Lousy capture quality with VirtualDub

[Darklord]

Okay, I downloaded the latest version, then went to the guides over at VCDHelp to give it a test.

My capture was lousy.

I was watching the capture progess, and frames dropped was almost 50% of the number of frames captured.

trying to capture at 720 x 480, set cd quality audio, Huffyuv code, 29.97 fps., lock video stream to audio, boom. frames dropped left and right.

Troubleshooting suggests to slow a processor.

I am using 2ghz, 1gb ram, nForce2 motherboard. It's plenty fast. The WinFast PVR capture utility that comes with the video card works just fine. Output video is perfect.

Any ideas where to start?

[Koepi]

Yes, i have:

head over to the capture-forum and read the FAQ.

Regards
Koepi

[Darklord]

I might have found that useful if I hadn't already read the guides first.

[Wilbert]

Did you select UYVY as color format? Did you enable the dma of your harddrive? Is your harddrive 7200 rpm?

[Darklord]

On the first question yes. On the second, I am using 10K speed SCSI drives.

I had been going through the guides experimenting BEFORE I asked. The problem was every setting I used got the same results, even when I followed the guides suggested settings 100%.

However I can capture perfect MPG2 captures using the the WinFast software that came with the card so I don't see how it could be a hardware problem.

[ivan_alias]

Which TV card is it?

If your is compatible try these drivers:

http://btwincap.sf.net

[Darklord]

it's a GeForce4 Ti4600. First test were with the included capture software at "Capture DVD" setting, which was 720 x 480.

I just grabbed an alternate VirtualDub program that supposedly doesn't drop frames and will try that later.

[kempodragon]

Looking at your settings, I can think of one problem already. "Lock video stream to audio" causes nothing but trouble. Instead, go to the capture tab, and open up the timing button. Check "Adjust video clock dynamically to match audio clock". It will solve a lot of synch issues due to the audio and video clocks not matching exactly. Next, during the capture, watch the two numbers at the right of information panel. At the start of the capture, they will look like this: 0/0. The left number is the number of video frames dropped from the video, the right is the frame dropped due to audio synch. The dropped video shows up in the file info of the captured avi, while the audio drop doesn't. Watching these two numbers can help identify where the problem is.

[Darklord]

I didn't use the lock video stream to audio at first, I did later as I saw it mentioned in one of the capture guides.

I do not see 0/0 anywhere on the information panel in the version I am using, 1.4.12

I made the changes you suggested, un did the lock video stream, and made sure that adjust video clock dynamically was selected.

I did a test capture and I still get almost 50% frame loss on the capture. The only thing that reduced the frme dropping was to slow the capture down to 15FPS, which looks awful.

Note that I have read each and every link in the capture FAQ regarding using VirtualDub.

And as I have stated before, I have no problem doing full on MPEG2 capture.

[kempodragon]

The two numbers come right after the spill seg#. Make sure "Show information panel" is checked in the capture options. Some other things to improve your captures:
1. Use a dedicated hard drive for capturing. You didn't mention if you are using your system disk. I was using my system disk until recently. After I installed a second hard drive on it's own master slot, I saw my capture ability jump almost twice as much. With my system disk, the most I could capture in MPEG or AVi was 352x480. After I installed my second hard drive on a Promise IDE card, I was able to capture 720x480 uncompressed, and 640x480 Huffyuv. MPEG2, I was able to capture full DVD-spec.
2. If you're using Win2k or XP, the WDM-VfW wrapper is known to be buggy. The VirtualDub website mentions this and the fact that it will increase the cpu load.
3. If you've got the hard drive space, capture in uncompressed YUY2 colorspace and uncompressed audio. Capping uncompressed puts the least load on the system. Next try MJPEG. While it is a lossy codec, the highest quality setting is on a par with Huffyuv, and it is very fast. Huffyuv is lossless, so the cpu load is greatest.

[Darklord]

Okay this is where I am getting confused. Is there really that much of a difference in visual appearance between versions of this?

I have show information checked, but I don't see anything that says spill seg.

I have frames captured, total time, time left, total file size, disk space free, cpu usage (which was pretty low), then below that were the boxes for video which has size, average size, data rate, compression, vg. frame size, frames dropped and then

audio which has size, relative rate, data rate, compression and VT Adujust.

I am copying to a secondary drive used only for data, using W2K.

I still have not tried any of the alternate versions ov VDub yet, I'll be doing that later tonight I hope.

[ivan_alias]

If you are using WDM drivers try http://www.digtv.ws

Its a simple app, but works well for capturing.

