WDM vs VFW capture

[McQuaid]

Yes, vfw is dead tech but is it still the best tech?

Now of course, on paper it is definately not the best tech, but in practice it's another story. This is due to the applications. Ignoring using btwincap, you must use wdm apps for wdm drivers to capture at full resolution.

Now maybe the situation has gotten better, but last year, I tried the wdm drivers for my zoltrix tv genie over the vfw ones. I tried every wdm capture program I could find and all of them had a problem with audio sync. Now, you might say that you have not noticed any problems with audio sync but please try this test. Capture in your wdm app of choice and load the file in virtualdub. Go to video/frame rate option in the menu. Do both fields say 29.97? Meaning the no change field and the 'change so video and audio durations match'. Every application failed this test whether it was vfw or wdm application except one: AVI_IO. Even virtualdub itself when used for capture fails this test and Avery Lee addressed this in a usenet thread awhile back.

Now again, you might say 'I've never noticed any sync issues so it's fine'. Well that might get you by for mpeg4 encodes but if you want to encode vcd or svcd/dvd, frame rate matters.

I'd like to hear this issue have been resolved with wdm apps but AFAIK, only one app correctly captures.

[^^-+I4004+-^^]

>I tried every wdm capture program I could find and all of them had a problem with audio sync.

same here.................

it's interesting that avi_io and vdub are vfw progs that use wrapper on wdm systems..........
(and in my view avi_io is as lousy as capture prog gets....)
recently i captured with atv2000 and it worked ok,but i didn't go over 30' at a time........
the captures passed your vdub test,but i don't see this test as to orelevant.....probably it's just info form avi header or so...

>Ignoring using btwincap, you must use wdm apps for wdm drivers to capture at full resolution.

why "ignoring btwincap"?
it's the wdm driver.....and i can capture with it in VDub (in win2k) at full res.

but i agree that there are no good wdm capture progs that worked on my system..i do most of the capturing in vfw (win98)

[bofw3]

Originally posted by ^^-+I4004+-^^
but i agree that there are no good wdm capture progs that worked on my system..i do most of the capturing in vfw (win98)

Have you ever tried Media Player Classic (MPC), the only problem I get with this one is that I can't get it to capture the audio to the AVI file, it can however capture to a separated WAV file :-(

[BaronVlad]

Capturing with MPC ? Interesting idea :D

If you dont have XP running you can use WDM drivers by installing the wdm vfw wrapper (-> FAQ)

It comes with XP and I dont have any probs with this and VDub. But sometimes the image seems to be more clear with 98SE and vfw.

[^^-+I4004+-^^]

and the "only" problem for me is that i don't even see the "record" button on my 800x600 desktop!

but the program itself doesn't matter much.(program is just a gui for the system itself.).....what matters is the underneath principles of wdm,for me it's a no-go yet........
the segmentation issue for FAT32 is not solved either....(yeap,i still need my FAT32)

[BaronVlad]

:D

ivo and his computer...

800*600 and FAT32...;)

[bofw3]

Originally posted by BaronVlad
Capturing with MPC ? Interesting idea :D

It works most of the time, File/Open Device


If you dont have XP running you can use WDM drivers by installing the wdm vfw wrapper (-> FAQ)


I know that, I even use it, it's the only way with ATI's, but there is no wapper for DirectShow Codecs :-(

[bofw3]

Originally posted by ^^-+I4004+-^^
and the "only" problem for me is that i don't even see the "record" button on my 800x600 desktop!


:-D I can't use 800x600 with 21" :-D

but the program itself doesn't matter much.(program is just a gui for the system itself.).....what matters is the underneath principles of wdm,for me it's a no-go yet........


Yes, but the worse is that WDM adds complexity without a tangible value :-(


the segmentation issue for FAT32 is not solved either....(yeap,i still need my FAT32)

Yeap, and that one also, but I use NTFS, so I don't have a problem here...

Actually what I was trying to do was use the MS DV codec, to capture in DV... but I reverted to use Mainconcept in Vdub...

