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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