Graphics Reference
In-Depth Information
Table 11.4
Comparison of H.264/AVC and HEVC encoders
ISSCC'09[
18
]
VLSIC'12[
43
]
This work
Resolution
4096x2160@24fps
7680x4320@60fps
8192x4320@30fps
Throughput
212Mpixels/s
1991Mpixels/s
1062Mpixels/s
Standard
H.264 High @ Level 5.1
H.264 Intra
HEVC
Search range
[255,+255]/[255,+255]
N/A
[512,+511]/[128,+127]
(Predictor Centered)
Technology
TSMC 90nm
e-Shuttle 65nm
TSMC 28nm HPM
3.95x2.90mm
2
3.95x2.90mm
2
5x5mm
2
Core size
Gate count
1732K
678.8K
8350K
Power
522mW@280MHz
139.9mW@280MHz
708mW@312MHz
Table 11.5
Summary of modifications
Module
Modifications
BD-Rate[%]
BD-PSNR[dB]
Intra
1. 12-Candi. Fast Intra Prediction
1.03
0:03
2. Skip I64
3. Hybrid Open-Close Loop
Inter
1. Parallel-PU IME
6.08
0:19
2. Two-AMVP Coarse-fine Search
3. 3-bit Pixel Truncation
4. Quarter Sub-sampling
5. 25-Candi. Central Quarter FME
Transform
1. Fixed Transform Size
3.02
0:08
RDO
1. PU-level Early Mode Decision
7.18
0:20
2. CFBAC Bit Estimator
CABAC dependency. Multiple parts of frame (i.e. multiple CTUs) can be coded
at the same time if these configurations are enabled. In addition, multiple sets of
CABAC engines can be used to make the utilization even higher.
11.8.1
Implementation Results for Encoder Test Chip
An HEVC encoder test chip capable of encoding 8K UHDTV is implemented
in [
36
]. The encoder is designed based on HM4. The modifications relative to
HM is summarized in Table
11.5
. The primary gate count of the encoder is listed
in Table
11.6
. Note that frame-level loop filter in HM4 is implemented in this
encoder; however, as frame-level loop filter is not required in the final standard, the
gate count would be significantly reduced for an HEVC-compliant implementation.
Comparisons to previous AVC encoders is shown in Table
11.4
. The total bandwidth
is 6:80 GB/s. Compared to Ding's previous H.264/AVC encoder in ISSCC'09 [
18
],
the resolution is four times higher, but the bandwidth usage is only increased by
37 %. To compare with H.264/AVC encoders, the rate-distortion curves for HM4,
JM (H.264 reference software), and the presented hardware encoder in encoding 8K
