Cryptography Reference
In-Depth Information
Copyright information
MPEG encoder
Watermarking
process
Watermarked
frame
Encoding
process
(DCT, etc.)
Encoded
watermarked
video
Original
video
Motion
estimation
d ,
v
Motion information
(a) Overall system structure
Copyright information
Watermarked
frames
Original
frames
(
f
)
y
(
f
)
Embedding process
y'
r
i, j
Embedding control process
r
i, j
- operation
r
i, j
=
f (d ,
v
,
s
i, j
)
s
i, j
Intra-frame
analysis
d ,
v
Motion information
From MPEG encoder
(b) Watermarking process
Fig. 7.5.
System structure of motion-adaptive embedding technique.
The embedding control process can be used in various WM embedding
systems because it is combined with the embedding process only though r
i,j
.
This can be calculated independently of the embedding process.
Process Flow
The process flow of the 1-bit-WM embedding is now described. Steps E2 and
E3 are embedding control steps, and Steps E4 and E5 are embedding steps.
For multiple-bit embedding, each frame is divided into regions, and the 1-bit
embedding process is then applied to each region.
Step E1: Do the following steps over the range f =1, 2,.
Step E2: Calculate s
i,j
from luminance set y
(f )
of the input frame.
Step E3: Calculate r
i,j
from v, d (calculated by the motion estimation func-
tion of the encoder), and s
i,j
.
Step E4: Determine WM strength µ
(f )
i,j
at pixel (i, j) of frame y
(f )
:
r
i,j
µ
(f )
i,j
=
Q,
(7.6)
i,j
r
i,j
