smart-e 4K-RX9000, Руководство пользователя

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4K-9000 USER MANUAL V1.1
© 2018 Smart-e (UK) Ltd www.smart-e.co.uk PAGE | 47
21 FURTHER CONSIDERATIONS
21.1 BANDWIDTH CALCULATION
The bandwidth required for a HDMI signal can be calculated in the following method.
Total Horizontal Pixels X Total Vertical Pixels = Pixels per Frame
Pixels Per Frame X Refresh Rate = Pixels per Second
Pixels per Second X Colour Depth Factor X 10 bits per TMDS clock
= Bandwidth per Channel x 3 TMDS data channels = Total Bandwidth
The total number of horizontal and vertical pixels is not simply the resolution, for example 1920x1080, it also
must include the blanking areas which are to the left and above of the active pixel area. For a 1080p image
the total number of pixels are 2200x1125. These blank areas are referred to as the horizontal blanking and
vertical blanking areas. They are used to separate the active areas of frames, a process vital in old analogue
broadcast systems. HDMI formats use these areas to send control and data signals, such as the colour depth
information for the frame allowing the screen to correctly map the incoming colour data to the active area of
the screen. The below example shows an example of a 1080p @60Hz image including blanking.
The sizes of these blanking areas are defined in standards developed by the Society of Motion Picture and
Television Engineers (SMPTE), the standard for 1080p @60Hz is SMPTE 424M. A standard exists for every
standard resolution. From this example we can now calculate the bandwidth required for a 1080p @60Hz
transmission at any colour depth, below is an example assuming 12-bit colour depth.