"Dancing stripes" in Aver EZCapture's capture

[mdw]

Hello,

When I do a 720x576 capture with AverMedia EZCapture PCI card (Conexant BT848 based), there are spurious one-pixel high stripes "dancing" over the picture, example frame is attached.
This problem occurs only when capturing, not on preview. I tried all three BT8x8 drivers (original Aver drivers, btwin drivers and iuLab's tweaked drivers), but there is no difference. Also tried different capture programs (Aver's simple utility, iuVCR, AMCap, VirtualVCR). The problem also diminishes with lower resolution and from about 352x288 disappears completely. There's no difference whether I use Composite video or S-Video inputs.
Is anyone familiar with this problem? Is there any solution to it?

MdW

[jggimi]

Hello, and welcome to the forum.

These look like tape artifacts.

Does deinterlacing eliminate them?

[mdw]

Hello, and welcome to the forum.

These look like tape artifacts.

Does deinterlacing eliminate them?

The attached example is taken from a live feed form a videocamera, so no, they are not tape artifact. Also, they are exactly pixel high and perfectly sharp, so they are of digital origin.

As for deinterlacing, they seem to be mostly in field 2, so using only field 1 seems to help significantly -- but that means losing some resolution, if I understand things correctly.

Regards,
MdW

[Jay Bee]

I have what looks to be pretty much the same artefacts on my AVerTV Hybrid+FM Cardbus. Only in analog mode, live TV and captures. Any ideas?

[mdw]

I have what looks to be pretty much the same artefacts on my AVerTV Hybrid+FM Cardbus. Only in analog mode, live TV and captures. Any ideas?

Is following true for your case?
- the artifacts get wors if the scene is busy with motion
- the artifacts are prevalently along left side of picture
- the the stripes in fact reflect another part of the picture

MdW

[Jay Bee]

Is following true for your case?
- the artifacts get wors if the scene is busy with motion
- the artifacts are prevalently along left side of picture
- the the stripes in fact reflect another part of the picture

MdW

1) yes
2) don't think so
3) no

I'm not sure if it is indeed the same problem and ATM I don't have access to the laptop in question. I'll have a closer look at the issue when I get the chance. Could be a few days though.

[Boulder]

What capture settings do you use (colorspace etc.)? Have you tried moving the capture card to a different PCI slot? I recall having a similar issue with green stripes on an old AMD system with a VIA chipset (KT333A I think).

[mdw]

What capture settings do you use (colorspace etc.)? Have you tried moving the capture card to a different PCI slot? I recall having a similar issue with green stripes on an old AMD system with a VIA chipset (KT333A I think).

I use YUY2 setting, compression is Huffyuv and PCM, 25 fps.
And yes, I moved the card to other PCI slot without any visible difference. My motherboard is nForce2 based.

MdW

[Boulder]

Have you tried any other codec (such as MJPEG, there's a good quality free one in ffdshow) and have you tried disabling preview while capturing? The symptoms look like the PCI bus is having a traffic jam at times.

[mdw]

Have you tried any other codec (such as MJPEG, there's a good quality free one in ffdshow) and have you tried disabling preview while capturing? The symptoms look like the PCI bus is having a traffic jam at times.

The idea is to compress the data before they go to disc file and thus relieve PCI bus? The problem with this is CPU speed. My CPU certainly does not have the power to do on-the-fly XviD encoding, just Huffyuv consumes about 20-25%. MJPEG might be feasible, I'll try that route.

MdW

[Boulder]

The idea is to compress the data before they go to disc file and thus relieve PCI bus?
Yes. The amount of data when compressing with HuffYUV is usually 4-5 times bigger than ffdshow's MJPEG at quality 100.

The problem with this is CPU speed. My CPU certainly does not have the power to do on-the-fly XviD encoding, just Huffyuv consumes about 20-25%. MJPEG might be feasible, I'll try that route.
I wouldn't recommend you to use XviD or DivX for capturing anyway;) Disabling preview while capturing will also reduce CPU and PCI bus load.

[mdw]

Yes. The amount of data when compressing with HuffYUV is usually 4-5 times bigger than ffdshow's MJPEG at quality 100.

