Capturing 768x576 Generates Unwanted Lines!

[muratremix]

I dont know how to explain that. But when I capture 384x576 or 768x576 full screen with iuVCR or Avermedia's own program, I see some lines fuzzing around screen sometimes. Usually when screen changes a lot (ie. fast action movie)

I use AverMedia Phone 98 w/VCR. Using latest Aver drivers (but I also tried iulabs tweaked bt878 drivers too. Didn't fixed my problem...)
I can't install BTWINCAP drivers, but I'm not sure it'll fix things. Therefore with BTWINCAP you can't use tv card's program.

I know Aver provides best bt878 drivers, unlike prolink (my previous tv card). But WTF ? Why I can't capture 768x576 without any corruption?

I was happy, when I see no frame drops on my Athlon 1000 / 384 Ram / 7200 Quantum ATA100 HDD

Has anyone know the fix?

[muratremix]

Here is the sample pictures (40Kb each)
First frame is corrupted by something.
Second frame is normal.

[LanceSteel]

I dont know how to explain that. But when I capture 384x576 or 768x576 full screen with iuVCR or Avermedia's own program, I see some lines fuzzing around screen sometimes.

I know Aver provides best bt878 drivers, unlike prolink (my previous tv card). But WTF ?

I guess I don't see the fuzzy lines you are talking about. I can see the error lines on her stomach in picture1 but picture2 looks good to me. I think you are talking about scanlines. Scanlines/interlacing is normal.

Read this: http://www.lukesvideo.com/interlacing.html

Look at the pictures that he has on that page and compare them to what you are seeing.

[muratremix]

Thanks for help. I tried to de-interlace captured videos with Tmpg while encoding. I never selected Odd field as de-interlace.

I just tried again Only Odd field (adaption) worked, rest produces corrupt picture. Holy shit!

I'll do more tests about it. Lets see if its only scanlines problem

[LanceSteel]

Thanks for help. I tried to de-interlace captured videos with Tmpg while encoding. I never selected Odd field as de-interlace.

Wait a minute. Is the final format of your encode going to be DVD, SVCD or VCD? If its DVD then leave it as interlaced. VCDs are not interlaced and I'm unsure about SVCD. Anyway, my point is that you may not have to deinterlace it.

[muratremix]

This is just a frame grabbed with Virtualdub.
capture.avi -> picvideo MJPEG quality 19

interlaced I think. But why some channels (Analog CableTV) have more scanlines, while some other channels doesn't have.

as you see scanlines appear sometimes.
but with other channels like NBC Giga.de have scanlines always.

[muratremix]

@Lancesteel

I tried another capture. A short clip from MTV
I loaded into tsunami mpeg, open deinterlace filter and look around.

Odd field works usually. But not at some frames.
Even - odd field works much better, but there is still scratches.

it seems one filter is not enough to clear this shit.

Also I wonder if resolution decreases to half, when I de-interlace with such methods (even odd field) ?

[muratremix]

I tried some virtualdub deinterlace filters. No success
Also, theese scanlines appear sometimes on even field, sometimes on odd field. So whatever filter I choose (on tmpg) I still get fuzzy lines on some screens. Also If I choose even field or odd field, resolution reduces by half (576 / 2 = 288)
So I choose Double adaption or Even - Odd field usually
But theese options double fuzzy lines amount

[HAGGARD]

muratremix...

The explanation that some channels do have scanlines and others don't, is not the channels themself, but the movie material what they are broadcasting!!! Normaly TV signals (eg. from videocamera's) are recorded/broadcasted with interlace... BUT, if a tv station broadcasts a motion picture it is ALWAYS progressive!!! NOT that the signal is progressive (your tv still displays an interlaced signal) but a motion picture (that's why it is called motion picture) is bases on 25 frames/second (eg. like 25 photos shot in one second) Your television though is able to display 2x25 halfframes/second. So it is able to fake you that you see 50 frames/second!!!
Because a motion picture only has 25 frames/second, your television displays a single motion picture frame twice!!! In other words... the actual frame of the motion picture is first displayed as the first halfframe and then as the second halfframe on your television. Between these halfframes the motion picture doesn't advance to the next motion picture frame (No movement) so you don't see any scanlines!!!

That's why compressing interlace sources is more difficult for an MPEG encoder than progressive sources (needs more bitrate!!!)

Hope that explaned your question!!!

'HAG

[muratremix]

Thanks Haq

But I can't use my captures due to that error lines.
They appear on even field or odd field sometimes.
So even if I use 352x288 , I still get error lines sometimes
That sucks. Avermedia should do better than this.

[dphirschler]

I've had that very same problem before and I can tell you exactly what it is. The lines are left over from previous frames. They are left over because your harddrive cannot keep up with the capture. Here are some things that will improve things:

1. Use a good compression codec such as Picvideo Mjpeg. Better compressed frames means less work for your harddrive.

2. Use 16 bit color mode. I don't know why, but it looks bad while capturing, but the capture is fine when you check it out later. But you gain some speed improvement here too.

3. Of course you can reduce the horizontal size of the capture.

4. This solved the problem for me for good. Hook up your capturing harddrive on another IDE card all by itself (or at least with another fast harddrive). The problem before was that the harddrive was not allowed to operate at speed because it was limited to the speed of the slowest device on the IDE controller, which in my case was the Sony DVD burner.

5. If you still need more speed, then you may want to consider a RAID array.


Darryl

[muratremix]

Thanks dphirschler
I changed desktop color to 16 Bit
and changed compression 16 in Picvideo (it was 19)
I captured a small video, looks like it doesn't have any error lines!
good, I'll try capture a bigger video and test it.

Thanks for your help!
btw: do you know how to get better audio capture with iuvcr ?

[muratremix]

Problem solved thanks to dphirschler
I just changed desktop color to 16Bit. it was 32Bit.
I'm still using picvideo mjpeg at quality 19 (huffyuv is not avaible in iuvcr ( )
no error lines

I also test de-interlace it with Even - Odd field filter in tsunami
Result: Perfect!

[dphirschler]

It's been a while since I tinkered with the settings. I know I played with just about everything trying to get a little more speed out of it. Early on I had suspected it was caused by the video card's inability to refresh quickly enough. It was the harddrive though.

Anyways, I believe my desktop settings are either 24 or 32 bit. I set 16 bit color for the capturing (within Virtual Dub, or in your case iuVCR). And it doesn't look good during capture. You can see color banding everywhere. But when you review it later on in Virtual Dub, it looks fine.

My point is, I think that 16 bit color for your desktop is unnecessary (and may actually be slower), but setting it within the capture program speeds it up.


Darryl