Originally posted by: Moth3r
When you capture a video signal, the waveform is digitised. Formulas (e.g. Nyquist) are supposed to give how many pixels you need to sample to ensure all the horizontal detail is captured, and I believe that's where this guy got the 528 and 544 from. (Depending on how you calculate the sample rate, I've seen this figure quoted as 600 for laserdisc, see section 3.5 of the Doom9 capture guide.)
But this is all academic when you're capturing to make a DVD. Since the final desired resolution is 720, you should alway capture at 720 to avoid having to resize later. (I know I cropped some blank pixels down to 704 for my DVD, but I didn't resize, I just added in an 8-pixel wide border either side.)
When you capture a video signal, the waveform is digitised. Formulas (e.g. Nyquist) are supposed to give how many pixels you need to sample to ensure all the horizontal detail is captured, and I believe that's where this guy got the 528 and 544 from. (Depending on how you calculate the sample rate, I've seen this figure quoted as 600 for laserdisc, see section 3.5 of the Doom9 capture guide.)
But this is all academic when you're capturing to make a DVD. Since the final desired resolution is 720, you should alway capture at 720 to avoid having to resize later. (I know I cropped some blank pixels down to 704 for my DVD, but I didn't resize, I just added in an 8-pixel wide border either side.)
We're on the same page when it comes to the more samples the better, in order to properly capture a waveform. The 720 horizontal you captured at is more than adequate given the source material. I think the only place where we have slighty differing opinions is where you state you should "avoid having to resize later". I think that you can eek out a little better picture quality (like lower noise levels without detail loss) by the downsampling and upsampling through some clever algorithm choices. But again that "quality increase" is very subjective and most likely not observable unless the picture is blown up a whole lot say with a projector... hence thats why I've been playing around with this.
