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| Image Compression Technology and the Speed |
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Video Image Compression Technology is the core of web cameras because the compressed video file size should be small enough to run fast through a network line of the Internet or LAN. Another main factor to decide the speed of a web camera is the speed (bandwidth) of the network line itself. How to Compute the Speed a) " The speed of a network line " divided by 8 is numerator. Please note that 8 bits is 1 Byte. For example, if you use 192 Kbps DSL line, the numerator is 24 KBps (192 divided by 8) if you use 384 Kbps DSL line, the numerator is 48 KBps (384 divided by 8) if you use 1.1 Mbps DSL line, the numerator is 137 KBps (1,100 divided by 8)
b) " The size of the compressed file of a video picture " is denominator.
It depends on the format a web camera uses to compress the video picture.
For now, Wavelet is the best format for this function. Following table compares the Wavelet and other formats.
Now, if you send video pictures of 360 by 243 resolution over 384Kbps DSL line, the speed is ;
if you send a picture of 720 by 486 resolution over 1.1Mbps DSL line, the speed is ; < * Above speeds are maximum. Actual speed may be lower depending on the traffic and other conditions. > |
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