http://www.shspvr.com/forum/viewtopic.php?t=6403

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-Dano

Hi Dano,

But wouldn't this cause more CPU burden
Because I see no difference in doing this, than with a BT878 card
The idea of capturing MPEG-2 at the hardware level, is because the on-board CPU is doing the compression.
If you capture to AVI (HuffYUV, MJPEG), you're using the computer's software Codecs, so there's a lot of overhead in the computer's CPU

-kwag

If you are using something like Huffy or PicVideo MJPEG then a fast hard drive is all you need with a half decent computer. As a matter of fact cpu usage is around the same with VVcr as it is with WinTV2k. I have been using a PVR-250 and now a PVR-150 to capture at 12000-15000 Mbs and then reencoding via AVISynth with remarkable results. The real secret behind the Hauppauge cards is their DNR filters which if used moderately (unfortunately the defaults are far from moderate) can help produce a really nice looking capture going into AVISynth. I agree that if you capture at DVD bitrates and your source is VERY clean (many of my stations have a lot of noise-analog cable) then the hardware mpeg is outstanding. To wrap it up, the PVR-150 filters used on an AVI source are noticeably better not to mention the ease of editing in VDub (no more DVD2AVI, just trim commands).

__________________
-Dano

Now that's a BIG advantage
But don't you get dropped frames, capturing 720x480 with HuffYUV
Unless you have a very fast computer, and a very fast drive, you will loose frames, even with the PVR-150

-kwag

I used to capture 720x576 with HuffYUV on my 900MHz Duron and a UDMA-33 5400rpm hard drive. No dropped frames whatsoever

I guess I've always had kind of trash hardware :P
But you're right, the key ingredient is a fast IO channel to the drive. SCSI is even better

-kwag

And if you happen to have a HD only for the captures, even better. Or at least use a different HD than the one with the OS and swap file on it.

Yep. For sure
However, one thing where I can guarantee frame loss, when capturing to AVI via HuffYUV, with no matter what hardware, is that if you start messing with the machine like browsing and opening applications, you WILL get dropped frames.
That's one of the beauties of the WinTV PVR 250, capturing to MPEG-2, where you can do just about anything you want with the machine, and there are zero frames dropped, even at 720x480.
I tried this last year with a P4 @1.8Ghz (fast enough), and a 10,000 RPM Seagate Cheetah SCSI drive, using a WIDE SCSI Adaptec controler. There were dropped frames once we started messing with the machine.
At 352x480, there were no dropped frames, even when using the machine heavily, but it was impossible not to drop frames at 720x480.

-kwag

I purposely stressed the card today just for this reason. I am capping at MJPEG 19 Quality. My specs that matters are P4 2.4 HT, OS drive WDC 37G SATA 10k, capture drive Maxtor 250G ATA133, 512Mb PC2100. I checked this on a currently recording scheduled capture using vvcr scheduler with "Use /High switch to start VirtualVCR" in vvcr scheduler options (don't know if this helps or not). To stress the card I started an encode using CCE, opened IE and then Outlook Express. Only one "dropped2" frame so far (after 58 minutes) and CCE is still running. I would not be able to do this on a BT card, especially if filtering while capturing (ffdshow raw video helper). I don't know if it matters but I have selected VMR in Hauppauge "Primary". I am pretty surprised by this myself since I think what VVcr is doing is uncompressing the HCW2 stream.

__________________
-Dano

It would be good to make a test with a BT card, because in theory, there's no difference, because both cards are simply grabbing video and sending it to the Windows driver. So in this mode of operation, the PVR-150 should perform identically to any BT8x8 card.

-kwag

As far as filtering goes I think there is a difference. I believe the filtering is done in hardware on the mpeg stream which is then uncompressed in Virtual Vcr. This is a big difference from directly filtering the avi stream in software alone. I have tried ffdshow filters using a BT card and not only were they not as good but I was unable to use the computer for anything else without dropped frames. If you do not use filtering on either type of card then there is no difference. The PVR-150 does have some nice features though for $99: builtin IRBlaster, dual 10 bit DAC and 4:2:2 YUV.

__________________
-Dano

Now that's a difference
Most BTx cards are 8 bits, so that's definitely a huge difference in quality

-kwag