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Recording Sometimes Fails When Using Xvid Codec
When trying to record using the Xvid codec, sometimes I get the following error pop up:
The specified device handle is invalid. in Stop()
This is followed by the following error pop up:
CamStudio could not record the AVI file using the current compressor. Use default compressor?
Both error pop ups only occur if I have "Record Audio from microphone" selected (Options->Record audio from microphone). With either of the other two audio recording options selected, only the second pop up occurs.
Through trial and error I found the following:
1. If I used the "Region" method of selecting the area to record (Region->Region), the error(s) would pop up as soon as I finished selecting my region. But sometimes the error(s) would not occur. If I tried over and over to do my selection, eventually I could get it to work.
2. If I used the "Fixed Region..." method of selecting the area to record (Region->Fixed Region...), the error(s) would occur every time I pressed the Record button, but only if the error(s) occurred the first time for a particular configuration of the region. If the Record worked the first time for a particular configuration of the region, it always worked.
I found this problem described in various places on the Internet. In some places the suggested solution was to use even numbers for the width and the height of the record region whenever using the Xvid or similar codecs. I tried this but it did not help.
Eventually I figured out that when you configure a fixed region for the capture, the resulting width and height of the recorded video ends up being 1 pixel less in both width and height than what you configure. Further, I realized that if you specify both a capture width and height of odd numbers, the capture will always work. Presumably when you specify odd numbers, the actual values are reduced by 1, making each one even, which then matches the suggestion I had seen of using even numbers for the values.
I'm also assuming that when using the "Region" method of selecting the area to record (Region->Region), if an area with a width and height of odd numbers happened to be selected, the recording would work.
So the obvious solution to work around this problem until it's fixed is to always configure a "Fixed Region..." and to always use odd numbers for the width and height.