Hi all,

I'm new to the forum and new to H.264. My degree is in electronic communication engineering (in the '80s) and my job needs me to get right up to speed with H.264.
I've been reading about sampling formats YCrCb such as sampling format 4:4:4 that codes one of the three channels as luma and the other two channels being coded as chroma using less efficient tools.

This approach is said to be such that when the input to the codec is in the 4:4:4 format with full resolution in every input component, coding two out of the three input components with less the effective chroma coding algorithm results in using more bits in those two channels. The solution is said to be to use the same algorithm, the luma algorithm, for all channels, that is, to use a common predictor.

However, what did people do before it was realised that luma should be encoded differently to chroma (due to the human vision system perceiving luma better than chroma so code luma at a higher resolution). Way back when, were the YCrCb components all coded using the same predictor or using the same technique? If so, can you point me to any technical information on that?

Many thanks, Harry