[x264-devel] x264 Intra prediction mode

[Jason Garrett-Glaser]

On Mon, Dec 10, 2012 at 7:22 AM, eloise vidal <eloise.vidal at gmail.com> wrote:
> Hi,
> I have a question about the Intra modes used by x264.
> I noticed that 3 modes are used in addition to the standardized modes (4
> modes(fashions) for blocks 16x16 and 9 modes(fashions) for blocks 4x4):
> DC_LEFT, DC_TOP and DC_128.
>
> Are these three modes specific to x264? And if it is the case, how the
> encoded stream can be in accordance with the standard H.264?

There are 4 possible DC modes in progressive H.264; which one is
selected depends on the availability of neighbors to predict from.
x264 separates them for reasons of simplicity, the spec doesn't, but
the result is equivalent.

Jason