More on saving VHS as DVD

wufred wrote on 10/28/2008, 4:04 AM

I read many of the threads in this forum regarding converting old VHS tapes to DVD, especially appreciate the time and again John's mention of option #1, recording directly through a camera to a DVD recorder. My question has to do with what is the best way to preserve the maximum amount of information, (quality). It seems that I can only record my video as VOB files using my Daewoo recorder. I am worried that there is so much compression that I will be loosing more of the already scant quality that I have left. If I want to save them as mpeg2, I would have to do Option #2, and indeed, I do have too many tapes. Am I worrying too much ? I just don't know enough about formats and compression that may be I am more dangerous to myself than not knowing anything at all. btw, John also mentioned somewhere that you break your files up to 20min segments, were those mpeg2 files ? I also have many many hours on D8 tapes, does it make sense to break them up and save them as avi files on multiple DVD's?

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johnmeyer wrote on 10/31/2008, 11:22 AM

My advice is to not worry about getting a time base corrector, unless you can see obvious problems in your video (see below). This device regenerates the timing signals that are present in an analog video signal. There is no need, nor indeed is there any meaning, for time base correction once the video has been digitized.

The main reason why TBC was so important when dealing with analog video is that the timing signals would shift or weaken (or both) as the video went through amplifiers, and moved down cables from one video box to the next. One of the biggest problems would happen when making copies (dubs) of existing videotapes because of the distortions inherent in the recording and playback process.

However, when you playback a videotape into a digital capture device, each frame is captured/digitized, and the timing information is thrown away. If you later play back that digital signal to an analog monitor, your playback device will recreate the necessary timing signals so the analog monitor can play back the video. Those timing signals are generated without any reference whatsoever to the original timing signals. So, in a manner of speaking, the process of digitizing does something similar to the TBC process.

There is one reason -- and this is the only one I know of, although others may know of other examples -- why you would still want a TBC when capturing analog video to digital format. If the timing signals get screwed up enough, you will get "flagging" (bending) of the video at the top of the screen. If your videos exhibit this, then you may be able to correct this by using a TBC.

You can also get errors between scan lines. Here is a link to a page that has some pretty darn good before/after photos, along with some excellent explanations:

Time Base Corrector Examples

Some Digital8 cameras apparently have a form of TBC built-in. Some of the more expensive analog to DV capture devices also include TBC. I don't know how these compare to the full-fledged (and very expensive) professional TBC units.

My guess is that your older tapes (those on 1" tape) may very well need this TBC help.