Dropped frames

[mario64]

I need some assistance with a dropped frames issue. I've read the faq's posted here and made those changes yet I continue to get a small number of dropped frames - around 16-20 in a 2 1/2 hour movie off of Laserdisc. Bad thing is they always occur together, say 6-8 at a time, so they are often noticable.

This is only when capturing AVI files though. I can use MMC to capture DVD Quality MPEG2 all day long without any dropped frames at all. I've tried MMC, VirtualDub, Virtual VCR and iuVCR in combination with HuffYUV and PicVideo MJPEG. No matter which combination I use I get dropped frames.

Here are my system specs:
P4 3.4GHz
1 GB RAM
SB Audigy 2 w/latest drivers
Radeon X800XT PE w/official CAT 4.12 and MMC 9.03
Xp Pro
Dedicated, brand new, WD 250GB hard drive w/8 MB cache

Shouldn't this system be able to capture AVI with no dropped frames at all? Am I expecting too much?

Thanks,
Mario64

[lechtin]

I do some AVI capturing from a ATI TV Wonder with Virtual VCR, PICVideo MJPEG (quality 19), on a PIV 1.6GHz with 1.5GB RAM and do not get any dropped frames. Your system is so much more powerful than mine, it should not cause you any problems. The only thing that is not clear is your HDD setup. Make sure your capture drive is not the same as your system drive (I mean drive, not partition) . Also, you might want to put them on separate channels and disconnect the DVD/DC drive(s) just to experiment so that all you have is a Windows drive on primary master and capture drive on secondary master. Do you have a lot of active programs (antivirus, desktop managers, spyware, ...) Keep these to a minimum.

When you capture from the laserdisc, do the dropped frames always occur at the same scene or frames? Maybe it's the source material that is just too complex. Try playing with the capture settings (bitrate, resolution) and see if that makes a difference.

[mario64]

I do some AVI capturing from a ATI TV Wonder with Virtual VCR, PICVideo MJPEG (quality 19), on a PIV 1.6GHz with 1.5GB RAM and do not get any dropped frames. Your system is so much more powerful than mine, it should not cause you any problems. The only thing that is not clear is your HDD setup. Make sure your capture drive is not the same as your system drive (I mean drive, not partition) . Also, you might want to put them on separate channels and disconnect the DVD/DC drive(s) just to experiment so that all you have is a Windows drive on primary master and capture drive on secondary master. Do you have a lot of active programs (antivirus, desktop managers, spyware, ...) Keep these to a minimum.

When you capture from the laserdisc, do the dropped frames always occur at the same scene or frames? Maybe it's the source material that is just too complex. Try playing with the capture settings (bitrate, resolution) and see if that makes a difference.

Thanks for the reply. My capture drive is not my primary drive or a partition. It is, however, a slave drive on the same channel as my primary drive.

I kill off everything running in the system tray and those I feel safe killing in Task Manager. NAV is disabled but not shut down.

I know for sure HuffYUV drops frames at different places than MJPEG but I haven't compared the different capture programs to see if it's related to which one I'm using.

Mario64

[Nelson37]

Get the capture drive onto a seperate channel from the primary OS drive.
This is plastered all over the FAQ and practically every post on the subject.

[travismoran]

@mario64:

I don't know if this will help, but I noticed it wasn't mentioned:

After I defrag my capture drive I don't get any dropped frames.

I use a dedicated 80Gb WD drive for capturing with separate channel and all the specs mentioned in previous posts, but I don't always process all my caps immediately. Every now and then I used to get minor frame dropping. I use IUVCR with PICVideo MJPEG mostly, but all other cap progs/codecs did it too.

I learned to defrag very often and don't have the problem any more. My system is not nearly as good as yours and I get 0 drops now.

[dj4monie]

I agree -

You should keep your PC in good running condition to prevent dropped frames and other issues that can pop up anyway.

I've captured several things and only dropped frames once when I captured something off Direct TV. I wasn't even here and it dropped 2 frames total and that's with everything I normally have running in the system tray and using my main 60GB drive for captures.

That has been so far my longest capture and that might have something to do with it, but I have a P4 2.4Ghz, with 60GB and 10GB drives and ATI AIW 9600XT. I have the latest complete drivers (4.12) and MMC 9.0 and I capture mostly to WMV for portable devices.

[mario64]

Thanks to everyone for their replies. I do defrag often and unfortunately still drop a few frames when capturing on a newly defragged drive. I guess it's either my source material or the fact that my capture drive is on the same channel as my primary drive. Problem is I can't change that due to physicial limitations inside my computer case.

I did find out the other day that I seem to be able to capture MJPEG using MMC 9.03 with no dropped frames but cannot with HuffYUV for some reason no matter what capture program I use. I actually preferred ATI's direct MPEG2 capture though (and it's much faster) so I've settled on that method rather than AVI captures converted to MPEG2.

Mario64

[non-linear]

I'm wondering if your primary drive is dragging down your capture drive. I have both my hard drives on the same IDE channel, and the only time I drop frames is when I have bad sources.

Do you have DMA enabled on both drives? What speed is your primary drive (RPM)?

The rest of your system specs sound fine. I can't see it being a processing issue, as it takes more processing power to capture MPEG2 than it does for AVI (from my understanding). The only thing I can see it being is related to the hard drive, if it can't write the data required for AVI, as AVI typically requires more data compared to MPEG2, so the drive probably can't keep up with the demand.

You could try moving the drive to the secondary channel, or just go with capturing in MPEG2, using a high bitrate (8Mbps or more). If it's the primary hard drive that's interfering with it, depending on how old and slow (if it's 5400RPM) it is, you may want to replace it with a newer one. But I'd suggest you check your DMA settings first.

[mario64]

Thanks non-linear. I've confirmed that both drives are in Ultra DMA mode 5. Both are 7200 RPM drives but from different manufacturers. Primary is a 160GB Maxtor, secondary capture drive is a 250 GB Western Digital. Both are NTFS.

Maybe it is just a source issue. Are AVIs more sensitive to that? The drops do always occur together (6-8 at a time).

Or maybe there are more Windows services that I need to shut down. I disable everything I feel safe disabling, including NAV.

I don't know.....

Mario64

[Nelson37]

It is not a source issue. Very simple. An uncompressed or Huffy AVI constitutes the largest file, and highest sustained data rate, which results in MAXIMUM throughput to your drive. Two-tenths of a second of interference would result in 6-8 dropped frames. MJPEG works because it results in a smaller file. Very minor changes in VDUB buffer settings, or using the "software RAID" for audio, could make the difference.

However it is very likely that your drops are caused by periodic OS writes to the primary drive, which takes the IO bandwidth from your capture drive as it is on the same channel.

Any time you mix two non-identical IDE drives on the same channel it is possible to suffer a performance loss, sometimes dramatic. Drive performance will NEVER improve from such a mix.

[mario64]

Interesting info. Thanks very much. Which specifc VDUB buffer changes should I make?

Mario64

[mpack]

This may or may not help:-

You don't mention what format you use for audio capture. The natural choice if you are going for high quality (which is presumably why you use Huffyuv for the video) is to use PCM for the audio. But, I have found that I get far fewer dropped frames if I let MMC use its MPEG audio encoder for the audio cap, and I've not noticed any drop in audio quality because of it.