Visual Layers
An MPEG-4 visual scene consists of one or more video objects. Currently, the most common video object is a simple rectangular frame of video.
Each video object may have one or more layers to support temporal or spatial scalable coding. This enables the reconstruction of video in a layered manner, starting with a base layer and adding a number of enhancement layers. Where a high degree of scalability is needed, such as when an image is mapped onto a 2D or 3D object, a wavelet transform is available.
The visual bitstream provides a hierarchical description of the scene. Each level of hierarchy can be accessed through the use of unique start codes in the bitstream.
Visual Object Sequence (VS)
This is the complete scene which contains ...
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