Information Technology Reference
In-Depth Information
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Zero-tree wavelet coding of still pictures
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Dynamic 2D mesh coding of synthetic objects and facial animation
modeling
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Quarter-pixel motion compensation and global motion compensation
Ghanbari et. al. in [2] further says that H.264 is a state-of-the-art video codec,
standardized in 2003 and is suitable for a wide range of applications. This codec
has the following features:
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High profile for HDTV and Blue-ray disc storage support a wide set of
applications.
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Baseline profile is intended for applications with limited computing
resources, such as video-conferencing and mobile applications.
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The main profile was intended for broadcast TV and storage
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The Extended profile is intended for streaming applications, with robust
coding, trick modes, and server switching.
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Fixed-point implementation and the first network friendly coding
standard.
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Higher computational complexity but better coding efficiency than
previous standards.
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An increased range of quantization parameters, and employs Lagrangian
optimized rate control.
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The components of the target bit-rate in a rate-distortion function are
divided between the individual coding parts in such a manner that
maximum reduction in distortion is achieved at the expense of minimal
increase in the bit rate.
Wavelet based coding has been used in JPEG 2000 and MPEG-4 for coding
images. However, there is no Wavelet based video coding standard yet. Wavelet-
based video encoders have attracted significant attention amongst researchers
recently, due to the arrival of efficient quantization algorithms and associated
coders [2]. Ghanbari et al further says in [2] that the principal attraction of wavelet
transform is its inherent property of transformation that lends itself to scalable
coding at entropy coder. Scalability is a natural part of the wavelet based codec, in
that the coding gain increases at higher scalability levels. However, in DCT-based
codecs, larger levels of scalability reduce its compression efficiency. The wavelet
may also outperform the DCT in compactness.
Ghanbari et al in [2] also adds that the wavelet-based video coding has come to
prominence and will be part of future codecs due to increased demand for
scalability in video coding. In Wavelet Transform, more specifically, Haar
transform is used for scalable coding between pictures (not for residual MBs) in
H. 264. Haar transform also exhibits the properties of the orthogonal transforms.
Ghanbari et al in [2] tells about another advantage of wavelet transform. It
comes with the fact that it is applied to a complete image rather than a block. The
disadvantage of block based processing is the discontinuities that occur at block
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