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Old 28-04-2010, 10:13 PM
Andrew C
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Andrew C is offline
 
Join Date: Oct 2007
Location: Adelaide
Posts: 85
Hi Jonathan,

When I tried a couple of weeks ago now to set virtualdub to less than 25fps in file>capture AVI>capture> settings, it would not accept the change, always reverting to 25fps.

I asked questions on the web, and was advised that some capture devices (ie. the hardware plus driver software) could be set to operate at less than full framerate, and some (such as mine presumably) could not.

Are you absolutely certain that all capture devices and their driver software can only output at the full frame capture rate? If so, maybe GStar-capture will do what I want. I fully understand that PAL cameras themselves output at 25fps, but the evidence seemed to suggest that the problem was in virtualdub not being able to control the capture device in my case. I was able to work around this to a degree by limiting the capture time to 1 second and the capture file size to a couple of MB in virtualdub, but that meant a lot of manual work joining AVIs, which was a pain.

I will give the easycap/GStar-capture combo a try before abandoning easycap altogether, but I would be interested to hear further from you on this. My understanding is that the capture device is an A to D converter, so the output from it is no longer an analog PAL video stream but a set of digital AVI frames.

On the question of redundant/same frames not harming the stacking process, I agree with you; it is just the enormous multiplier effect on the number of frames that would have to be stacked to get the same effect: to stack say 100 'distinct' frames at 128X integration (derived from 100 x 2.56 second streams) would require 6400 'mixed' frames which would therefore take 64 times as long to process.

Andrew
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