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Constant bitrate (CBR)

When referring to codecs, constant bit rate encoding means that the rate at which a codec's output data should be consumed is constant. CBR is useful for streaming multimedia content on limited capacity channels since it is the maximum bit rate that matters, not the average, so CBR would be used to take advantage of all of the capacity. CBR would not be the optimal choice for storage as it would not allocate enough data for complex sections (resulting in degraded quality) while wasting data on simple sections.

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What is WHQL?
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All Hanbang DVR cards pass WHQL.

Windows Hardware Quality Labs testing or WHQL Testing is Microsoft's testing process which involves running a series of tests on third-party (i.e. non-Microsoft) hardware or software, and then submitting the log files from these tests to Microsoft for review. The procedure may also include Microsoft running their own tests on a wide range of equipment, like different hardware and different Microsoft Windows editions.

New since June 2007 is the requirement of a Fidelity Test equipment (Audio Precision SYS-2722-A-M) for System Submissions.

Products that pass the WHQL tests get to use a "Certified for Windows" logotype, which certifies that the hardware or software has had some share of testing by Microsoft to ensure compatibility. The actual logo used depends on the version of Windows.

For device drivers passing the WHQL tests, Microsoft creates a digitally signed certification file that, when included in the driver installation package allows installation on 64 bit versions of Windows Vista and prevents 32 bit versions of Vista, and all versions of Windows XP from displaying a warning message that the driver has not been certified by Microsoft. A company can choose to sign their own drivers rather than go through the WHQL testing process. These drivers would not qualify for the "Certified for Windows" logos, but they would install on 64 bit versions of Vista and install without a warning message on 32 bit versions of Vista.However, it will not install without a warning message on Windows XP.

Some device drivers that have passed the WHQL tests are also made available for download using Windows Update.

 
 

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