Hm, where do I get "ffdshow's MJPEG"? I installed ffdshow installer from sourceforge, but actually I don't see any new codecs in VirtualDub...

I wouldn't recommend you to use XviD or DivX for capturing anyway;) Disabling preview while capturing will also reduce CPU and PCI bus load.

I turn off preview for capture, but it doesn't seem to help much, if at all.

MdW

[Boulder]

Download and install a build from here : http://esby.free.fr/CelticDruid/ and it should contain a VfW portion - it could be that the old official build doesn't include it. You can then use ffdshow for capturing, it contains multiple codecs.

[jggimi]

The PCI bus gets only a partial "savings" from compression. The initial capture is of full video, which must run across the PCI bus from a PCI capture card into memory. Compressed data also has to run back across the bus to reach your IDE, SATA, or SCSI controller, and any bus bandwidth savings would be on that back end.

[Boulder]

But a saving nevertheless, and excessive HD access during capture does cause stripes even on a rather modern system:) I recall having stripes on my first capture-capable system when capturing with HuffYUV compression but much less when using PicVideo's MJPEG.

[mdw]

Download and install a build from here : http://esby.free.fr/CelticDruid/ and it should contain a VfW portion - it could be that the old official build doesn't include it. You can then use ffdshow for capturing, it contains multiple codecs.

So I tried MJPEG and it really improves the situation, though there are still some stripes present. It's quite a question what is better: to use field 1 only and eliminate all striping or use MJPEG and live with some.

Thanks for help, anyway.

MdW

[Boulder]

There are some ways to deal with the stripes but chances are that it'll look worse than choosing just the faultless field. I'd give the Avisynth filter DeSpot a try, RemoveDirt might also help you. With very light settings it could be that they only affect the stripe and leave almost everything else intact.

You could also post a new thread in the Avisynth usage forum about repairing the other field and include a sample clip.

[STC-Fan]

I've had exactly the same problem myself - with both a BT878-based PCI capture card, and another based on an SAA7134 chip. The way I eventually got around it was to, erm, use the S-video VIVO port on my AGP graphics card - wish I'd thought of that before splashing £30 on the aforementioned SAA-based card.

Anyway, I believed it to be a problem with my motherboard (an ASUS A7N8X Deluxe with nForce 2 chipset), and sent said mobo maker a large tech support query, but only to get a very insulting response telling me to check my cables & resolution, things I'd already changed umpteenth times to no avail. (And if I remember rightly, I *had* told them that I'd tried those things already, in which case a simple "sorry, we haven't got any new suggestions" response would've been fine...)

Suffice to say, the people on this forum offered far, far more intelligent solutions - granted I never did get the problem with PCI capture cards fixed, but at least some people were willing to help when those dopey staff at ASUS weren't :)

[Boulder]

One reason for me to choose a Pentium system with Intel's chipset actually was that I knew that capture problems would be much less frequent ;)

[mdw]

There are some ways to deal with the stripes but chances are that it'll look worse than choosing just the faultless field. I'd give the Avisynth filter DeSpot a try, RemoveDirt might also help you. With very light settings it could be that they only affect the stripe and leave almost everything else intact.

You could also post a new thread in the Avisynth usage forum about repairing the other field and include a sample clip.

Well, AVISynth complains, that it cannot open the MJPG FourCC. Hmm, probably time to finally learn thing or two about AVISynth.

BTW, I have the Asus 87N8X mobo STC-Fan mentions...

MdW

[Boulder]

Make sure you enable MJPEG decoding, it's in VfW codec configuration, the Decoder tab, under the heading Codecs. Set libavcodec for MJPEG and it should open just fine. By the way, if you used YUY2 colorspace, put the parameter pixel_type="YUY2" in AVISource. Otherwise you get YV12.

[mdw]

Make sure you enable MJPEG decoding, it's in VfW codec configuration, the Decoder tab, under the heading Codecs. Set libavcodec for MJPEG and it should open just fine. By the way, if you used YUY2 colorspace, put the parameter pixel_type="YUY2" in AVISource. Otherwise you get YV12.

That's exactly it, thanks a million.

MdW

[mdw]

Just for record: I recently upgraded my system with new motherboard (Asus M2N-E) and all the problems with the Aver card are gone and the picture it grabs is perfect.

-mdw