For original message look for ORIGINAL in text.

Ok, did some further investigations and it seems to be a driver issue or a VDub issue.

Capturing at any vertical resolution will produce massive framedrops if horizontal capture resolution is lower than 704.
Ex.: 352x288 massive drops
704x288 zero drops
480x576 massive drops
704x576 zero drops
400x300 massive drops
704x300 zero drops
Tried to change desktop resolution, bit-depth etc...same problem.
VDub and VDubSync both versions 1.4.10 same problem.
Tried lower VDub versions up to V1.4 same problem.
Tried different drivers: iulab's, pinnacle 4.02/5.01/5.10, btwincap
Tried different software: VDub/sync, AVI-IO, iuvcr, etc...
Tried newest NVidia/SBLive WDM-drivers

I desperately want to capture at 352x576 with zero frame drops as capturing at 720 or 704x576!

Any idea???

Regards,

Manuel.

ORIGINAL ORIGINAL ORIGINAL Below...

First my capture config:

Celeron II 566 @ 935Mhz
Asus CUSL Mobo (I815E)
Geforce2 MX
9GB 7200 RPM primary master boot drive
60GB 7200 RPM secondary master capture drive
2.5GB drive (not used for caps)
256MB PC133 CAS2 RAM
SB Live Value
Pinnacle PCTV Rave capture card

Used software:
Windows XP corporate edition (clean install)
VirtualDub and VirtualDubSync V1.4.10
latest BTWincap drivers for PCTV Rave card (sourceforge)
Compression type HUFFY
Encoding/filtering soft: VDub/Tmpgenc/Cinemacraft etc...

Capture source (PAL):
VHS 2nd and third generation recordings.

So here's the deal:
When doing captures at full D1 res (720*576 or 704*576) I get zero (0) dropped frames with preview mode active even for 2h caps.
YUY2 capture setting and huffy at best compression setting.
Processor load is hovering at about 60-80%.
Disk throughput about 7.5 MB/sec

When capturing at half D1 (360*576 or 352*576) it keeps on dropping frames gradually until it looses sync completely (dropping frames like hell is breaking loose and fps goes down from 25 to 12...)
Same problem for 480*576 or 640*576 but framedrop is less.
Also 352*288 gives lots of framedrops like half D1.

Sure you would say, go for full D1 if it gives no problems...
But, capping at full D1 uses a humongous amount of space and my final video settings are preferably 352*576 for future transfer to DVD. (now using SVCD)
Bicubic rescaling to 352*576 adds a significant amount of time (does only 9-12fps) so this method is not preferred.

Went thru the BT878 and 879 technical docs and it seems that the chip samples the horizontal lines at the same frequency independent from horizontal cap resolution and rescales it internally (on chip) to the desired horizontal resolution (set by the software).
So your horizontal cap resolution is not influencing the horizontal sync. (the capture chip doesn't get more signal to work with)

Someone has a fix for this or similar problems?
More config info needed???

Regards,

Manuel.