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MrTibs 11-06-2003 11:35 AM

Help with my hardware - dropped frames while recording
OK, I can't seem to capture at full resolution without dropped frames.

Her is my system:

AMD 1400
128 MBRam,
50 Gig 5400 RPM
20 Gb 7200 RPM
Capture card: Matrox 400 TV
Capture software: VirtualDub-sync

The Matrox HD speed test tells me that my 50 gig tops out at 20 Mbs while my 20 gig only hits about 18 mbs. Capturing at full resoution with huffy or Picvideo is about 19 mbs.


1. Are these values normal?
2. What kind of throughput should I get on my harddrives?
3. What are your suggestions to "optimize" my system.
4. Suggestions....

Boulder 11-06-2003 12:01 PM

1) If you have installed any IDE drivers for your system, get rid of them and use the one that Win98 installs by default. It's actually better to use DMA instead of UDMA in Win98 :!: The processor usage should be lower even though UDMA states that it consumes less CPU power than DMA.

2) Disable any background programs that may interfere.

3) Check your BIOS settings. Try raising PCI latency to 64.

MrTibs 11-06-2003 02:19 PM


Thanks for the suggestions, I'll try them tonight.

What do you think about the HD throughput? It is low considering the hardware?

Boulder 11-06-2003 03:45 PM

Hard to say, I don't remember what kind of throughput I got when I had an older HD on Win98. Your disks should be fast enough, however. PicVideo MJPEG at 19 takes around 4000-7000KB/s on 704x576@25fps, depending on the source. Do you use YUY2 colorspace?

You could also try defragging the HD you use for capturing :idea:

MrTibs 11-06-2003 05:01 PM

I nomally use YUY2 when capturing and my "faster" of the two drives is my main drive.

I poked around and it seems that I shouldn't have my two drives on the same IDE chain. I'll change that with your suggestions and try again.

Have you or anyone else tried using some ot the other lossless codecs for capturing? (VBLE, Loco, ffv1, ...)

Boulder 11-07-2003 05:39 AM


Originally Posted by MrTibs
I poked around and it seems that I shouldn't have my two drives on the same IDE chain. I'll change that with your suggestions and try again.

This shouldn't be a problem, hasn't been in many years I think.


Have you or anyone else tried using some ot the other lossless codecs for capturing? (VBLE, Loco, ffv1, ...)
The only lossless codec I can recommend is HuffYUV. The others are very slow to decompress and using YV12 colorspace is not a good idea when capturing (chroma upsampling errors may occur, rounding errors etc.)

MrTibs 11-07-2003 02:17 PM

I tried everything and still no luck. VDub tells me that 704x480 at 30fps takes about 18,000 mbs. I believe IDE drives can only have a sustained 10K mbs.

What is everyone else doing? Who can capture to Huffy at 704x480 at 30 fps?

Boulder 11-07-2003 03:15 PM

That's what it requires uncompressed. You'll see the actual values changing in the status area, they should be changing all the time as some material (for example a very dark picture) will compress better than others. HuffYUV often gains compression from 1.5 to 3.0:1.

What is the highest resolution which doesn't result in dropped frames?

What drivers are you using, are they VfW or WDM?

MrTibs 11-07-2003 05:02 PM

The Matrox only offers resolutions lite 352x480 or 704x480. It doesn't seem to work with odd resolutions so I'm left trying compression to determine the maximum data throughput. (I believe I was looking in the status area but I'll test again tonight.)

I believe I'm using VFW (I'm not at my home computer right now).

I guess, what I am asking is "can" I get what I want with my existing hardware? I do have a couple of 10 gig SCSI drives I could hook up to a RAID controller but that still limits me to 20 gig of storage. (i.e. there is no point in buying a new 120gig IDE drive...) I also may try installing my AverTV capture card since it has more options...perhaps it will work.

What do you use boulder? Kwaq?

Edit: I just went to and he has quite a detailed page on the subject. He also mentioned Vdub's benchmark program which I had forgoten about. I'll check all of that out and get back to you.

kwag 11-08-2003 02:08 AM

Re: Help with my hardware - dropped frames on a 1400!

