#1 Performance patch for streaming V4L1 drivers

[ThorstenB]

Hi Marco,

I have attached a patch for the V4L1 support of wxCam. It significantly improves the frame rate for drivers with V4L1 interface, when the driver/camera supports streaming (most cameras do). Using the gspca video driver and a Logitech Messenger webcam I could more than double my frame rate (rate is now limited by the camera spec).

For these drivers it is important to use all frame buffers (so far, wxCam was only making use of first frame buffer). The driver stores streamed images automatically in consecutive frame buffers (in a round-robin fashion 0,1,2,3,..,0,1,2,3). In order not to skip any images, wxCam must collect the image data of all frame buffers given by the driver to achive maximum frame rate.
The attached patch should be clean and straight forward. Hope you can commit this to CVS. Let me know, if there were any issues.
I'm not sure about V4L2 support - there may be a similar issue?

cheers,
Thorsten

[ThorstenB]

frame rate patch for streaming V4L1 drivers

[coldfusion]

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Thanks for your submission, I have seen it only today. Your work seem very interesting, I'll test it quickly... I think I'm already using this feature in v4l2 code.