[BaronVlad]

I will give MPC a try when I got my cables back. Without it crashed somehow...

Thanks for the advice bofw3 :)

[begu]

Well, I use gf4 card's TV in. The nvidia drivers are quite bad, because they ahve random field phase problem. (sometimes I have to use v'dub filter called 'field delay' and delay top field to correct the interlaced movement displayed on TV) However the image quality is very good indeed.

There is no other driver than WDM for gf cards. I use old WDM to avoid white box over the image when the source contains macrovision.
I capture with virtual dyb sync (modification) which has routines to adjust audio sample rate to maintain av-sync. I suppose it uses VFW-WDM wrapper but I still can capture in full PAL res (720x576) and 25 fps. I never drop a single frame, because the adjusted thing to maintain sync is audio track, not the video track as usually. (normal vdub drops frames to maintain sync)

The problem lies in slightly different audio and video clocks in hardware. If there were a somekind of "sync-clok-singal" cable from video chip to audio chip, there would be no av-desync. But I think that there never will be such an option. (in TV tuner cards there is internal 'on-card' audio chip, but there seems to be problem wih them too) I use just my motherboard audio input to record audio. I noticed almost no difference in terms of audio clock accuracy, when I compared the onboard sound to SB live 5.1.

Only way to maintain av-sync is to do the routines in software (drop frames or adjust audio samplerate) or use hardware, that has audio and video chips in sync (singnal-clock-locked). For example the DV-capture cards (I don't remember what) usually, maybe always has that kind of locking. Maybe future capture cards just like 'bt-chipt' type cards now, will have those 'professional' type locks and good chips to maintain sync.

[^^-+I4004+-^^]

the interesting thing is that lip sync issues are not wdm only problem...
i'm currently working on(not mine,i'll try to fix it for somebody) a win98 system that has sync issues with original hauppauge drivers and not with the universal bt8x8 vfw driver
(but the latter makes intermittant chroma loss issues...)
(it's hauppauge(bt848) capture card/SB live combination)

this behaviour would suggest that hauppauge driver introduces some video frame rate drift and offcourse soundcard is not precise too (that's normal),so VDUb has no reference what to do,and there's massive loss of sync even after 5' of capturing.....

on the other hand,universal vfw driver produces stable video framerate (this is 25 for pal and 29,97 for ntsc...derived from the video signal sync portions) and soundcard still fluctuates a bit,but can be compensated with frame drops (or audio mod by VDSync)

**normal VDub takes audio as a reference (and modifies the video frame rate by the means of framedrops),and VDSync takes the video as a reference and modifies the audio (sligth sampling rate drifts)**
[the latter system is more eye-pleasing,and the first is more ear-pleasing (hehe...although this small sampling rate drifts are hard to spot....i couldn't differentiate these two for sure)]

needless to say,VDSync doesn't help at all with such problem...(because how will audio be corrected to fit video if video fluctuates too....)

so the answer why wdm has more problems is occuring (perhaps):
let's say that audio stuff stays as in vfw (soundcard has small drift)
and let's say that capture card driver exhibits the same problems as above mentioned hauppauge old vfw driver (video framerate drift)
[{ i think we should therefore attribute sync problems to capture cards drivers as in my case i have tried many wdm capture utils just to end up with same results.....now i have newer btwincap which seems to work better.....this is also mentioned in btwincap changelog etc.
hauppauge VFW driver issue speaks for itself too... }]
in this case we have lipsync problems.......
and WDM is relatively new system,so driver mfr's are still struggling (or better to say,extinct devices such as bt8x8 have less support now) as it seems.......vfw is all worked out long time ago....

also,i believe avery lee has a reason why he doesn't like wdm so won't make vudb wdm ready.......(perhaps the reason is lack of time,but perhaps not...)

but,the users without any problems on wdm (and there are lot of such users too) prove that drivers CAN be written in a way that keeps both WDM and lipsync satisfied......
the only issue is that bt8x8 has only one decent WDM driver (btwincap) and no one will develop another.(as bt8x8 goes out of fashion)
(although i don't even know if i tried other bt wdm drivers (iuLAB's and the factory one...)....and i won't......remember my FAT32 and WDM prog's segmentation issue.(even perfect lipsync won't do me segmentation fo bigger files)...but i do sometimes use WDM to capture shorter clips....WDM is (if nothing) much more CPU efficient)


[note how McQuaid is yet another bt8x8 user which struggles to make bt work ok under wdm........without a decent driver he won't succeed...]

see if these suggestions satisfy you.........