Originally Posted by MrTibs
3. What are your suggestions to "optimize" my system.
4. Suggestions....

Hi MrTibs,

Go SCSI :!:
Get a Cheetah (10,000RPM) drive, and you won't have any problems.
Or you could try an external 7,200RPM drive, connected via FireWire.
But the best setup is SCSI drives. The SCSI card will have a low impact on your computer's I/O, and and you'll barely loose frames.


Boulder 11-08-2003 05:00 AM

Nah, you don't need a SCSI drive to capture :wink:

Have you tried raising the buffers in VirtualDub? (I read your post at D9) I think that I put 100 for video buffers, 10 for audio and audio buffer size 36000.

Currently I have a P4-2800/120GB and a 7200rpm HD for capturing, but I used to do captures with a TB-1400 and a 40GB 5400 drive. No dropped frames whatsoever.

IIRC, some Matrox cards have a hardware MJPEG codec. Does your card have one? Maybe you're actually compressing twice, once in hardware (MJPEG) and the second time in software (HuffYUV) ?

kwag 11-08-2003 01:13 PM


Originally Posted by Boulder
Nah, you don't need a SCSI drive to capture :wink:

Well, for slow machines, it really helps :!: :D
But there's another choice, which will let you capture real-time straight to MPEG-2 even on a slow PII, and takes far FAR less disk space than the Huffy CODEC ( or any other lossless CODECS ) :idea:
Get a Haupagge WinTV PVR-250 or 350, and you can capture at 720x480 full D-1 at up to 12Mbps.
This will be "blockless", because of the high bitrate.
Then you can re-encode to anything you want.
That little PVR card is a jewel :cool:


incredible 11-08-2003 05:34 PM

Sorry, but ...

First, ist it a Matrox G400 TV????
(I just checked at Matrox and I only could found a G400 TV)
Cause if yes, Boulder is right and you can enyoy onboard MJPEG hardware encoding which blows away your problems!

Second: Before investing money in SCSI components or a new capture card ... we should see if its worth to invest money in such components IF you want to buy something new ;-)

Because: If you gonna buy a PVR 250 (I think about 150 Dollars) ... your machine will still be very slow and so anyway... very soon you will invest in a new CPU, a new Mainboard and so on. Even using SCSI won't beware you of the needing refering to new hardware in the near future.

So ... my recommendation IF you gonna buy something:
Stay with your capture card and by a new CPU (maybe a XP2400+) and also a new Mainboard(if its really needed!), therefore you will obtain a lot of power ressources which will give you a wonderful performance advantage. And your HDs should be big and fast enough so you won't need no new ones in the near future.
These Things (CPU + Mainboard) will also cost about 130 Dollars.
Cause by doing this ... you also will get in addition a fast encoding machine, ... no dropped frames refering low CPU power when still using your existing card, .. still using your capture card (MJPEG Codec as Boulder also mentioned) and so on.

Sorry If I "interrupted" your hardware recommendation Kwag, but I think by choosing the "new CPU+Mainboard"-way .. he will get in addition some other advantages.

And after some time passed by I also recommend to switch to a PVR 250! ;-)

MrTibs 11-08-2003 07:39 PM


Yes it is a G400 Tv and yes it does have on-board MJpeg encoding. (Which is why I bought it.) However, the quality of the MJpeg encoder is crap. At higher resolutions I get a checkerboard pattern all over the place. I have been able to produce pretty good results but I end up doing heavy filtering.


Thanks for taking the time to consider my problem. I have been watching the PVR 250 on ebay for some time now. I knew that you had one and highly recomened it so I knew it is good. As soon as I can gather the money for it ($200-250 Canadian) I'll pick one up.


Thanks again for your help. I did try you suggestions and the situation definitly improved but still I'm dropping about one frame a minute.

@ all of the above.

Although I agree the my machine is slow at 1400, it seldom goes above 50% when capturing so I don't think a faster CPU will do much.

I did try Avi_io with excelent results. Not only does Avi_io capure without frame loss but it allows me to capture in 480x480, 528x480 and 704x480. I haven't done a long test yet but I seems pretty good. This result confuses me because I know that both Vdub and AVI_IO are VFW programs and Vdub has done very well on my other machine. (I did try VirtualVCR because it is a WDM program with good results but it was pretty unstable on my system.)

