Graphics Reference
In-Depth Information
Table 3. Intra prediction mode decision of luma 16×16 blocks
prediction mode of Chroma 8×8 blocks
Main candidate modes of luma 16×16 block
Mode 0
Mode 2 (DC)
Mode 1
Mode 1 (Horizontal) + Mode 2 (DC)
Mode 2
Mode 0 (Vertical) + Mode 2 (DC)
Mode 3
Mode 3 (Plane) + Mode 2 (DC)
In order to cut down the number of the intra prediction modes and reduce high cal-
culation burden, we choose the Simple Sum of Absolute Difference (SAD) calcula-
tion as the rate control model, which is used to determine the best intra prediction
mode according to the principle of the minimum SAD value before coding.
.
SAD
=
original
(
x
,
y
)
predict
(
x
,
y
)
(6)
(
x
,
y
)
MB
k
While the position (x,y) represents the location of the luma pixels in the macrob-
lock or sub-block, original(x,y) represents the original pixel value, predict(x,y)
represents the prediction pixel value.
2.5
The Comparison between the New Algorithm and Original Algorithm of
Intra Prediction
Combine with the original algorithms, a new mode decision algorithm for H.264
intra prediction is proposed. The computational complexity comparison of the two
algorithms is shown below as table 4 gives.
Table 4. The computational complexity comparison of two algorithms
Chroma 8×8 intra
prediction
luma 4×4 intra
prediction
luma 16×16 intra
prediction
Modes
New
1 or 2
2
1
Original
4
9
4
According to the above analysis, it is evident that the new mode decision algorithm
can reduce the calculation times to 1×(16×2)=32, 1×(16×2+1)=33, 1×1=1,
2×(16×2)=64, 2×(16×2+1)=66 or 2×1=2. A significant operation efficiency improv-
ing can be achieved.
3
FPGA Design of H.264 Intra Prediction Hardware
Architecture
From the above analysis, the hardware architecture of the proposed algorithm can be
designed as shown in figure 1.
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