[>ivo and his computer...
800*600 and FAT32...

yes,hehe
tv-out solves the first issue(of 15" monitor),and VDub the second... i'm too lazy to install every program to win2k,so i just use win32 programs from my existing (and well backed up..hehe) win98 partition on win2k....therefore the need for FAT32...some folks even say that it's more efficient for video files (overhead,CPU load?) but i would probably use NTFS only if i bought my PC yesterday....but i didn't ]

/ivo

[Ookami]

@McQuaid

I would guess it's the implementation not the tech.

[Owen]

I struggled with sync for years on older hardware with Win 98, Win2k, Win XP.
Since I got an ASUS P4PE main board with ADI on board sound that, I think uses the system clock for referance. I have no more problems.

So my current setup is a P4 3Gig,(the 2Gig worked fine as well).
ASUS P4PE main board.
Win XP.
NTFS
MSI TV@anywhere WDM capture card.
FlyDS capture software. Capturing PAL 768-576 from Svideo input, direct to Xvid or DIVX or HUFYUV or Morgan mjpeg Version 3.x.

I have captured over 6 hours non stop with perfect audio sync and near perfect picture.
Works every time without issue.
WDM with this hardware works better than anything I have ever used over the past 8 years.
The only other thing that worked anywhere near this well was a Miro DC30 with its own on board sound.

Win XP is a great video capture and editing platform.
It's SOOOO RELIABLE. I dont know how anyone can stand the constant problems, crashs, restarts etc, with Win 9x.

Regards,

Owen

[McQuaid]

Well, back to my original question, capturing with your wdm apps, does it say 29.97 in both fields? You might say it's not significant (maybe just header info?), but from an older article I read about a/v sync it lead me to believe at the time that's it's important.

So I'm just curious on this.

Or maybe someone more knowledgeable on the subjet can explain what that field is actually reflecting in the avi or is just some header info thats easily corrected, but I think not.

[NeVeRLiFt]

AVI_IO and Virtualdub or the only software I have used that have never had or given me problems with audio sync.

I also like ShowShifter and iuVCR, but AVI_IO is my Favorite :D

[leoncheong]

Any of you here tried Virtual VCR? The author uses a different tech.
See here (http://www.digtv.ws/html/virtualvcr/sync.php)

[begu]

I think that virtual VCR and virtualdub sync uses same kind of resampling routines for audio to maintain av-sync. The main principle is the same.

I prefer the virtualdub sync, becsue it has real-time noise reduction while capturing. And it has cropping too, but as far as I remember, the virtual VCR had cropping too.

The differece is that virtual VCR uses WDM drivers, while virtualdub sync is using VFW drivers. I have only WDM drivers for my nvidia card, so the virtualdub sync is using the VFW WDM Wrapper. (I had the wrapper already there using winXP, so I didn't need to install it anyhow. And it is workin quite well, no big probs so far. The minor problem is the nvidia's wdm drivers, which sometimes cause field phase shif by one frame for the top field. (can be corrected with the field delay filter, as I earlier stated).

The results were the same using WDM with virtual VCR or VFW with the virtualdub sync (using wrapper). No difference in picture quality.

[fberreth]

I use virtualVCR which is cool.
It seems like when you use a WDM capture program that you have more CPU for processing compared with a VfW capture. That was important for me sine I have a slow machine (Athlon 900).

[Wam7]

Right, I have the same question as the subject heading but my query involves the quality of the video rather than the audio.

I capture from digital cable via s-video (composite) into a Hauppauge WinTV card with BT878 chip.I Use the WinXP with the Win2K VFW drivers (w2kdrv311.exe). I use VDub Sync or iuVCR to capture.

