Capture card native (hardware) resolution??

[alex1234]

I have an ATI TvWonder Pro capture card and wand to know what is the native (hardware) resolution of this card. I suspect, it's highest resolution is 320x240. I refer here to the hardware resolution i.e. number of horizontal x vertical elements that its analog-to-digital converter chip uses. All other resolutions that can be used with this card are software emulators which means that there is not point of creating a file with resolution higher than 320x240 because it is not going to contain more details anyway no matter what source is used.

The reason I suspect it is that if I capture to a native AVI (AVI has no software re-sizing emulation - whatever resolution IN, the same OUT) with resolution higher than 320x240 I see missed lines on the playback picture which looks like a zebra i.e. quality degrades.

The question - what resolution this card uses (internally, in its hardware chip)?

[dphirschler]

I have a TV Wonder Pro and it definately captures both fields (ie 480 lines). Even the TV Wonder VE captures both fields.


Darryl

[alex1234]

1. Was it an AVI you were capturing to?
2. I'm not sure what you mean by 'both fields' but the AVI that I have looks worst on all resolutions higher than 320x240. Besides, if I use VirtualDup to capture AVI, it does not even allow me to set a resolution higher than 320x240 saying "the resolution is not supported". The same behavior I had with my previous capture card, LedTek TV

[dphirschler]

In Virtual Dub, you have to turn off overlay. It's under the Video menu I believe. Then capturing both fields should work. You can turn on Preview to see what you are capturing.


Darryl

[alex1234]

"Both fields.." - could you please explain what this means and how it is related to the resolution of the AVI?

[dphirschler]

Check the glossary for a definition of "fields". But in short, "both fields" means all 480 lines of resolution.If you can get your capture card to capture both fields, then the width is only a matter of data transfer speed which could be limited by any number of things (hd drive, processor, bus, compression, etc). You goal is of course full DVD resolution 720x480.

Hope that helps.


Darryl

[lordsmurf]

I don't remember the native (600x485 or so), but with correct drivers and AVI software (VirtualDub), that BT8x8 card can do interlaced 720x480 alright.

See the DOOM9 forum and some of their documents for exact native size. FULCILIVES in this forum has covered it before too.

[alex1234]

If you can get your capture card to capture both fields...
You goal is of course full DVD resolution 720x480.
Darryl

Darryl, isn't software that comes with the card is supposed to be set to capture "both fields" by default (or "...full DVD resolution 720x480")? So, you are saying that I have to do something with software settings to make the card work correctly? Why don't the installation sets the corrects settings by default?

[dphirschler]

I forgot about drivers. My original vfw driver worked, but the newer ATI driver didn't. Check out the btwincap drivers.

http://btwincap.sourceforge.net/


Darryl

[alex1234]

I forgot about drivers. My original vfw driver worked, but the newer ATI driver didn't. Check out the btwincap drivers.

http://btwincap.sourceforge.net/


Darryl

Darryl,

thanks for pointing to the right direction! However, this is from the link you gave:

"...PS: Those drivers are for bt8xx(x) cards only. Don't test them on nvidia, Ati or other non bt8xx(x) cards, 'cause you probably harm your set up! ..."

I have ATI TV Wonder Pro, so it looks like these drivers are not going tp work Do you know where can I download 'correct' drivers (obviously not from ATI website)?

[lordsmurf]

ATI TV Wonder is BT8x8 ... that warning was for ATI THEATRE chips. You have cheapo BT8x8 chips. You're fine. Use it.

[alex1234]

lordsmurf,

this is an other post from the same place:

"... have an ATI TV Wonder card so I thought I would give this driver a go. After I installed the driver I launched Power VCR and the picture was terrible. Don't know what went wrong, but I had to revert back to my ATI WDM drivers..."

Do you still recommend me to try?

[dphirschler]

You won't hurt anything by trying. Note that your ATI software (TV, player, etc) will cease to work since they use driver-specific calls. However, there are freeware alternatives (such as Dscaler and VLC player). Also, if you are unable to make btwincap work then try an old ATI driver. I have one if you can't find it online. But I doubt you will have any problem. As Lordsmurf said, it's a bt8x8 capture card which is a well established standard.


Darryl

[alex1234]

Guys, thanks! I will try.

Darryl,

1. the alternatives Dscaler and VLC, can I capture with them to AVI?

2. "...if you are unable to make btwincap work then try an old ATI driver" - are you saying that there is an old ATI driver that would do the same improvements as btwincap but it will also work with ATI software recorder/TV?

[dphirschler]

Sorry, I wasn't clear. Dscaler is a TV viewer. VLC (also called VideoLan) is a file player.


Darryl

[alex1234]

Will VirtualDup work?

[alex1234]

...if you are unable to make btwincap work then try an old ATI driver. I have one if you can't find it online.

I tried to install btwincap and first the installation crashed my PC (Win2000) to a blue screen then after a restart "Found new hardware" crashed it again. I had to remove the installation.

I still have some questions:

1. why ATI did not make their driver to use full capability of its own card so users have to look for a 3-rd party solutions?

