dropped frames: Could it be the capture h/w?

[SaSi]

I have an ASUS 9180V with Video in. I also have a Haupauge PC/TV/FM capture card.

When capturing with the ASUS, I get a few dropped frames (7 out of 5~6 hours continous capture).

I re-installed and tried the Hauppauge. No dropped frames in the same capture duration.

In both cases I used the same capture program and the same codecs/settings and captured on the same disk. In both cases, CPU utilization was moderate (40~60%).

Apart from the drivers that come with each board (nVidia drivers vs Hauppauge drivers), the only difference in the capture solution is the chipset on the board.

Could it be that some capture cards suffer of dropped frames just because the h/w or the drivers or their combination is bad?

[SatStorm]

nvidia chipset capture at 704 x 576/480 and resize to whatever you choose (up to 720 x 576/480)

Bt8xx chipsets (most Hauppauge cards) capture at wierd framesizes (like 688 x 576/480 for example), and resize to whatever you choose.

So: Nvidia is heavier for a system compared a bt8xx card. Count also the resizing it has to do so to capture to what we determine and you see why dropped frames appear...

7 dropped frames per 5 / 6 hours is nothing. In the matter of fact, even 7 dropped frames part half hour is unoticable!
With my nvidia card, I use to have about 15 framedrops per half hour. With my bt8xx cards (hauppauge and kworld) I have 1 framedrop per hour...
None is noticable.

[pyrohydra]

Bt8xx chipsets (most Hauppauge cards) capture at wierd framesizes (like 688 x 576/480 for example), and resize to whatever you choose.

Huh?!?! I have been capturing at 720x480 (NTSC) from my Bt8x8 card using Virtualdub. Are you saying I should be capturing at 688 x 480 to get optimal results? Or does it not really matter - especially since I eventually resize it to 352x480 anyway.

[SatStorm]

No, I don't say something like that...

Read this for more infos:
https://www.videohelp.com/forum/viewtopic.php?t=199669&highlight=

[SaSi]

Well, in terms of statistics, 7 dropped frames out of - what 1 million - is nothing. However, if I capture a VHS tape recorded at LP (8 hours long) in a go and then want to split the capture into segments, audio starts to get a little out of sync the more I step to the latter parts of the capture.

I see people complaining about dropped frames when capturing through VIVO cards. I find this to be true and something one cannot avoid with such solutions. It seems that even a high power system with plenty of space of fast hard disk cannot achieve an error free capture (at least with certain makes of capture cards).

On the other hand, capturing with an external (or internal) self-contained hardware codec (like the Pinnacle PCTV USB I use) is much better in terms of overall quality, sync and PC utilization. It even works (marginally) on a USB 1.1 laptop with PII/333MHz.

[FulciLives]

Bt8xx chipsets (most Hauppauge cards) capture at wierd framesizes (like 688 x 576/480 for example), and resize to whatever you choose.

Huh?!?! I have been capturing at 720x480 (NTSC) from my Bt8x8 card using Virtualdub. Are you saying I should be capturing at 688 x 480 to get optimal results? Or does it not really matter - especially since I eventually resize it to 352x480 anyway.

It all depends on the drivers.

I found that my BT capture card can only give a proper aspect ratio if I capture at 688x480 using the official drivers.

I have an AverTV Stereo with Avermedia drivers (Avermedia is the company that makes the AverTV Stereo).

However my AverTV Stereo can capture 720x480 using the BTwincap drivers. Actually it has been shown that even with the BTwincap drivers you have to capture at 712x480 for a proper aspect ratio but 720x480 is close enough so that the aspect ratio really isn't thrown off at all.

For a while I've been using the BTwincap drivers capturing at 712x480 ... I then crop to 704x480 then pad it back up to 720x480 ... this helps to get rid of some of the "junk black" on the edges.

However I found for me that the default BTwincap driver settings for things like color saturation, brightness, contrast etc. were WAY off and I always had to fiddle with them and it's really hard to tweak it to JUST the right amount since NTSC video looks so different on a computer monitor VS a NTSC TV.

As a result I've switched back to using the Avermedia drivers because the default settings for the picture look just about perfect. So I capture at 688x480 then pad it up to 720x480 for Full D1 resolution or resize from 688x480 to 344x480 and then pad it up to 352x480 for Half D1 resolution.

You are missing a lot of picture information at 688x480 but the missing picture information is not seen anyways due to normal TV overscan although I wouldn't be suprised if some high end TV's just barely show a hint of the black since the higher end TV's may have less TV ovescan than a normal TV.

One way to test this ... and I did this mysef ... is to RIP a DVD to your HDD and do a screen grab from a scene using VirtualDub etc.

Then capture same scene from that DVD using your capture card and try 720x480 as well as 704x480 as well as 688x480 etc.

Then do a screen grab from your capture (again using VirtualDub for instance) and compare it to the one from the DVD rip.

Now you can see how close your capture is ASPECT RATIO wise to the original RIPPED unaltered DVD.

- John "FulciLives" Coleman

[FokeyJoe]

Going back to SaSi's original post... I don't think res is an issue because the same proccy usage would indicate that roughly the same amount of data is being passed through.

