Something is not adding up here. I think I found your card and here are the max framerate specs claimed by the manufacture:
Video Digitizing Formats and Maximum Frame Rates
Color format, Capture resolution, Frames per second, Notes:
RGB32 160x120 15 ...
RGB24 160x120 15 ...
RGB16 (565) 320x240 15 ...
RGB15 (555) 320x240 15 ...
Y8 320x240 30 Greyscale
RGB 8-bit dithered 320x240 30 ...
YUY2 4:2:2 320x240 24 UYVY by byte swapping
BtYUV 4:1:1 320x240 30 3 words pack 8 pixels
YCrCb 4:2:2 320x240 24 ...
YUV12 320x240 24 Verticle subsampled 4:2:2
YCrCb 4:1:1 320x240 15 ...
YUV9 320x240 30 Verticle subsampled 4:1:1
You indicated a resolution of 387x288. DivX must be blowing up a smaller original of 320 by 240 to get 387x288. This is a little wasteful and you might do even better by going to 320 by 240 since that is (evidently) your source size.
Does your card or software say anything about Zoltrix?? I'm gonna try divx4 tonight and see if I get results like yours. Using ATI's mpeg2 I can do 640 by 480 at 24 frames/ sec including sound with no dropped frames but using divx3.11 the best I can do is about 18 frames/sec at 320 by 240 with no sound.
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