2. Is there an other driver I could try to make the best out of my card??

[BrainStorm69]

You might try the iulabs tweaked bt878 driver here:

http://www.iulabs.com/drv/index.shtml

Also, once you get a good driver to work, go here to determine the capture window:

http://www.arachnotron.nl/videocap/site/capture_area2.html

[alex1234]

I'll try, but still - why didn't ATI create a driver that would utilize the hardware the best way? What if this chip is not supposed to be used the way other than ATI uses it?

By the way, uiLab's VCR also hangs my system but I will try their drivers anyway...

[junkmalle]

why didn't ATI create a driver that would utilize the hardware the best way?

Probably because nobody at ATI knows how the BT chips work! They licenced the drivers from BT and included it with the hardware. They're not interested in updating software for old hardware, they just want to sell new hardware. They also don't want their low end products competing with their high end products. It's all marketing.

[alex1234]

I still can not get non-ATI drivers to work and still trying...

In the mean time, could someone please help me with this:

1. is it true that using ATI BT8x8 driver and capturing to AVI or MPEG with the resolution 320x240 or less captures both fiels and any higher resolution captures only one field?

2. is there any non-ATI BT8x8 card whose driver would not have the limitation described in 1) ?

Thanks!

[lordsmurf]

1. Not sure I follow. You get one field or blended for x240/288 capture. You get both fields at higher res, but can choose to interlace (or deinterlace... yuck!).

2. AVerMedia cards using BT8x8/CX8x8 are fine. But these 8x8 cards are bottom of the heap, lowest of low quality. You can buy better cards on eBay, slightly used, for as little as $40-50, things like ATI AIW and Hauppauge PVR.

[alex1234]

1. Not sure I follow. You get one field or blended for x240/288 capture. You get both fields at higher res, but can choose to interlace (or deinterlace... yuck!).

It's simple - when I encode with ATI to 320x280 I do not see 'steps' on vertical lines. When I encode to a highe resolution I see them. Doesn't this mean that 320x240 captures and encodes both fields?

2. AVerMedia cards using BT8x8/CX8x8 are fine. But these 8x8 cards are bottom of the heap, lowest of low quality. You can buy better cards on eBay, slightly used, for as little as $40-50, things like ATI AIW and Hauppauge PVR.

I tried to install AverMedia's drivers, the installation suceeded, I see the AverMedia's drivers in DeviceManager but... no video/audio even using VirtualDub or VirtualVCR

[junkmalle]

It's simple - when I encode with ATI to 320x280 I do not see 'steps' on vertical lines. When I encode to a highe resolution I see them. Doesn't this mean that 320x240 captures and encodes both fields?

No you have it backwards. You see interlace artifacts, "comb lines", when you capture at high resolution, because you get both fields (two pictures that were taken 1/50 (PAL) or 1/60 (NTSC) of a second apart). You don't see them when you capture at low res because you only have one field. But capturing at low res (one field) can will result in steps on nearly horizontal lines because of the missing scan lines.

Here's a full 720x480 capture, note the comb lines on anything that was moving (hands, heads):



Here's what would happen when capturing only one field at half res:



All the comb line artifacts are gone, but now you have jagged steps on nearly horizontal lines (like the white papers on the desk and the KUSI banner in the background).

[dphirschler]

It's simple - when I encode with ATI to 320x280 I do not see 'steps' on vertical lines. When I encode to a highe resolution I see them. Doesn't this mean that 320x240 captures and encodes both fields?

Capturing at 320x240 is throwing away one field. You are getting half the resolution.

What you encode at is a different subject. But in short, encoding at a different resolution than your capture is just gonna resize your captured image.


Darryl

[alex1234]

Yeee, it looks like I was totally misinterpreting the things...

Now, if I capture both fields at 720x480 isn't it what I need, both fields? The best? Why do I have comb lines then? Will I see them if I watch this MPEG on a TV? May be I should not worry about getting a 'improved' BT8x8 driver at all?

[dphirschler]

If you are capturing at 720x480, then you have successfully achieved your goal of quality captures. The captures combine apirs of fields into frames. When played back on a TV, the fields will be displayed alternately. You will need to make sure which field is to be displayed first and set that option when you encode your mpeg.


Darryl

[alex1234]

Darryl,

are you saying that if I see that my 720x480 MPEG2 created by ATI TV Wonder capture card looks like this on my PC:


I should not worry about anything, just burn it into DVD and on a TV it will be OK i.e. no combs and displaying both fields?

[junkmalle]

A PAL or NTSC signal doesn't consist of a series of FRAMES -- it consists series of FIELDS. Each field can be from a different picture (different points in time, different frames of film). When you watch TV you never see an entire frame, you see one field at a time. By the time a field is displayed the previous field has faded away. But on a progressive computer display pairs of fields are woven together to make a complete frame (hence the comb lines).

If you create a DVD from your hires capture, with the proper field order settings, you will see one field at a time on your TV, in the correct order, the same as the original video.

[alex1234]

If you create a DVD from your hires capture, with the proper field order settings

This is the DVD MPEG2, it is already created. Where do I set the proper field order?