OpenCV how the frame is grabbed out from WebCam?

asked 2017-06-15 09:20:14 -0500

hongyuanlu gravatar image

updated 2017-06-15 13:05:34 -0500

LBerger gravatar image

I am wondering in a single frame grab

cap >> frame

If I am using Logitech C920 which has its own hardware encoder, and I am grabbing 720p image, Am I getting 1280 * 720 * 3=921600 * 3=2700000 bytes from the USB port directly?

Or I am getting a compressed image out first and decode it into 2700000bytes?

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idk about your logicam, but most webcams send compressed data over the wire (the usb bus is the bottleneck here)

yuv422 is a popular format here (3 color bytes compressed into one)

berak gravatar imageberak ( 2017-06-15 09:33:24 -0500 )edit