What resolution do I capture at?

[bruce_lee]

I'm capturing a tv signal on my card (winfast xp2000) using virtualvcr, but what resolution do I use? I capture in huffy, and convert it to mpeg2 for dvd use. But if i do 640x480, and resize to 720x480 for dvd mpeg (using avisynth), it comes out stretched. But if I capture in 720x480, and convert that to mpeg2 dvd it still looks stretched. Infact the same as 640x480. So which resolution do i need to use? Thanks for any help. The source is tv, so its a full interlaced image, and i'm not ganna deinterlace it.

Edit: Meant to say it looks stretched when viewed on normal tv dvd player (of course also on pc).

[bruce_lee]

If I capture at 672x480, and not go through avisynth to resize, just open it up directly in CCE (Using 4:3 aspect ratio in options), the aspect ratio seems to be preety close to normal when viewed on tv. It does however add black bars on the side. Is this normal? How come capturing at 720x480 results in a stretched video when viwed on tv?

[Mac Sidewinder]

Take a look at the Capture guide at the top of this forum. It has a great section on frame capture sizes and aspect ratios.

Mac

[bruce_lee]

So going by what the faq says (if I understand this correctly), the resolution I need to capture at depends on the "active capture window" my card can capture/sample?

[jshumate]

I have a suggestion which you probably won't like, but I want you to seriously consider it because it will make your life a whole lot simpler. Your card supports direct MPEG-2 capture. Have you tried just capturing directly at 720x480 in MPEG-2 format? You should be able to just demux the recorded file and feed it into a DVD authoring program. How much time do you spend encoding your AVIs? You're not getting the results you want. Have you even tried recording directly in MPEG-2? You could do that at a very high bit rate, say 9600, and then re-encode it down to a lower bit rate if you want, or just record it at the bit rate you want to begin with. Or you can continue to beat your head against the wall and try to make your AVI recordings convert correctly. Personally, I have better things to do with my time than to record in AVI and spend hours re-encoding to MPEG-2 for no real improvement in quality. If you use a high quality hardware encoding card I don't think recording in AVI and converting is going to gain you anything in terms of quality over directly recording in MPEG-2. If you don't like my suggestion, that I suggest you consider that maybe the problem is with the way you are using AVISynth. 720x480 converted to 720x480 should NOT look stretched. Why don't you try my suggestion and just see if you get acceptible results. If you don't, then maybe you can get help in the forum that covers AVISynth.

[jggimi]

As far as I know, the Winfast TV2000 XP cards are based on the CX23881 chipset, which does not support hardware MPEG-2 encoding. MPEG-2 encoding, as with most PCI cards, is done by the CPU in software.

So the benefits of post processing from a lossless AVI capture, as per the Capture Guide, apply.

[bruce_lee]

Right I don't support hardware MPEG-2 encoding. Encoding to mpeg2 isn't too bad (using 3.6ghz pc). But the reason I don't do it straight to mpeg2 in the first place, is because I have to edit the video itself. And I have to re-encode it a few times between the different programs I use.

[Boulder]

Originally posted by bruce_lee
I'm capturing a tv signal on my card (winfast xp2000) using virtualvcr, but what resolution do I use? I capture in huffy, and convert it to mpeg2 for dvd use. But if i do 640x480, and resize to 720x480 for dvd mpeg (using avisynth), it comes out stretched. But if I capture in 720x480, and convert that to mpeg2 dvd it still looks stretched. Infact the same as 640x480. So which resolution do i need to use? Thanks for any help. The source is tv, so its a full interlaced image, and i'm not ganna deinterlace it.

Edit: Meant to say it looks stretched when viewed on normal tv dvd player (of course also on pc).

You're just not resizing correctly. Probably the easiest way to determine the correct resizing would be to use FitCD. It will give you the parameters you need and will show you the resulting aspect ratio error. I think it's generally agreed that anything less than +-2% is not noticable.

You just need to figure out if your card produces ITU-R BT.601-4 -compliant captures or not and tick/untick the correspondent box in FitCD..but it is probably explained in the Capture guide already mentioned. See what it says about that chipset jggimi mentioned.

Oh, and capture at the largest possible resolution (this depends on the ITU compliance as well).

[Wilbert]

So going by what the faq says (if I understand this correctly), the resolution I need to capture at depends on the "active capture window" my card can capture/sample?
Yup. Did you try to determince your active capture window?

What kind of chipset (cap card) and driver are you using?