Can't capture without dropping frames...

[peskypescado]

I have a WinTV PCI with the BT878 chipset. It works fine for just watching TV with a variety of programs, but I can't capture without dropping frames. I'm sure my PC is fast enough (nForce 2 AMD 2600+, 512 DualDDR, 7200 rpm 80gb Maxtor). I'm running WDM drivers and have tried to get a variety of different WDM drivers to work but I have found for my hardware that the updated Hauppauge WDM drivers work best. Anyway, I drop about 1 out of 30 frames @ 29.97fps, or like 5 out of 15 for 15fps. It's terrible. I've tried VirtualDub, MyTV, FlyDS, and about 8 other programs and nothing works. Can someone tell me something I'm missing? I've also tried it with Divx 5 (VBR 350kbit-2000kbit), and HuffYUV.

Thanks,
peskypescado

[SundanceKid]

At what resolution are you capturing?
I have the same problem when capturing with higher resolutions than 352 x 288.

cheers

[Malow]

###- check if your board are sharing irq (works, but is better no)
###- chage bios settings (reaaaaallyyyyy strange... some settings give better cpu usage, no frame drops, and others green lines in video)
###- if using virtualdub and more than XXXx288, use ddraw acceleration in both fields , if a Dshow capture app, use smart tee
###- change card slot (in some slots strange things can happens)
###- btwincap drivers is the best but not more stable for me (i have a pixelview with bt878a)
###- use YUY2 color space
###- u capture in pal or ntsc? formats have different framerate
###- crazy things can help too (bt878 is a good enteirtainment..)
###- the mainconcept dv codec can help (median hd and cpu usage, good for test, different from huffyuv (high hd) and divx (high cpu)

tell more about your capture settings (frame size, frate, colorspace)

Malow

[peskypescado]

Originally posted by Malow
###- check if your board are sharing irq (works, but is better no)
###- chage bios settings (reaaaaallyyyyy strange... some settings give better cpu usage, no frame drops, and others green lines in video)
###- if using virtualdub and more than XXXx288, use ddraw acceleration in both fields , if a Dshow capture app, use smart tee
###- change card slot (in some slots strange things can happens)
###- btwincap drivers is the best but not more stable for me (i have a pixelview with bt878a)
###- use YUY2 color space
###- u capture in pal or ntsc? formats have different framerate
###- crazy things can help too (bt878 is a good enteirtainment..)
###- the mainconcept dv codec can help (median hd and cpu usage, good for test, different from huffyuv (high hd) and divx (high cpu)

tell more about your capture settings (frame size, frate, colorspace)

Malow

I tried various frames sizes, rates, and colorspaces. I was trying to get 320x240 to work primarily though at 29.97 fps. But I tried 15 fps too and 352x240, 640x480,. I tried RGB 24bit, 15bit, UYVY, YV12, YUY2, and a couple others I think too. My cpu is fast enough that divx wasn't bogging it down, especially at 320x240. I even tried puting the quality to medium to lower the processor load. It was only at like 20% when capturing, and I did pcm and mp3 for audio too. The btwincap drivers don't work well for me in cap programs. It always installs setup for PAL and I use ntsc. I couldn't figure out how to change this even though it says that it can do either. I had ddraw enabled for both fields. My card is on IRQ 19 which my GF4 Ti4200 uses, but I can't change either of them. I haven't tried a different slot yet. I might try that. I did install the VFW drivers that are for my WinTV card from Hauppauge and they work fine in VirtualDub. No sync problems, but a lot of programs want WDM. Also with the WDM drivers it will scale the picture past 100% in programs which the VFW won't do. If anyone can tell me how to get the btwincap drivers to do ntsc I'd try messing with this again. I've install and reinstalled me drivers like honestly 50 times trying to get this to work different.

Thanks for the suggestions,
Pesky

[jdevers]

I have the exact same problem...mine is arguably more interesting though.

I have a similiar system, Athlon 2400+ running on an Nforce 2 board with 512 MB RAM with Windows XP.

I can capture in VirtualDub fine except for I loose about 1 in 30 frames. Every so often though, this problem takes a different road, I drop the normal number of frames for the first 10,000 or so frames and then the drops seem to lower to a much more acceptable level, like 1 in 500 frames or so. This doesn't always happen, but does occasionally. Now even MORE rarely, I am able to load up Vdub and capture for an hour or more without loosing a single frame.

