Hardware Reference
In-Depth Information
80
Decoding time of stream processing
unit in the stream-rate domain
Number of bits/picture
60
33.3ms(=Decoding time of
Image processing unit in
the pixel-rate domain)
40
20
40Mbps
0
0
5
10
15
20
25
30
35
40
Picture number
Fig. 3.77
Stream processing unit's decoding time for an H.264 40-Mbps full HD video stream
running at 30 frames per second (fps)
a
S
0
S
1
S
2
S
3
S
4
P
0
P
1
P
2
P
3
P
4
Delay
Time slot
Time
Without intermediate stream buffering
b
S
0
S
1
S
2
S
3
S
4
P
0
P
1
P
2
P
3
P
4
Time slot
No delay
Time
S
n
: Stream decoding for picture
n
P
n
: Pixel decoding for picture
n
Intermediate stream buffering
Fig. 3.78
Parallel operation in picture-level pipeline in stream-rate domain and pixel-rate domain
domain. Except for stream decoding S0 for Picture 0, stream and pixel decoding are
processed in parallel. In Fig.
3.78a
, that is, without an intermediate stream buffer, if
the decoding time of S2 is larger than the decoding time of P1, it causes a delay in
the start of P2. To shorten the S2 decoding time, we can increase the operating
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