60 is a CMOS sensor manufacturers OV first put forward, that is, under the VGA resolution , 60 frames per second display screen , but this large amount of data , so only in digital transmission format MJPEG run .
The current camera-free drive , there are two transmission formats , YUY2 and MJPG, YUY2 is uncompressed image format , MJPG is the equivalent JPEG image compression format to loss of image quality to reduce the data rate. And 60 frames / sec , in MJPG mode, there are plenty of light can be achieved. CMOS type with CCD , CMOS reducing the light , through the slow shutter speed to extend the exposure time , when down to 1 /30 sec , the frame image screen . If the CMOS unsupported draw , only through the "Frame Copy" to copy the frame adjacent filled into a data stream , as obtained with the interpolated pixel , the image is large, but only a blurred picture , the image resolution has not been fundamentally improved. Now, only the specifications OV7725 VGA book clearly stated under the 60 frames / sec , others are not seen .
120 pure bullshit , the first not to say that in the CIF (320X240) can be achieved , such a high frame rate , but increase CPU resources , and only changed the argument, according to the current bandwidth of USB2.0 , VGA next with MJPG compression format is unable to provide 120 frames / sec data transfer , so the screen can only be reduced by half . Or that the performance of DSP reach so strong. DSP on the use of the middle frame to copy from a frame filling vacancies in the data stream , so the light is low , CMOS camera will smear is like, but the exposure is better, and the same lens , CCD is darkening images to see the details unclear. Therefore , the camera DSP has a very important function - "Frame Copy" , the real camera 60 frames , requires CMOS support , only the CMOS sensor output is 60 frames , only the image information of 60 different
Fake hardware 120 and 60 , the direct use of DSP interpolated frames made out of , in fact, is not used to provide 60 effective CMOS image output , with the interpolation same reason.
Fake software 120 and 60 , the preparation of an AMCAP, before the number of the display frame rate and then multiplied by a numerical display, so 30X2 = 60,30 X8 = 240, soon , 240 cowhide blew out, that is not difficult, even data is not transmitted.
So for the USB camera , the 120 and 60 without any enhancement of the role of . Purely speculation.
