Re: Indeo information

On Sun, 21 Dec 2003, Benjamin Larsson wrote:

> Found this page on the internet by accident:
>
> http://www2.ncsu.edu/eos/service/ece/project/succeed_info/larettin/thesis/ch2.html
>
> Intresting parts follow
>
> 'Indeo is a video compression technique designed by Intel. It evolved
> from DVI (Digital Video Interactive) technology. Indeo starts off with
> YUV input, U and V subsampled 4:1 both horizontally and vertically.
> Indeo supports motion estimation, using the previous frame to predict
> values for the current frame and only transmitting data if the
> difference is significant. Transform encoding is done using a 8x8 Fast
> Slant Transform (FST) in which all operations are either shifts or adds
> (no multiplies). Quantization and run-length/entropy encoding are used
> as in previous algorithms. Indeo specifies that the encoded bit stream
> be a maximum of 60% of the input data, therefore compression is
> guaranteed to be at worst 1.7:1.'
>
> and this paper was written in 1995, so the indeo codec he talks about
> could be 3.1/3.2 or even 2.1.

	Try to reconcile this with ffmpeg's Indeo 3 source. I doubt that
you will find anything resembling a slant transform. Indeo 3 (and 2, I
believe) are supposed to be vector quantizers. I am pretty sure that the
slant transform actually applies to Indeo 5, possible Indeo 4 as well.  I
know that version 4 and 5 were available as of 1997. The earliest software
I have that uses version 4 has a copyright date of 1996. That paper could
have also been written based on an Intel press release discussing upcoming
technology.

--
	-Mike Melanson



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