This would lead you to believe that a program running in the background is contributing to this, but I have killed EVERYTHING non-essential before and it will drop 1 in 30 then sometimes I want to just check a new filter out and cap a few hundred frames and it will catch every single one all with my normal workload running in the background.

I have tried every respected capture program, both WDM and VfW, and get approximately the same results. I use the btwincap drivers and have experimented with different VfW wrappers etc, all to no avail.

I honestly have no idea what is going on, I've tried every resolution, frame rate, and color format that are feasible. I've tried capturing without audio at all, with audio in numerous formats and codecs, with the video uncompressed, HUFFYUVed, MJPEGed, and (gasp) XVID realtime...all with the same results.

I have a PCTV bt848 card and am using the onboard nForce audio (not the problem as the exact same results occur both when using an SB Live and when no audio is captured). It isn't the drive as I have a completely empty 40 gig drive that I use for nothing but video processing and I have used it in the past with stellar results and the exact same capture card (previous MB, CPU, and install of XP).
The board is on bs-IRQ 16 without anything else.

Any ideas?

[Jeff D]

Malow, what's "smart tee"?

peskypescado,
I was having a hellof a time getting captures to work, different setup though. Mine was ATI AIW 8500.

The IRQ sharing... I was able to stop that by disabling some hardware components (USB and other, just while I was getting this all trouble shot) Try moving the card to a new slot. Try slot 2, most mother boards have slot two configured to not share IRQ (is that right?)

One suggestion by bb was to use the VirtualdubVCR mod, which works better with the AV sync differences that can cause dropped frames.

Other things to check...
benchmark your drive with a LARGE file, vdub config app has a benchmark button, use that.

The real question is what part is responsible. The benchmark of the drive (you should really try a second tool that will give you longer test times, sorry I don't know of any) get the write speed, my drive was about 50MB/sec. Check your cap bitrates and see how those compare to the drive write rate. You'll at least know if the disk write is the problem.

Try different disk i/o settings, for me 6MB 4 buffers worked best (odd, but it worked), disable the windows buffering.

Also, have you tried cap without audio?

I was cap my SW laserdiscs, to move to DVD. I don't want ANY dropped frames for fear it would screw up the IVTC converting back to 24fps...

Good luck.

[Malow]

Jeff D,

iuvcr help:

"Use Smart Tee for Preview" Some video capture cards (bt848/878) do not provide simultaneous recording and preview if frame size exceeds 288 vertical lines in PAL/SECAM or 240 lines in NTSC due to hardware and drivers revision. You may enable the "Use Smart Tee for Preview" option to override these restrictions. Then the video stream is split by a special "Smart Tee" filter, which is emulated by the CPU. It does not depend on the Preview function realization in the video capture device. It provides simultaneous recording and preview processing independent of the captured picture size. This option isn't used with the cards with Preview function hardware support (ATI, ASUS, etc). Important: enabling this function may result in some additional video streams mistiming!

Malow

[dar1us]

Originally posted by jdevers
I have the exact same problem...mine is arguably more interesting though.

Hehe, sounds sooo pompus:) Nice and English like:D

Everyone, have you all read through the pages upon pages about this, there must be a good 20-25 threads in the past half year (all very relavent) on frame drops. Thanks to Malow for summising solutions. Did they work at all?

Still, look at other threads, a recently active ones are http://forum.doom9.org/showthread.php?s=&threadid=47741
Theres another, but I cant find it, I swear there was something like 30 posts on it, may be in another thread, topic migration.


dar1us

[Jeff D]

I'm going to kinda move from the topic....

I've been looking at the data vdub spits out during while capturing from my AIW 8500. I've noticed the capture average frame constantly drops, displayed now is 29.96562 and dropping, the fact that it's dropping has me concerned. I would figure it would level out at some point as the frame count grows larger, no?

VT adjust was sitting at -6ms for the the first 5-6 minutes, then is worked it way back to 0ms over about half a minute's time. Progressing +1ms each 5-10 seconds. After reaching 0 it jumped quickly up to +34ms. This too seems odd to me.

I don't understand the internal mechanics, nor how reliable these numbers are calculated. Are these numbers reliable?