[kempodragon]

The numbers are at the bottom of the screen, below the incoming video. The letters are in small font size, so it is easy to overlook. AFAIK, this has been present in all versions

[Darklord]

Ok, I'll look closer later.

Just out of curiosity, is there some compelling reason I should capture as an AVI and then convert to MPEG, vs. capturing MPEG2 in the first place?

I noticed there was an MPEG2 plugin for VDub. My system seems to capture MPEG2 with no problems.............

[ivan_alias]

If you're happy with the quality of the mpeg2 you get then I'd stick with that and compress to mpeg4 later, however you will get better quality by capturing to full resolution with a lossless codec such as huffyuv and then compressing to mpeg4.

The problems you are getting with vdub may be any of these:

drivers
vfw - wdm wrapper
configuration of vdub.
nvidia problems - read up on this in the forum

If you want the absolute best quality, you need to do umcompressed capture then compress with the filters you prefer. You may find that vdub just doesnt work for you in this case, try another capture app. If you are happy with the mpeg2 you get then stick with it, weather you keep it as mpeg2 or compress to mpeg4 is entirely up to your taste - and disk space!

[Darklord]

Originally posted by ivan_alias
If you're happy with the quality of the mpeg2 you get then I'd stick with that and compress to mpeg4 later, however you will get better quality by capturing to full resolution with a lossless codec such as huffyuv and then compressing to mpeg4.


The problems you are getting with vdub may be any of these:

drivers
vfw - wdm wrapper
configuration of vdub.
nvidia problems - read up on this in the forum


not sure about drivers since I just don't have the experience yet. WDM wrapper certainly might be likely considering the advice I am getting. Not sure on VDub congiguation though as I have copied guide settings from various sites including Luke's video, vcdhelp and here, and get the same results.


If you want the absolute best quality, you need to do umcompressed capture then compress with the filters you prefer. You may find that vdub just doesnt work for you in this case, try another capture app. If you are happy with the mpeg2 you get then stick with it, weather you keep it as mpeg2 or compress to mpeg4 is entirely up to your taste - and disk space!


Now this last part is where I am slightly confused. I can make SVCD's or DVD's from MPEG4? I thought they needed to be mpeg2?

[chemmajik]

You never mentioned at what compression or quality ratio you where choosing when using huffyyuv? You maybe trying to compress to much. Also some systems run better by using the PicVideo MJpeg codec instead if Pegasus still has it available. I'd try a simple 2:1 to 4:1 compression for starters till you can get it to not drop frames.

[Darklord]

when configuring the Huffyuv there was 2 boxes, predict median and predict gradient. I selected best for both.

[ivan_alias]

Now this last part is where I am slightly confused. I can make SVCD's or DVD's from MPEG4? I thought they needed to be mpeg2?

Sorry I didn't mean to imply that. I keep my backups as MPEG4 (Xvid in my case). I don't make any DVD or SVCD, they are of course MPEG2 streams only!

Any luck with other caputre apps or other codecs like MJPEG ?

[Darklord]

Originally posted by ivan_alias
Any luck with other caputre apps or other codecs like MJPEG ?


The only other proggie I have tried is the WinFastPVR that came with the video card.

I get perfect crisp captures as MPEG2.

In fact, the software has other modes, it will allow me to select video resolutions (computer), VCD, SVCD, DVD and a couple of others. They all capture beautifully.

[Dermir]

Well - you wrote "I was watching the capture-process".
Have you tried capturing with preview/overlay OFF ? That might solve your problem.
Or did you want to say "I was looking at the stats Vdub displays when capturing" ?

[TheInformer]

I agree with Dermir.

I'm at work right now and don't have access to VDub to look at, so please excuse the lack of conciseness!

In one of the menues there is an option to Enable DirectDraw acceleration for both fields. Do it.

In another menu there is an option to Hide Capture while capturing. Do it. You'll have to rely on the audio to start/stop though.

Try those two options and let us know what happens.

[fisix]

Originally posted by Wilbert
Did you select UYVY as color format? Did you enable the dma of your harddrive? Is your harddrive 7200 rpm?


um, why would you want to choose uyvy? i thought yuy2 was the most appropriate.

-fiz

[Wilbert]

Yes, but you can not always choose that.

[Dermir]

Well, if he indeed chose uyvy instead of yuy2, that should not cause any trouble, because uyvy needs a bit less cpu than yuy2 and loses an unnoticable bit of quality in comparison, so it's almost equal.
Or should he then use the colour-fix for DirectX8.1 for huffyuv (if that fix repairs any other things than colour problems)?