Mpeg 1 layer 2 384 kbps. If I'm encoding stereo VHS tapes, am I taking a noticeable hit in terms of sound, compared to other formats, such as AC3, or encoders, or is it just fine for my purposes?

The stuff I've done so far looks good, but I want the digital versions to be as "perfect" reproductions as possible. Thanks very much!

Jerry

[Solarjetman]

2) This is not actually a problem. In actuality both the TV and computer are playing it correctly. The difference is the computer shows pixels as perfect squares while a TV does not. For example, both a TV and computer are 4:3 aspect ratios. Since a computer shows pixels as perfect squares, this also means the resolution will be in a 4:3 ratio (640x480, 800x600, 1024x768). But since the TV does not show them square, the resolution may NOT be a 4:3 ratio. The overall effect will be that the picture will become distorted while played on a computer display.

When you choose VGA for the capture, the resulting file is then made of square pixels instead. This will make it look good on a computer display, but if you were to play the resulting VGA file on a TV the picture would be distorted on your television.

Just remember that standard analog TVs do not actually show pixels. The DVD player converts them to an analog signal, so its you've got a few more variables as well. But this is a good way to visualize what is happening.

As for why it looks normal in your software DVD player, the software compensates for the different pixel shapes.

[johns0]

I thought analog tv`s showed honey combed shaped pixels.

[DLister]

Thanks Solarjet! That's good stuff to know.