You don't specify much about the Hauppauge, so it's difficult to gauge the differences. Are we talking hardware encoder vs not, DVB vs. analogue, PCI vs AGP?

I wouldn't expect your Asus card to drop frames at all, particularly if it's an 8XAGP (well phat!). If you read the frame drop sticky, I think the relevant quote to bear in mind is: "A manufacturer wouldn't release a card that dropped frames all the time". What a convenient way to blameshift!

nvidia drivers could well be a problem. My Asus V7700 won't even capture on any drivers other than a particular old version. I advise you ask other 9180 owners about the drivers they use, so you know some that at least work for others. Also bear in mind that the nvidia drivers can be quite heavy-duty for no sake at all.. they implement their own crossbars and things. This can interfere with other capture drivers (as they did with my Avermedia PCI EZMaker) - though that would suggest that the Hauppauge should be the one dropping frames.

HTH

[SatStorm]

When virtualdub and mainconcept 1.4.2 drop frames, they also drop audio frames, so the audio / video is always in synch.
VirtualVCR and Virtuldubsynch, try to adjust the audio (dynamic resampling or whatever). This works only if you have problems because of the different clock of your capture card and your audio card. If the reason is not there, this feature is useless.

With my Asus 7700 I have to use only wdm 1.08 to make it capture at win2K. If I use mainconcept to capture at 720 x 576 and encode realtime at 352 x 576, I have droped frames because both drivers and mainconcept are heavy for my athlon 1.700XP (my dedicate for capture PC). If I use 704 x 576, I don't drop frames. The problem is that because of a bug inside mainconcept, you have a statering at the bottom of the screen (like a field distortion), if you capture less than 720 x 576 and resize to whatever and at the same time you convert reatlime to mpeg 2.

This hobby has countless issues to deal with....

[pyrohydra]

Thanks for the tips folks! My apologizes if I threadjacked.

[SaSi]

When virtualdub and mainconcept 1.4.2 drop frames, they also drop audio frames, so the audio / video is always in synch.
VirtualVCR and Virtuldubsynch, try to adjust the audio (dynamic resampling or whatever). This works only if you have problems because of the different clock of your capture card and your audio card. If the reason is not there, this feature is useless.

This hobby has countless issues to deal with....

Well, Satstorm you are certainly correct in your conclusion.

What I found out with MainConcept's capture feature is that if I capture to MPEG-2, with audio and video muxed, audio sync is not lost no matter how many frames are dropped. I tried to capture during heavy CPU load and had 20-30% dropped frames. Not viewable, of course, but no audio/video sync problems.

Capturing to AVI is a different thing. It depends on codecs (?) and capture application (??).

Can't give any conclusions, but capturing with DIVX5 for video and no compression for audio will generate a sync problem if frames are dropped, both with Mainconcept and VirtualDUB.

In any case, my finding (call me a heretic if you wish), is that the current capture h/w is not mature enough for trouble free results. The kind of results you get when you press REC on your VCR.

I am certain that I can get my problematic Pinnacle PCTV deluxe (!!) capture device to work properly with a certain combination of OS (W2K or XP) Service Pack and/or DirectX (8, 8.1, 9?). Otherwise, I guess, Pinnacle would not have released the product.

The same applies to the Hauppauge card. It worked fine under Windows 98 which was not terribly useful when capturing a 80Gb file. Switched to Win2K and the drivers simply didn't work. Newer drivers may work now better but I now use XP.

In 2 to 3 years, we will, probably, be able to really through away our VCRs and use a PC instead. Until then, when I schedule a recording, I also schedule the VCR (for backup).

[vhelp]

Well, I too am experiencing problems.

However, ever since I installed a Winfast TV-2000 XP "Expert" card into my
system and installed the WDM driver that came with it ( had lots of problems
before it started to work though ) I've not had any dropped frames.
But, I have not actually capture an hour's straight, because of my W98 and
it's FAT32 limit of 4gig. If I let it go past the 4gig, my capture app crashes
out at that point.

Under my Windows 98 Gold version:

* I'm using Virtual VCR v2.6.9.6252 and so far, it does not drop frames.

I do notice that it has TWO "frame drops" fields under the Capture section.
Labeld: Dropped, and Dropped 2.
My guess is that it supports multi-segmented captures, for this. But, so far,
I have not seen any reference to segmented captures. If anyone knows
what I'm missing, please point me to the right area - thanks.

Back to topic...

I'm using virtual vcr w/ my LD player. I also hook it up to my TRV22 cam.
If I can just get past the 4 gig limit, I wold also like to see if it drops frames
past the 4 gig limit for my own curiosity.

But, this card so far, does not seem to drop frames w/ it's WDM driver,
under my XP-1700 CPU chip.

And, FWIW, my 2nd 20gig HD is heavily loaded w/ tunes of files, and I'm
always down to 4-8 gigs in my multi-tests scenarios that I perform every
day

I hope you figure out your "drop" issue 8) and let us know what the actual
cause was.

Good luck,
-vhelp