Horizontal black bars in the middle of the picture

[apjorz]

Hi!

It may be not the most common problem, but anyhow, it's the best place to ask ;).

I'm having trouble with a capture card like this:

link (http://www.kobicctv.com.tw/KP-304,308,312,316.htm)

It's the KP-308. It has 4 analog channels and 4 bt878 chips to process the signal. I also have some surveillance cameras, Kobi and Sony models. I want to get picture and - after a lot of work:) - capture from four surces. The resolution does not have to be too high, I would be content with 352x240 @25fps per source. But for now, even using one source gives me a headache. :)

I managed to install the hardware and software, and I can view the images of the cameras with the included software (SkyView-MS-W). The fps is not too great, but that's not the point. However, I'm practically unable to record artifact-free video with any software. I experience the following:

The included software seems very unstable on a Windows XP box (a Compaq brand machine, 1.2g celeron with 256 mbytes of ram). It crashes after almost every attempt to change the settings or the screen layout. Therefore, while the picture seems correct, I cannot record, only view.

When I try to view or record the images with another application, no matter if it's based on WDM (like VirtualVCR; this works best when it comes to fps, I suppose because the driver is WDM too) or Video For Windows (like Virtual Dub), I get a strange black line of about 10-12 pixels wide, in the middle of the picture, horizontally (see the attached picture). The line is probably not a video signal noise, since it's pure black, and can be seen on the picture even with no cable attached to the specific conector (basically a blue screen with a black bar, really nice but annoying :) ). I changed the cameras, the cables, tried it on a Win2k system (on a mobile rack; the colors were then awful in the Skyview application, but otherwise no change), and even switched the two cards (I happen to have two identical capture cards!). Also played with video standards, colorspaces etc. Nothing helped, the black line stayed no matter what I did.

I can still capture from the above mentioned applications, but the black line stays and ruins the picture. With VirtualVCR, the black line put aside, it works well: native resolution cap @ 25 fps with no frame drop. So I don't really think the slow machine can possibily cause this.

Two interesting things to mention though:

1. There are some rare cases when the black line magically disappears and reappears. Not in a short period, usually after a restart, but I do not change anything!

(Like last week: tuesday there was no black line when I shut down the system. Thursday when I booted it up, the line was there. Nobody touched the computer (the rack was stored in a safe :) ), nor the cables and camera setup. I couldn't manage to get rid of it that day, not even by uninstalling the card and re-plugging it in a different slot.)

I'm at present time unable to discover the reasons that lead to this behaviour. Unfortunately, this happens very rarely, and most of the time I'm stuck with the line.

2. The line does not scale with the image. It's about the same width when I increase the resolution to the double.

After some research on Google (very few results) my guess would be that this could be either a driver-related or a signal synchronization problem. But I did not find alternate drivers (or would btwincap work with this 4-chip card...?), and I don't know what I could do about synchronization.

I'd like very much to get rid of this black bar. It is not present when I use the included application, but this application sucks and crashes frequently too, so I want to be able to record without problems with other software.

Please tell me if you have any ideas on this subject, and do not hesitate to ask for further information!

Thanks in advance!

[apjorz]

No suggestions? :confused:

I'm about to test it on a different, somewhat more powerful computer at home. But I'm pretty desperate.

By the way, I wrote a mail to the manufacturer, no response til now.

[apjorz]

Correction: even 10 fps / source would be enough. Provided the framerate is stable and there is no black line :).

[Arachnotron]

I vaguely remember iulabs once sold a modded BT878 reference driver that could handle multiple cards. No idea if it could do the same with multiple chips on one card.

What happens when you play with the vertical resolution? (i.e. non-standard sizes.)

Another thing: what does Dscaler do? Since it bypasses the driver it might be interesting to see if the black bar is gone.

[edit] It seems the free iulabs driver now supports multiple devices.
http://www.iulabs.com/drv/download.shtml

[apjorz]

These are good ideas!

As far as I can remember, the bar stayed the same witdth when playing with resolutions.

But there are updates! I found a strange way to remove the bar... It's pretty late now, but I will come back and write about it as soon as possible.

Thank you for your help!

[apjorz]

So if anyone is interested.

I found out that the Skyview driver is responsible for the black line.

- if I use the btwincap driver, there is never any black line. However, the supplied Skyview software refuses to work with it, so we don't have anything we could record with (from multiple sources). Any software you could recommend?

- if I use the Skyview driver, the black line is there, in any application other than Skyview. Skyview, however, changes some setting when started, and removes the line, then when I shut it down, the line reappears.

PROOF: The fun part is, the Skyview software is so badly written that it doesn't handle the case when the device is used by another program. For example, if I start it with VirtualVCR running, Skyview crashes right away. And when it crashes, it doesn't have the opportunity to shut down properly and f*ck up the picture! So when I crash Skyview (in any way), the picture stays good, even from other programs!

So, to be clear, the method to remove this line is like this.

1. Start VirtualVCR. The image has the black line.
2. Start Skyview. It first removes the line from the image (I see the change in VirtualVCR!) and then crashes because another program is using the capture device.
3. Voilá, the image is now fine from any program.

Too bad the line comes back after a reboot... so the problems are now:

- if I use the Skyview driver, I have to do this crap every time before I can start using the device from other apps.
- if I use the btwincap driver, the image is fine, but Skyview app refuses to work :)

Could anyone recommend a software that can record from multiple sources in huffyuv? (possibly with motion detection or sync start) The Skyview is not good enoug, because it's a bit unstable and can only record with is own lossy codec.

[Arachnotron]

The dscaler package comes with a utility called regspy that allows you to see the status of various registers of the BT878. Maybe you could use it to track which register is changed by the skyview proggy.

Maybe, just maybe it is one that is accessable another way.

[apjorz]

Thanks, it's a good idea! I also tried to make and compare snapshots of the registry (with and without the line) and trace what settings Skyview has changed, but no result until now. There were many keys changed and neither seemed to be 'the one'. :)