[x264-devel] I444 support

[Loren Merritt]

On Thu, 29 Nov 2007, List, Peter wrote:

> As far as I know, one of the reasons for DCI to decide for JPEG2000 and
> against H.264 was the inability of H.264 to produce COMPLETELY
> transparent quality at low compression rates at that time. Because of
> that phenomena the gains of temporal prediction in H.264 were to a large
> extend eaten up by the necessity to reduce qp more than expected to gain
> the same visual quality than JPEG2000.

That surprises me. In my experience, any intra codec (including jpeg2k) 
requires lower quantizer than any inter codec (including h264 main 
profile) for a given perceptual quality. Because intra artifacts are 
temporally incoherent. A near-static region of the video becomes 
non-static when consecutive I-frames are quantized differently, which is 
far more visible than any dct or wavelet artifact by itself.

--Loren Merritt