MCIMX27 Datasheet, PDF (1423/1650 Pages) Freescale Semiconductor, Inc – Multimedia Applications Processor

enhanced Multimedia Accelerator Light (eMMA_lt)
Matrix
Eqn
Co-
Efficient
B1 1 or 7
(Set B)
B0 1 or 7
(Set B)
Table 41-4. YUV to RGB CSC Equations (continued)
Video
Range
Input to CSC and
Notation
Matrix
Register Values
1
Y’U’V’
R = Y’ + 1.5749 * (V’-128)
C0 = 8’b1000 0000
Y’ ranges from
G = Y’ – 0.1875 * (U’-128) – 0.4682 * (V’-128) C1 = 8’b1100 1001
0-255
B = Y’ + 1.8554 * (U’-128)
C2 = 8’b0001 1000
U’ ranges from
C3 = 8’b0011 1100
0-255
C4 = 9’b0 1110 1101
V’ ranges from
X0 = 1’b0
0-255
0
Y’Cr’Cb’
R = 1.164(Y’-16) + 1.793 * (Cr’-128)
C0 = 8’b1001 0100
Y’ ranges from
G = 1.164(Y’-16) – 0.533 * (Cr’-128) – 0.213 * C1 = 8’b1110 0110
16-235
(Cb’-128)
C2 = 8’b0001 1011
Cr’ ranges from B = 1.164(Y’-16) + 2.112 * (Cb’-128)
C3 = 8’b0100 0100
16-240
C4 = 9’b1 0000 1110
Cb’ ranges from
X0 = 1’b1
16-240
The correct matrix has to be selected based on the video_range and matrix_coefficient for color space
conversion.
41.3.2 Input Interface
The PP reads IYUV or YV12 data from external memory. Quantization Parameter (QP) data is required if
Deblock and/or De-ring operations are selected. Figure 41-4 shows an example layout for QCIF frames to
be processed by the PP.
The input Y, U, V, and QP data are expected in 4 sections of memory. The first data in every row starts
with a new word. When the row size is not a multiple of 4 bytes, the last few pixels in a row will not occupy
a full word and the extra bytes, if any, in the last word are ignored.
The PP expects one QP byte per macroblock (MB). Only the lower 5 bits of a QP byte are used and the 3
most significant bits must be set to 0. The first QP in every row starts with a new word and four QP bytes
from 4 adjacent MBs in a row are packed into one word. When the number of MBs in a row is not a
multiple of 4, then the extra QP bytes in the last word of a QP row are ignored.
Data is stored in the memory in the order of natural scan lines. For Y, U, and V data, it is permitted that
the distance between the start of two neighboring lines (line stride) is greater than the number of pixels in
a line—that is, there could be fixed number of unused words between the end and the beginning of every
two neighboring lines. However, unused words are not permitted for QP data.
Each row in Figure 41-4 represents a word in memory. Y(j,i) denotes Y data of pixel row j and column i.
Layout of U and V data is similar to that of Y data. The figure shows there can be unused space in memory
between rows. This parameter is controlled by the Input Line Stride parameter and applies only to Y, U,
and V data in the frame. The start of Y, U, and V data can be anywhere in addressable memory.
MCIMX27 Multimedia Applications Processor Reference Manual, Rev. 0.2
Freescale Semiconductor
41-9