B-MAC

B-MAC is a form of analog video encoding, specifically a type of Multiplexed Analogue Components (MAC) encoding. MAC encoding was designed in the mid 80s for use with Direct Broadcast Satellite systems. Other analog video encoding systems include NTSC, PAL and SECAM. Unlike the Frequency-Division Multiplexing (FDM) method used in those, MAC encoding uses a Time-Division Multiplexing (TDM) method. B-MAC was a proprietary MAC encoding used by Scientific-Atlanta for encrypting broadcast video services; the full name was "Multiple Analogue Component, Type B".

B-MAC is a form of analog video encoding, specifically a type of Multiplexed Analogue Components (MAC) encoding. MAC encoding was designed in the mid 80s for use with Direct Broadcast Satellite systems. Other analog video encoding systems include NTSC, PAL and SECAM. Unlike the Frequency-Division Multiplexing (FDM) method used in those, MAC encoding uses a Time-Division Multiplexing (TDM) method. B-MAC was a proprietary MAC encoding used by Scientific-Atlanta for encrypting broadcast video services; the full name was "Multiple Analogue Component, Type B". In MAC color is encoded using the YPbPr color space. Luma ( Y' ) is derived from red, green, and blue ( R', G', B' ) after gamma-correction (formula similar to PAL): Y'= 0.2997R' + 0.587G' + 0.1145B' Chrominance is computed based on B-Y and R-Y differences, generating two compressed and weighted color-difference signals, P{\scriptstyle\text{B}} and P{\scriptstyle\text{R}} . The Y' signal range is between -0.5 and 0.5 volts while P{\scriptstyle\text{B}} and P{\scriptstyle\text{R}} signals vary between -0.65 to 0.65 volts. The following table lists the main technical parameters of B-MAC variants:

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