BTW, I also tried adding memory but it didn't seem to have any effect at all.

Thanks again everyone. Feel free to offer more suggestions should you think of any.

vhelp 11-09-2003 01:17 AM

@ MrTibs..

The best tip I can give ya, is don't start debugging w/ VHS sources. You'll
get nowhere's from it !!
Yeah, NEVER start w/ VHS. NEVER :wink: !!

Start w/ regular sources like Cable or Satellite. These are better sources.
VHS has too many issues. Mostly the VHS tapes itself. And, you could
rupture a groin muscle when going in the wrong direction :roll:
I know, as I've ben their.

Once you figure out your issues w/ framedrops (ie, improvements) while
using cable or satellite. Should you feel you've gotten to the point of a
comprimise, then go on to VHS and work out your issues. You'll find (or
learn) that it could be the source tapes (or your vcr) Anyways..

I'm glad you got it working better under AVI_IO. I was gonna suggest this
earlier today, but I got tied up w/ an IVTC project I've ben working on for
quite some time (and nailed it shut) :) anyways..

But, there's no reason why you can't get 720x480 captures and w/out (or
minimal) framedrops. My XP 1700+ does ok, but drops frames. But, on
my XP 1800+ I don't drop any frames. I'm also using the same mobo on
both these pc's. But, my 1800+ has a rev 1.2 bios while my 1700+ has a
rev 1.0 - - so there must be some changes that took place on the rev 1.2
mobo and explains why I get better performance. And, no, the slight increase
in cpu speed is not the reason.
However, the sound card is another culprit to look into. After replacing my
old SBlive 5.1 card some time last year, I got better performance. These
cards steal system resources and hidden timings or cycles, which causes
your framedrops to occur more.

Anways, I'm pushing beyond my limits here, as I got lots of projects cooking
on the stove, and it's already past 1am here, and I'm pooped :)

Good luck,

kwag 11-09-2003 01:40 PM

@MrTibs ( an all )

Here's a PVR-250 sample, for your evaluation ( and collection :D ).
Here's my first capture ( actually a manual recording test ) done with MythTV and my PVR-250 via Composite video.
Please note that even though the capture is 720x480, the actual channel (digital broadcast) I recorded from, is not a 720x480 transmission. It seems more like 480x480 (which probably is just that!)
However, the sample is completely blockless and artifact free, which clearly shows the quality of the hardware encoder chip in the card.
The sample is MPEG-2 interlaced, so preview it with PowerDVD or WinDVD. Is you use WMP, you'll see the interlacing.

Edit: The machine I'm testing MythTV, where I did the actual capture, is a Pentium III @500Mhz with 128MB RAM :lol: :hihi:
So you can see what to expect from this card, even on very slow processors :cool:


MrTibs 11-09-2003 03:07 PM

Yup, that works for me. I think I'll get rid of my Matrox ASAP.

I think you should start a forum on MythTV. I've been meaning to build one for some time but... who has the time :wink:

BTW, are you removing that logo? If so, how?

incredible 11-09-2003 04:10 PM


Originally Posted by Kwag
Is you use WMP, you'll see the interlacing.

But that's what counts! The original condition! :D

And as I already know this card its awesome! Block-Free interlaced encodings 8) And I also saw some other card-based high bitrate hardware encoded streams in interlaced condition which seemed like big "basura" in comparison to this.

BTW I've some nice PVR250-AVS scripts in case of noisy interlaced and progressive captures, so if you like ...

kwag 11-09-2003 08:56 PM


Originally Posted by MrTibs
Yup, that works for me. I think I'll get rid of my Matrox ASAP.

:lol: :mrgreen:

I think you should start a forum on MythTV.
Done :!: ;)

I've been meaning to build one for some time but... who has the time :wink:

BTW, are you removing that logo? If so, how?
No, I didn't remove the logo on that clip. That's a native, un-edited capture :)


MrTibs 11-10-2003 05:39 PM


I realize that the logo is there, I was wondering if you intended to leave it there and if not, what tools you use to remove it.

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