Video Stream Coding Technology
Sub-band Coding (DCT/Wavelet/ Lapped):
- Divide the signal into independent frequency components by the use of linear filters.
- Control the precision of the the frequency coefficients based on resolution.
Pyramid Coding:
- A low pass filter separates a low-resolution image from a wideband signal. The ‘lows’ are coded. The process is repeated for the difference between the ‘original’ and the ‘low’.
- Take only adequate sub-images from the top of the pyramid to obtain the desired resolution.
Vector Quantization
- Less codebook vectors for low resolution regions
Fish-Eye Transforms
- Spatially spread/compress the pel space before compression based on priority.