Re: Indeo information

On Sun, 21 Dec 2003, Benjamin Larsson wrote:

> *Intel's INDEO Video Compression Algorithm.* Intel's proprietary INDEO
> video compression algorithm is used primarily for video presentations on
> personal computer (PC) desktops. It employs color subsampling, pixel
> differencing, run-length encoding, vector quantization, and variable
> word-length encoding. The chrominance components are heavily subsampled.
> For every block of 4-by-4 luminance samples, there is a single sample of
> Cb and Cr. Furthermore, samples are shifted one bit to convert them to
> 7-bit values. The resulting precompression format is called YVU9,
> because on average there are 9 bits per pixel. This subsampling alone
> yields a reduction of 9/24. Run-length encoding is employed to encode
> any run of zero pixel differences.

	This sounds more like Indeo 3.

[...]
> optimized for low-bit-rate, ISDN-based connections and, unlike its
> desktop compression cousin, is transform-based. It is an interframe
> algorithm that uses motion estimation and a 4:1 chrominance subsampling
> in both directions. Spatial and temporal loop filters are used to remove
> high-frequency artifacts. The transform used for converting spatial data
> to frequency coefficients is the slant transform, which has the
[...]

	This sounds like Indeo 4, based on 2 facts: 1) the slant
transform, and 2) 4:1:0 colorspace; Indeo 5 outputs 4:2:0, if memory
serves.

--
	-Mike Melanson



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