MPEG4 NETWORK IP CAMERA User’s Guide
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6.2 Image Configuration
Rate Control
Select the Rate control by selecting the VBR [Variable Bit Rate] or CBR [Constant Bit Rate] control.
In VBR mode, the picture quality is fixed with fixed quantization value and the bit rate varies
automatically in reaction to the complexity of video to maintain the set quality. Thus using the more
bandwidth for complex video and less bandwidth for lower activity video. VBR is appropriate for storage
applications. VBR can be used where video needs to be streamed over a fixed-bandwidth link.
In CBR Mode, the bit rate is fixed irrespective of image complexity, and the picture quality is
automatically adjusted by the MPEG4 encoder on a frame-by-frame basis to maintain the pre-set average
bit rate. Thus the network bandwidth consumption is always fixed & predictable. CBR is of particular
benefit where video needs to be streamed over a fixed-bandwidth link.
