|
|
| Slabak |
| Posted: Sep 24 2002, 05:45 PM |
 |
|
Unregistered
|
On doom9.org forums (topic titled: PAL resolution IS...VHS resolution IS...) is talked about kell factor - number which defines the vertical resolution of video signal sources. I think that some senior members here in vDub board should also say something about that. And also about video bandwidth of NTSC, PAL (D/K, B/G), VHS, video 8 camcordes etc. I think we can finally get the maximum 'reasonable' resolution for our capturings.
please |
|
| fccHandler |
| Posted: Sep 24 2002, 07:10 PM |
|
|
Administrator n00b
Group: Moderators
Posts: 3961
Member No.: 280
Joined: 13-September 02
|
Kell what?  (I'm flashing on "Dark Forces" for some reason...)
I've read all those technical documents and only ended up being thoroughly confused. But I'll describe what has always worked best for me. (Just my opinion, others may disagree):
[begin: My Opinion]
If you are PAL, always capture at a vertical resolution of 576; if you are NTSC, always capture at a vertical resolution of 480. In each case this ensures that you are capturing both fields of the interlaced signal. (It's always best to have both fields intact, especially if you are going to do any fancy deinterlacing, IVTC, bob, weave, knit, sew, whatever.)
For the horizontal, choose a resolution that closely matches what your intended output width is going to be. For instance, if you intend your final video to have a resolution of 384 x 288, capture at a horizontal resolution of 384. If you intend your final video to be VCD 352 x 240, capture at 352. I think it's pointless to capture at a super-high horizontal resolution and then scale it down, although some crazy people actually recommend this.
After your fancy deinterlace, you may still need to scale down the vertical resolution for VCD or whatever. I normally use VirtualDub's "Precise bicubic (A=-1.00)", just because I think it makes thin lines look smoother (particularly for anime). I've found that the Precise bicubic filter works best in this respect if the scaling ratio is exactly 2:1 (i.e., scaling 352 x 480 down to 352 x 240).
[end: My Opinion]
--------------------
May the FOURCC be with you... |
|
| Slabak |
| Posted: Sep 24 2002, 10:09 PM |
|
|
Unregistered
|
Yes, I think everyone is confused from these technical things. One half of video maniacs recommends capturing at maximum possible res. of your card. Second half (not exactly half, i would rather say 0 - 5%) before capturing always wants to find all specifications of their current video source to decide what resolution to set in capture program.
It would nice if someone make a really big a comprehensive benchmark from which we could always set max reasonable resolution.
With reasonable i mean: A resolution with maximal amount of video information and with minimum size. Everything over it can you get with bicubic enlarging of frame of reasonable resolution (and maybe some sharpening). TV transmitters reduce the amount of information which has movie in TV studio. TV signal of for example full PAL movie flies to your antenna reduced because of video bandwith of broadcasting.
Capturing the same frame in reasonable resolution and resizing it to full PAL size (768x576or575) should give you the same image as captured frame at 768x576.
OK, thats my opinion (which is changing everyday). |
|
| fccHandler |
| Posted: Sep 24 2002, 10:37 PM |
|
|
Administrator n00b
Group: Moderators
Posts: 3961
Member No.: 280
Joined: 13-September 02
|
The confusion originates because people are trying to quantify the "resolution" of an analog waveform (the broadcast signal). Theoretically, that signal has infinite resolution (at least down to the atomic level), and I doubt there can be any agreement on what its "reasonable" resolution is.
That's why I say capture at a horizontal resolution close to what you want your final width to be. (If you are making a full PAL video, then by all means capture at 768 x 576.) Your capture hardware internally samples the incoming analog signal at whatever resolution you request, so there should never be a need for you to resize the width.
--------------------
May the FOURCC be with you... |
|
|
