Hi, On 13-Jun-01 Christopher Ross wrote: > > The 4:2:0 is a standard format, derived from CCIR-601 (1982). > To quote Benoit (ch2 Digitization of Video Signals): > > For applications that are less demanding in terms of resolution, > and in view of the bit-rate reduction, a certain number of by-products > of the 4:2:2 standard have been defined as follows: > > The 4:2:0 format > This format is obtained from the 4:2:2 format by using the same > chroma samples for two successive lines, in order to reduce the > amount of memory required in processing circuitry while at the > same time giving a vertical resolution of the same order as the > horizontal resolution. Luminance and horizontal chrominance > resolutions are the same as for the 4:2:2 format > [...snip...] [snip] Okay, interesting stuff, but it still fails to address the most basic question: in what order are the bytes (supposed to be) arranged? It seems nobody dared to propose a specific format. > Oh, in searching Amazon to get the above reference for you I found > that of the two customer reviews the second (5*) is also from a Philips > employee. This is clearly the book we crib all our stuff from ;-) *heh* > I've tried but failed to find the ITU specification itself online (not > least > because their website seems to hate Mozilla - but that's a different > problem). There's a useful summary (with a link to the 4:2:0 variation) > at http://www.electric-words.com/dict/9/601ccir.html You have to pay for most ITU documentation, and that´s why you won´t find it online. And they aren´t cheap. I recall looking for documentation on the H.263 protocol, etc. and arrived at their site (www.itu.ch), and found that in order to get enough information about video conferencing stuff, I´d need a dozen pieces of documentation, ranging in price from CHF 20 to CHF 65 (Swiss franks). - Nemosoft ----------------------------------------------------------------------------- Try SorceryNet! One of the best IRC-networks around! irc.sorcery.net:9000 URL: never IRC: nemosoft IscaBBS (bbs.isca.uiowa.edu): Nemosoft >> Never mind the daylight <<
