Better Capture?

[booboobubber]

I'm capturing my home vids with Tv card & vitualdub/huffy codec Pal 352x288 25fp & then converting to mpg using TMPG Pal VCD. The end quality is not the best. Would I get a better result if I captured at a higher res or used no compression or is the problem with the covertion? When I look at the captured avi on PC it looks OK but I am experiencing high dropped frames in some sections of the capture. I also seem to have a bit of noise in them.
I have a P4,1.6GHZ,7200,40GB HD, 512RAM,TV capture card, Nvida tnt 2 graphics card. This should be fast enough for capture? I don't know why I'm having dropped frame problem.
Can anyone help?

[AlanCake]

Hi

I pretty much go through the same procedure as you do. I get fairly good quality in the resulting mpeg. One thing I would certainly recommend is not sticking rigidly with the VCD PAL template. Its worth while 'uping' the bitrate, say, to between 1700 and 2000 this improves the quality a good bit. Watch out though some players cannot play this type of mpeg.

Secondly, I make sure all the applications are closed down before I do any capturing. All those sneeky little anti-virus and system utilities should be shut down! I use an Athlon 700Mhz machine with 192Mb of RAM. I don't get any dropped frames with this setup although if I were to even move the mouse when I'm doing the capture I would drop some frames. The moral of this story is make sure that everything is shutdown so that all the system resources are focused on doing the capture. And, leave the PC alone when the capture is taking place.

Hope this helps

Alan

[Craig Tucker]

Also if you are capturing an interlaced source (which you probrably are capturing from vhs or TV), try doubling your vertical resolution to 576. Although a tv display or PAL VHS is 25 fps it is interlaced which means that the even and odd lines of video are displayed 180 degrees out of phase effectively giving you a framerate of 50 fps. If you capture at a vertical resolution of 288 you only capture either the odd or even frames thus losing 50% of the information.

If you play back this capture on your PC the image will look tall and thin and have interlacing artefacts (a combing effect during movement and around the edges of objects) this is because a PC screen has a progressive display and cannot display an interlaced video properly. If you are making SVCD you can encode this video using TMPGenc because SVCD supports interlaced video. If you want to watch the video on your PC or are going to make VCD you need to deinterlace the video.

Use virtualdubs deinterlace - area based filter available from their web site you do not want to interpolate instead of blending so deselect that box and set the threshold to 75 and edge to 0. This gives a fairly sharp image with very little blurring. You can then create your standard VCD with TMPGenc. If you want to watch your video on a PC you need to resize it with virtualdub to get the aspect ratio right.

Craig

[khelms]

Maybe I missed it, but the how to guides on this site don't seem to address interlace much. I have a few questions about this subject:

1. Are VCDs non-interlaced and SVCDs and DVDs both interlaced?

2. Can you encode SVCDs and DVDs as either interlaced or non-interlaced?

3. Does it always make sense to capture at double the vertical resolution when dealing with an interlaced input source like a VCR?

4. Do the "rules" change based on whether you're in an NTSC environment vs. PAL?

5. Should you capture and encode differently based on whether you plan to view the output on a PC instead of a TV?


Thanks to anyone who can shed some light on this!

[spidey]

Maybe I missed it, but the how to guides on this site don't seem to address interlace much. I have a few questions about this subject:

1. Are VCDs non-interlaced and SVCDs and DVDs both interlaced?

Analog videos and TV is interlaced - in this case your source is......

2. Can you encode SVCDs and DVDs as either interlaced or non-interlaced?

It'll clean them up if you deinterlace them, but you could encode it interlaced.............

3. Does it always make sense to capture at double the vertical resolution when dealing with an interlaced input source like a VCR?

If possible, yes, although I cap at 352 x 240 (ntsc) and don't have loss...but I am capping at 32 bit RGB in Huffyuv / Vdub

4. Do the "rules" change based on whether you're in an NTSC environment vs. PAL?

Yes, in terms of dimension and spec's.......not in terms or theory as to filters, etc.

5. Should you capture and encode differently based on whether you plan to view the output on a PC instead of a TV?

No, not really,...the PC will always pretty much look better than the tv, but the goal is to make the tv look great

Thanks to anyone who can shed some light on this!

No problem-o

[khelms]

Thanks for your response spidey. It did help me understand the issues although I do need a little more clarification.

I understand that TVs and VCRs are analog and, by nature, interlaced. Is the MPEG1/2 data on VCDs, SVCDs, and DVDs always the same format or can the data be formatted differently for interlaced vs. progressive output?

When I encode an SVCD with TMPGenc, there is a pull down that lets me select an Encode Mode of Interlaced or not. Does that create different output somehow? I used to think that digital data is digital data and interlaced or progressive output was a function of the player, but that TMPGenc option is confusing me.