I did try the Hauppauge WDM drivers for the TV a while back but the quality was poor (blurring during motion) compared to the VFW drivers so I presume it would have been the same for capturing. The fact the VDub was designed for VFW made me stick with them.

Now I've heard about the BTWinCap WDM drivers and my questions is when it solely comes down to the quality of the captured video which is best? Or is there any differnce?

On an aside, my BT8x8 tweaker gives me an error when I try to activate it. Is this worth sorting out and implementing?

[fberreth]

Back to McQuaid's problem: I think the 29.97 is just header info, not really important. The real problem comes when you play back the stream. Either the PC or the video player needs to sync audio to video or video to audio since the playback (and also recording) clocks are never 100% accurate. So for instance, when you play back 44.1KHz audio it might get played back with 44055Hz. Over time there is a drift that is noticable, so that needs to be corrected.
VirtualVCR & Vdub with sync fix to SRC the audio to 48000Hz (for instance) but the same needs to be done for playback.

[Owen]

I don’t know how you got VFW drivers running on a Win2K of XP.
As far as I know they use WDM drivers ONLY.
VFW capture applications work well on Win9x, but on 2k or XP VFW capture apps must use the WDM-VFW wrapper to capture from WDM drivers.
This is not a good option, as the conversion from WDM-VFW takes up CPU resources.
In most cases resolution is also limited to only half.

As for quality. There is no difference between WDM and VFW, other than the resolution limits mentioned above.
If you want to use 2k or XP you should use a WDM capture application.

Regards,

Owen

[maxwell3]

Ive been following this thread with great interest as ,Im sure, have many others . I was wondering if some one could list which capture applications are vfw and which are wdm

[Wam7]

@Owen
Just in case you don't believe you can use VFW drivers in WinXP I've included a few links. ;)

http://www.wam777.pwp.blueyonder.co.uk/VFWXP.png
http://www.wam777.pwp.blueyonder.co.uk/sys.png

and a link to the driver if you want to try it. It's an old driver but it does what it's supposed to.
VFW drivers for 2K/XP (http://hauppauge.lightpath.net/software/wintvnt/w2kdrv311.exe)

You might be right about the quality during capture but for me the only way to get the WDM drivers as good as the VFW is to use DScaler when using them for TV viewing.

I did manage to sort out my BT8x8 tweaker problem out but the jury is still out as to whether it's worth using or not.

[bofw3]

Originally posted by Wam7
You might be right about the quality during capture but for me the only way to get the WDM drivers as good as the VFW is to use DScaler when using them for TV viewing.

AFAIK DScaler uses its own drivers, or better DScaler talks to BT8x8 directly, it won't use the SO's installed drivers.

[Wam7]

Yes I know, I was refering to the fact the Dscaler uses WDM. The Hauppauge drivers do or did have a cut down version of Dscaler routine built in but this was no way as good as the product itself.

[magnetoskop]

Yes I know, I was refering to the fact the Dscaler uses WDM.

then,how come ds also works on win98?
(win98se is the first wdm capable OS)
and as bofw3 said,ds talks directly to the hardware so (thanks to almighty) it doesn't need the drivers OR wdm (or vfw) at all....

(as in other programs first the driver talks to the hardware etc.)

but ds has great disadvantage:it can't capture.......

btw. nice to see confirmation that newer OS' work with VFW (probably because winNT had support for vfw so it stayed...)...

[Wam7]

My first introduction to DScaler was through Hauppauge, as it mentioned that using it could improve the quality of the WDM driver. I give way to yours (& bofw3) greater knowledge as it's been a while since I tried it.

Perhaps it should be mentioned in the FAQ that VFW can be used in Win2K/XP rather than having to go the WDM route and then using a wrapper if you want to use VDub.

[maxwell3]

Let me try again . Anyone have a list of which programs are vfw and which are wdm or know where I can get one ?

