SiI9127A/SiI1127A HDMI Receiver with Deep Color Output
Data Sheet
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SiI-DS-1059-D 13
Up Sample/Down Sample
Additional logic can convert from 4:2:2 to 4:4:4 (8/10/12-bit) or from 4:4:4 (8/10/12-bit) to 4:2:2 YCbCr format. All
processing is done with 14 bits of accuracy for true 12-bit data.
Deep Color Support
The HDMI 1.3 Specification introduces Color Depth modes greater than 24 bits, known as Deep Color modes, to the
HDMI system architecture. The Deep Color modes employ a new pixel packing scheme to enable the extra bits of
higher color depth data to be carried over the existing TMDS data encoding scheme. Currently, three Deep Color
modes are defined: 30-bit, 36-bit, and 48-bit. The SiI9127A/SiI1127A receiver supports two of these three Deep Color
modes; 30-bit, and 36-bit modes. In addition, each Deep Color mode is supported up to 1080p HD format.
For Deep Color modes, the TMDS clock is run faster than the pixel clock in order to create extra bandwidth for the
additional bits of the higher color depth data. The increase in the TMDS clock is by the ratio of the pixel size to 24 bits,
as follows:
30-bit mode: TMDS clock = 1.25x pixel clock (5:4)
36-bit mode: TMDS clock = 1.5x pixel clock (3:2)
Because the receiver supports 36-bit mode at 1080p, the highest TMDS clock rate it supports is therefore 225 MHz.
When in Deep Color mode, the transmitter periodically sends a General Control Packet with the current color depth
and pixel packing phase information to the receiver. The receiver captures the color depth information in a register,
which the firmware can then use to set the appropriate clock divider to recover the pixel clock and data.
xvYCC
The SiI9127A/SiI1127A receiver adds support for the extended gamut xvYCC color space; this extended format has
roughly 1.8 times more colors than the RGB color space. The use of the xvYCC color space is made possible because of
the availability of LED and laser based light sources for the next generation displays. This format also makes use of the
full range of values 1 to 254 in an 8-bit space instead of 16 to 235 in the RGB format. The use of xvYCC along with Deep
Color helps in reducing color banding and allows display of a larger range of colors than is currently possible.
Color Space Conversion
Color space converter (CSC) blocks are provided to convert RGB data to Standard-Definition (ITU.601) or High-
Definition (ITU.709) YCbCr formats, and vice-versa. To support the latest extended-gamut xvYCC displays, the
SiI9127A/SiI1127A receiver implements color space converter blocks to convert RGB data to extended-gamut Standard-
Definition (ITU.601) or High-Definition (ITU.709) xvYCC formats, and vice-versa.
RGB to YCbCr
The RGBYCbCr color space converter (CSC) can convert from video data RGB to standard definition (ITU.601) or to
high definition (ITU.709) YCbCr formats. The HDMI AVI packet defines the color space of the incoming video.
YCbCr to RGB
The YCbCrRGB color space converter is available to interface to MPEG decoders with RGB-only inputs. The CSC can
convert from YCbCr in standard-definition (ITU.601) or high-definition (ITU.709) to RGB.
3D Video Formats
The SiI9127A/SiI1127A receiver has support for the 3D video modes described in the HDMI 1.4 Specification. All modes
support RGB 4:4:4, YCbCr 4:4:4, and YCbCr 4:2:2 color formats and 8-, 10-, and 12-bit data width per color component.
Table 3.2 on the next page shows only the maximum possible resolution with a given frame rate; for example, Side-by-
Side (Half) mode is defined for 1080p60, which implies that 720p60 and 480p60 are also supported. Furthermore, a frame
rate of 24 Hz also means that a frame rate of 23.98 Hz is supported and a frame rate of 60 Hz also means a frame rate of
59.94 Hz is supported. The input pixel clock changes accordingly.
When using Side-by-Side formats the use of 4:2:2 to 4:4:4 up-sampling and 4:4:4 to 4:2:2 down-sampling should not be
enabled as it may result in visible artifacts.
Video processing should be bypassed in the case of L + depth format.