|
OK folks, here's a tough nut to crack. It's a long story that will get boring if you've never tried your hand at something like this, however I trust that there are others in Europe with NTSC video tapes that they'd like capture in crystal clear quality, so bear with me.
Where to start? Well, I have been using a Liteon LVW-5001 settop DVD recorder to make digital copies of old VHS tapes. It's a region 2 PAL recorder, and I use a standard issue PAL VHS. As you'd expected, everything works hunky dory when I am capturing PAL tapes. Nothing to it so far.
I also have a handful of NTSC tapes that I can watch with my PAL VCR and any of the various PAL TV's in my household. My understanding is that this is because the PAL VCR will output NTSC tapes as 'pseudo-PAL' or PAL-60, which is essentially a PAL signal shown at 60 Hz. In other words, the VCR does a simple signal (colour) conversion but leaves the frame rate intact. As most PAL TV's don't mind the 60 Hz rate, the image is nice and clear.
Still with me? Good. Things get more hairy when you try to record a PAL-60 signal. Ordinary PAL VCR's can't make anything out of it, the frame rate throws them off and you get nothing but garbage. However my Liteon can record it, albeit with some difficulties. While a standard PAL recording at full D1 resolution is 720x576, recording a PAL-60 input results in a 720x480 recording with a 96 pixels tall band of garbage at the bottom. Nothing strange there, you say, that's what you'd expect from a signal that was originally NTSC. OK, fine with me.
What I can't figure out is the frame rate. When the Liteon makes a PAL 720x576 recording out of the signal, it's surely at 25 fps, right? Now if I make a 25 fps recording out of a 30 fps (60 Hz interlaced) input signal, I am going to throw away one frame out of six which -- barring some kind of bizarre image processing magic -- is surely going to result in choppy video in fast action scenes in particular. Right?
OK, bear with me just one more second. So I take the recording and do a bit of post-processing on a PC, cropping off the garbage at the bottom, rescaling to full 576 pixels tall, and recording it one more time on another DVD-R with a PC burner. Nice and easy, nothing to it.
Remember the bit about choppy motion? OK, so I take my homebrew DVD and stick it in a settop DVD player (a Region 2 KiSS DP-450). Lo and behold, I get exactly what I expected. A good enough capture with crystal clear image, however fast motion gets noticeably choppy just as I figured. No surprise, then?
Well, yes. Just out of curiosity, I go to DVD player setup and select NTSC output instead. Yes, NTSC. So now I have a PAL DVD that I am playing in a Region 2 DVD player and watching the results on a PAL TV. PAL all the way, no question about that. Except that I go and tell the DVD player to display the disc in NTSC instead. Go figure.
Well, what do you know. The choppiness is gone. THe motion is smooth all the way. I feel dumbfounded, like someone slapped me in the face. WTF? What just happened?
Can someone, anyone, pretty please, enlighten me what on Earth is going on here? How can the DVD player config possibly make a visible difference and miraculously recover the smoothness of the original 60 Hz video? What, pray tell, have I overlooked here?
|