[booboobubber]

Thanks everybody for your help.

Should I de-interlace and resive the captured AVI before I convert (S)VCD? I want to edit the AVI in Power Director or Video Studio before I convert. Will editing in these programs lesson the quality of the captured AVI? What would be the best way to save the edited avi without losing it's captured quality?

[Bud]

I do my Captures witha Hollywood Bridge via the Firewire, using Premiere 6.0 set at 720x480, (DV AVI format) no compressons, no filters. I end up with about a 35GB file for a 2 Hour movie, I then use VirtualDub and open the AVI, set the resize filter to 352x240 (only filter, sometimes the deinterlace depending on the capture, check your AVI prior to using any filters), then do a frameserve to TMPGEnc, I set up the Sharpen filter here to 75, select the Standard VCD template and let it run, the end result is a GREAT VCD, I do captures from a Digital Cable system so the starting point is already in great shape. Now one point ....that's great for me, what I see and what you see WILL NOT BE THE SAME. So use what ever you like and suitesd your needs.

Bud

[Craig Tucker]

khelms

I understand that TVs and VCRs are analog and, by nature, interlaced. Is the MPEG1/2 data on VCDs, SVCDs, and DVDs always the same format or can the data be formatted differently for interlaced vs. progressive output?

VCD's do not support interlaced video, you could still encode one and play it on your TV but it wouldent look very good because of the interlacing artefacts I mentioned earlier.
SVCD's support interlaced video and can output it as such to a tv with an interlaced display, you could deinterlace the video and it would still play ok, but it makes sense if possible to output an interlaced video to an interlaced display

For a detailed explination of interlacing and a lot more info on video capture visit this very informative site.
http://www.geocities.com/lukesvideo/

booboobubber

Should I de-interlace and resive the captured AVI before I convert (S)VCD? I want to edit the AVI in Power Director or Video Studio before I convert. Will editing in these programs lesson the quality of the captured AVI? What would be the best way to save the edited avi without losing it's captured quality?

Yes you should deinterlace for VCD but not for SVCD you do not need to resize as if you use the tmpgenc templated it does that for you. I cant comment on your software as I have no experience of it, but if all you want to do is some trimming and filtering virtualdub is very good and there is no degredation in quality. Save as YUY2 with huffyuv compression.

Good Luck

Craig

[booboobubber]

Thanks
I still have a couple of questions.

1. When I capture with virtualdub should I use the HUFFY codec or should I use the HUFFY codec after I edit the avi and then save it?

2. If I resize the captured AVI before I edit (I want to add transitions music etc) will I lose quality when I save the AVI after editing? Also will the resized AVI still produce a better(S)VCD after converting with TMPGNE or is it better to leave the size as it was when it was captured and let TMPGNE resize in the conversion?

[Craig Tucker]

Use huffy for both capture and saving.
I would do the transitions etc before resizing and let tmpgenc take care of it. However, If you use a lossless compression codec like huffy there should be no degredation in quality when resizing with vdub. The VCD will be better captured at the higher resolution whether you resize it with vdub or let tmpgenc do it when you convert to mpg1. It has to be resized I dont think the quality will be any better or worse whichever method you use.
If you are making SVCD do not resize or deinterlace as SVCD can support interlaced Video, add your transitions and then encode the interlaced video to mpeg2

Craig

[booboobubber]

Thanks, I really appreciate the replies.

I have one more question. I've decided I'm going to produce an SVCD and I'm not sure now whether it is still right to double the vertical resolution as the Pal SVCD format is 480 x 576 so if I use the Virtualdub Pal SVCD template to capture I'm pretty sure it will capture at this size. Also should I leave the bitrate as per the template?

[droolian01]

Just a quick tip.
Huffuv (and mjpeg) captures using bt8-8 cards can sometimes end up with the fields being reversed. Just do a test cap of a channel with a logo at the top, zoom it to 200% and look. Now go into vdub and get the huffyv configuration screen up (from any "video compression" option) and select reverse field option (for broken capture drivers!). Now play your clip at 200% - any difference?

This probably won't apply to you, but this simple fieldswap (i do it while in the filters while making divx) is very easy and can make a huge diference. Your computer may be beefy enough to do it on the fly during capture, but mine isn't!

[booboobubber]

I've also heard if a TV card uses video bus mastering it can cause the frames to freeze with certain graphics cards. I have Nvida TNT 2 and the Nvida web site does touch on this problem but only outlines a fix for 98 & ME operating systems. I use window 2000 pro and the fix didn't work for me. I was wondering if anyone has experienced the same problem and whether you know how to fix it. I'm not sure if this is causing the dropped frame problem I metioned in my first post when capturing or not.