[Owen]

Warm7,
Thanks for the driver info but it's only for BT8x8 cards, is it not?
No much use for new conexant chip on MSI TV@nywhere.
I'm not aware of any VFW drivers for this card.
I doubt that any new products will be released with VFW drivers that work on XP.

Anyway, WDM works so much better for me then VFW ever did. I never want to use VFW again.

For me, VFW is dead. May it rest in peace.
Why do people still want to use this old stuff.
Have you all got old slow hardware?

I can capture to unlimited file size with perfect sound sync.
Could never do that with VFW.

If you have problems with WDM it is your hardware or drivers at fault. Not the WDM system or apps.

Warm7,
Your a good example. Why do use still use VFW with your hardware? WDM should work very well for you.
Use the freeware WDM BT8x8 drivers from :

http://btwincap.sourceforge.net/

They are the best.

maxwell3,
A list of some WDM capture apps.
FLYDS, VirtualVCR, iuVCR,

VFW capture apps.
Virtual Dub, AVIO and more I can't remember.

Regards,

Owen

[maxwell3]

Thank you owen and to everyone I learned quite a bit I wonder If anyone has ever put a list together . Ive searched but so far no luck

[begu]

Well, for that WDM-VFW wrapper thing:
I use GF4 and nvidia's WDM drivers for that card. It has philips TV decoder chip, and I believe there is no VFW drivers for it.

The Vdub sync works best for me (it uses the wrapper). I tried the Virtual VCR, and it was somewhat good (using the resampler). But I found the Vdub sync to be the best, not a single dropped frame never (and I've captured over 2 hours continiously).

I can use full resolution with the wrapper. Maybe the wrapper works good with the nvidia WDM drivers. However there is small problem with the field phase (sometimes I have to correct the field phase using the filter called 'field delay' and use 'delay bottom field' option.

But maybe someday I'll buy separate BT-chip based card and use the btwincap drivers and virtualVCR. But maybe I have to buy a real soundcard too (using onboard now) to get rid off quite big samplerate frequency drift. I think that the onboard sound-chip causes the variation in samplerate, so I have to use Vdub sync. But I'm happy with my current setup, because the video quality is quite good.

[Wam7]

Your a good example. Why do use still use VFW with your hardware? WDM should work very well for you. Simply because they've worked better than anything I tried. Just to expound;

I use my PC to watch TV and therefore need something that works efficiently and gives me a good picture. I tried the BTWincap drivers sometime ago and found them fiddly to get working at the time (probably just my experience) and also I had to use DScaler as TV program as the Hauppauge TV app doesn't work with them. Now, I'm not a fan of the Hauppauge TV app and DScaler can make the picture look really good (also works brilliantly with the VFW drivers!) but it uses too many CPU cycles and there are times when I can't give it the juice it needs to play smoothly as I sometimes encode in the background while watching the TV. So I can't rely on just DScaler for my TV viewing.

I capture with Virtual Dub sync (without need for a wrapper) using VBLE or Morgan Mjpeg at full res (768x576) for hours, 30+ gig files with not one dropped frame, even using my PIII. The quality of my encodes is very good so I'm only going to change driver if there is a marked improvement. Owen initially stated they (WDM & VFW) are the same quality, so on the face of it there is no need for me to want to change.

If anybody has a Hauppauge WinTV PCI card, they should try the VFW drivers as I know the quality for TV viewing using the Hauppauge TV app is definitely better. When I get some time I'll try the BTwincap drivers again for video capture and report back.

[jeffoz1]

I have been using the Hauppaugge vfw drivers that came with the card and vdub for quite a while with great flexibility and results. However I am now wanting to do scheduled recordings and need to change channels within the capture program and I understand that it cannot be done with vfw. Has anyone been able to do this or is WDM the only way with or without wrapper depending on the prog?
Thanks
jeffoz1

[tiki4]

Now I have to give my unwanted comments as well.

I own a WinTV PCI FM card for quite a while now and this card has given numerous troubles on my system. I'm still not too sure what the problem is, but it kept crashing all over the place (AthlonXP processor on VIA KT266A, sigh).

On-topic:

I tried in the last years all available drivers on my system under different Windows versions and the results were often near to nasty.

