Renesas SH7781 User Manual
Page 1050
20. Graphics Data Translation Accelerator (GDTA)
Rev.1.00 Jan. 10, 2008 Page 1020 of 1658
REJ09B0261-0100
(1)
Estimated Image Generation Function
The following shows an outline of the estimated image generation function.
Output frame
Y pointer (current)
Output frame
U pointer (current)
Output frame
V pointer (current)
Past frame
Y pointer
Past frame
U pointer
Past frame
V pointer
Future frame
Y pointer
Future frame
U pointer
Future frame
V pointer
(9) Estimated
image writing
(5) Data
reading
Image data for one frame
Frame width
Y padding
U (current)
V (current)
U (past)
V (past)
Y (future)
U (future)
V (future)
Y (past)
Y (current)
Base point
Base point
Output
(current)
Output
target position
Target position (mbcol, mbrow)
Comparison point
(+Recon_right, down)
(6) Half-pixel correction processing
Recon_down
(ne
g
ative value indicates reverse direction)
Invalid data
Y: 16
× 16 dot
U: 8
× 8 dot
V: 8
× 8 dot
Input
image
(half-pixel)
Recon_right (negative value indicates reverse direction)
Y: 17
× 17 dot
U: 9
× 9 dot
V: 9
× 9 dot
For half-pixel processing,
get data for a block with one
extra dot according to motion
vector values
Hardware performs processing
as is even when in padding part
Y0 (128 bytes)
Y1 (128 bytes)
Y2 (128 bytes)
Y3 (128 bytes)
U (128 bytes)
V (128 bytes)
Buffer RAM 1
(8) Estimated-image generation
(7) IDCT data
reading
IDCT data
Y: 16
× 16 dot
U: 8
× 8 dot
V: 8
× 8 dot
Y: 16
× 16 dot
U: 8
× 8 dot
V: 8
× 8 dot
Y: 17
× 17 dot
U: 9
× 9 dot
V: 9
× 9 dot
Y: 16
× 16 dot
U: 8
× 8 dot
V: 8
× 8 dot
Correction processing result (Y: 16
× 16, U/V: 8 × 8)
Data after half-pixel
correction
IDCT data
Data to be written back to the current target position
(result of forward macroblock processing)
Ч 16
Ч 16
Ч 16
Ч 16
Ч 16
Ч 16
Ч 17
Ч 17
Input data for one macroblock
Correction
case 3
Correction case 4
Correction
case 1
Correction
case 2
Each frame pointer should point to an address on a 16-byte boundary
for Y and 8-byte boundary for U and V.
8-bit saturation
calculation
(0
≤ x ≤ 255)
(1) Calculation of output position (first row)
(2) Calculation of output position (nth row)
(3) Calculation of input position (first row)
(4) Calculation of input position (nth row)
A
B
E
D
A'
B'
D'
C'
a
b
d
c
A''
B'
D'
C'
mbcol
mbrow
Frame hei
g
ht
(mbcol, mbrow)
DDR2-SDRAM
Figure 20.6 Outline of Estimated Image Generation Function