Virtual Dub Resolution Block

[Teslacuted]

I'm quite new to capturing so forgive me if I make any stupid statments. I bought a Pinnacle PCTV Pro capture card and connected it to the S-Video out of my Sky Digi-box (The box provided by Sky to decode the digital signal from the satellite). I want to capture the picture in full PAL but when I select a resoulution above 320 X 240 virtual dub jams, I know the card can capture at 720 X 576 as DScaler and the bundled PCTV Vision software let you watch TV at that resoulution. I'm using the drivers from sourceforge as described in the capture FAQ and I've tried VirtualDub, VirtualDub Mod and Virtual Dub VCR (latest versions of all). I can capture to some extent at 720 X 576 with ATV2000 but it's dodgy. Vdub can capture (and prewiew) perfectly at anything below 320 X 240 but the prewiew simply stops at anything higher. Does anyone know what is wrong? Has anyone else had similar problems?

Thanks,

Teslacuted

[Teslacuted]

I believe I may have found the source of my problems, the wrapper from Microsoft that allows VFW applications to access WDM drivers. Does anyone know of a decent VFW driver for BT848 chips? Any help is appreciated.

[Owen]

I use FlyDS and WDM drivers.
No problems.
Why do you want to use Vdub for capture?
If you have a powerfull PC, WDM works better than VFW.

Regards,

Owen

[jggimi]

I've had success with Vdub (and it's variants) using BTWinCap drivers.

http://btwincap.sourceforge.net/

[Teslacuted]

I eventually got it working, all I had to do was disable the Overlay preview, I can now capture at full PAL with Vdub I also discovered that XP cannot use VFW drivers at all. Does the microsoft wrapper that lets Vdub access WDM drivers use much CPU power? I'd like to capture directly to Divx because of it's tiny size but my processor just can't keep up,(P4 2.66ghz). I'm trying to capture from VHS, should I stick to 720 X 576 or use 320 X 240?

[scharfis_brain]

please, do only use 7**x576 and nothing else for capturing VHS.

But why are so many poeple thinking: VHS=320x240 ???

[Teslacuted]

Thanks, I'm planning on converting Season 1 of Family Guy to DVD, TMPG says that I can fit around 253 minutes onto a DVD at full PAL MPEG-2, but the total running time is 312 minutes, If I use 352x288 I can double the time, would there be much quality loss in doing so? I believed that that was the resolution VHS tapes used anyway. A drawback though is that I have to use MP2 audio, if I use BeSweet to encode to AC3 what bitrate should I set it to to get sound quality equal to a 164/192 kpbs MP3? And can I then mux the 2 streams together and play the disc in my stand-alone player?

Thanks,

Teslacuted

[scharfis_brain]

THe real Resulution of VHS is 576 columns (vert. res) and about 240 lines per column (hor. res).
But lines are NOT equal to pixels, because VHS is an analogue medium.

And because of the digital sampling, every line has to be digitized with 2 pixels. So your minimum capture resolution for VHS will be 480x576.

Making 352x288, you'll loose MORE than the half of your information provided by the VHS-Tape!

But you can choose 352x576 for encoding to MPEG-2, this res is called Half-D1 and is part of the DVD-Standard.

Another Thing: The resolution is not proportional to the resuling Filesize! The only thing, that influences the Filesize is the Bitrate!
And the bitrate can easily be changed in TMPGenc.

[Teslacuted]

Would there be a noticable quality difference if I captured at 480x576 as opposed to 720x576? I have just 1 other problem, there is a bar of noise at the bottom of the video, I'm know this is from the VHS but is there a way to remove it other than cropping? Would a de-logo filter work?

[scharfis_brain]

capturing at higher resolutions and a later resize is always better than a capturing at lower resolution. Only capture at lower resolutions if you are low at diskspace.


what exacly do you mean with "noise at the bottom"?
Do you mean those 8 flimmering lines, which are typical for VHS (haedswitching), or do you mean real noise (grain) ?

Logo-removal-Filters are only suitable for static background, ut noise is dynamic...
So there are two ways
1) crop it away
2) live with the noise/flimmering

[Teslacuted]

Yeah, it's 8 flickering lines, I guess I'll just crop it out, thanks for your help. Would you know roughly how fast a processor you would need to encode to Divx (1 pass, quant 1) at 720x576? Would the new 3ghz ones be able to do it?

[scharfis_brain]

Please don't ask me about speed related things.
I gave up optimising for speed. I only optimise for Quality.

Speed depends very much on how you're filtering.
And I recommend, that you are filtering your Video before encoding.

- deinterlace, but ONLY if needed
- noisereduction (ie. with conolution3d)
- chromashift (VHS shifts the chroma down by 2 lines)
- resize for achiving correct AspectRatio and Size

Please don't encode 720x576 with divx!
720x576 has the false AspectRatio, resize to 768x576 or any other Square-Pixel-Resolution.

In past I had some worst-case-VHS's which were that noisy, so the encoding was terribly slow due the filtering process
It was about 1 or 2 fps "fast" and took about a day to encode on my AthlonXP 1600+

btw: IMO SVCD is the best medium to store VHS, because its resolution is 480x576, which is optimal for VHS. SVCD can store your (eventually) interlaced Video without deinterlacing, so that there won't be any Quality loss because of deinterlacing.

[Teslacuted]

I have been using:
null transform
2:1 reduction HiQ
resize to 352x288
Deinterlace MAP
Dynamic noise reduction (threshold 15)

Is there a better noise filter than dynamic NR? Would stand-alone players be able to read SVCD files from a DVD -/+ ? I just bought a DVD burner and I don't like constantly swapping discs.

[scharfis_brain]

Did you read my last post? you didn't answer and your filtering is false:
why are you deinterlacing AND halfing the resolution? This makes no sense!
why do you apply 2:1 reduction AND then a resize to 352x288? resize alone will be enough.

other denoisers can easyly be found with the Forum-Search.
One of them I called already: Convolution3d Please use the Forumsearch. All my tips are referred to using AVIsynth, because you'll get the best results with it.

But If you want to further use VDub, I recommend this Filtering strategy:
- nulltransform -> cropping
- denoising
- eventually deinterlace (but only, if there are visible combs! don't deinterlace for SVCD or DVD)

- for resizing :
don't change th vertical resolution! example:
720x568 (576 - 8 = 568 because of cropping)
add black borders on botton (expand letterbox frame) so that 720x576 are achived. this res is good for DVD
480x567 is for SVCD
and square-resolutions like 768x576, 640x480 or 512x384 are good for divx.

I hope you've understood what I wanted to say, and i hope that this post is not that chaotically and full with language-errors...

I am very tired.... googd night.