Cryptography Reference
In-Depth Information
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t+2D
JSVM3.0
STool
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Spatio-Temporal and Quality Resolution
Fig. 3.20.
Comparison of wavelet schemes with AVC-based SVC for the Mobile
sequence [32].
the open-loop structure is that it eases the R-D optimization for selecting
parameter values.
The current wavelet video schemes need improvement in some areas. The
objective SNR is often good but the subjective image quality at lower bit rates
is not as good as the images produced by AVC. This is often due to the low
quality of the low pass temporal filtered pictures owing to incorrect motion
vectors and/or down-sampling filters. High quality temporal references pro-
vide better coding e
ciency but they induce drifting errors at low rates when
high quality references are not available. A powerful tool, intra-prediction in
AVC, is not well adopted by the wavelet scheme.
Overall, the wavelet video scheme is a relatively young structure in video
coding. It seems to have a good potential in providing very good coding e
-
ciency on the high-definition. That is in high rate, high resolution pictures.
It offers also a high number of combined spatial-temporal scalable levels and
extremely fine-grain SNR scalability. It may also do a better job for non-
dyadic spatial scalability. With an open-loop structure, it can be more robust
in coping with transmission errors. Finally, it can be made compatible with
the JPEG2000 standard for single image compression [25].