The VfW driver from Hauppauge works under Windows 2000 and Windows XP without problems. Windows NT 4 and its successors had and have a 32-bit implementation of the VfW driver model. Downside is, it is quite slow. If you compare capturing on Win98 and Win2K with VfW drivers the CPU load on 2K is much higher. Also you can't resize the TV signal to full screen with the WinTV2K app in NT, 2K, XP. You have to let it switch the screen resolution or you live with the black border.

VfW drivers on Win98 were significantly better, but kept crashing my machine like the NT drivers did. Both are no longer developed it seems as the lastest updates only appeared for the WDM drivers.

Hauppauges WDM drivers weren't any better for me. The only half to stable driver is the WHQL WDM driver for Windows XP (I use that for watching TV). Capturing is impossible with VirtualDub(Sync) at full resolution (strange error message). VirtualVCR works but crashes my machine when I close the window after capturing.

BtWinCap drivers are very good, and I use them now on an additional Windows 2000 on my hard disk solely for capturing. I use VirtualDubVCR (with the Sync patch) to capture at full PAL. I tried VirtualVCR in Windows 2000 and it seemed just to capture one field, which isn't what I'm looking for (seems like it captures 768x288 and resizes it then to 768x576, not good). I haven't sorted that out yet.

@jeffoz1:

VirtualDubVCR has an option to switch the channels, but it only works in Windows 98/SE/ME I'm afraid...
You might take a look at VirtualVCR with WDM drivers as this one can automatically capture from a given channel via Windows Task Scheduler.

tiki4

[leoncheong]

I have been using Virtual VCR as am quite happy with it.

Originally posted by tiki4
VirtualVCR works but crashes my machine when I close the window after capturing.

Could you elaborate on the crash issue, ,may be i can help..


I tried VirtualVCR in Windows 2000 and it seemed just to capture one field, which isn't what I'm looking for (seems like it captures 768x288 and resizes it then to 768x576, not good). I haven't sorted that out yet.


How did you verify that? What codec are you using? Can you card driver capture both filed in the first place?

[tiki4]

@leoncheong:

The crashing of my machine is due to the Hauppauge WDM drivers. I never got any driver that worked stable on my machine (Athlon XP 1600+, VIA KT 266A, Audigy, Hauppauge WinTV PCI FM). It also crashed often when I switch the driver from DIBDraw to Overlay. The OS and driver version doesn't matter that much. The VfW drivers for Windows NT/2K and Windows 9x crash my system even worse.

The only stable driver I found so far is the btwincap one.

Now please don't tell me to swap PCI slots or disable ACPI, that doesn't help, I tried everything. I've been discussing that topic quite a long time ago in that forum but noone found a solution so far. I just got some statements from the WWW that Hauppauge is developing on Intel boards with Intel processors and nothing else, I don't think that changed.

VirtualVCR seems to capture one field with the Hauppauge WDM driver. I just can't see any interlacing in the final AVI file. Anyway that is a minor problem as it crashed the computer when closing the window. The wrapper and VirtualDub don't work either as everything above 288 lines gives an error. I think Hauppauge could considerably improve their drivers. Ah, the codec I used was PICvideo MJPEG /w quality 19 and 'capture 2 fields above 288 lines'.

Puh, that is too long now, sorry.

Cheers,
tiki4

[maxwell3]

[tiki4]

What's up, maxwell3? No fun in posting anymore?

tiki4

[maxwell3]

I started to post and realized I had nothing of value to say . Im still in my video captureing infancy and at times it gets a little overwhelming. Its kind of like going to college to learn about a subject and getting the information from all 4years in an unustructured , haphazard way . Thats not to say I dont value that information . I greatly appreciate all the posts here and in other threads . I just have to set it all aside from time to time to absorb and sort thru all Ive learned and to try to fill in the gaps in my understanding.

[tiki4]

After 2 years of capturing I saw recently that sometimes no filtering of my captured files at all provides much better quality than my previous filter chains...

We're all just here to learn. :)

tiki4