AC coefficients

In the Wikipedia JPEG page describing DCT, the (0,0)
coefficient is called the DC coefficient, as usual.
The others are then called AC coefficients.

Somehow I don't ever recall them being called
AC coefficients before, and it sounds funny to me.

Is that really what they are called?

-- glen

On Mar 24, 9:33&#4294967295;pm, glen herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
> In the Wikipedia JPEG page describing DCT, the (0,0)
> coefficient is called the DC coefficient, as usual.
> The others are then called AC coefficients.
>
> Somehow I don't ever recall them being called
> AC coefficients before, and it sounds funny to me.
>
> Is that really what they are called?
>
> -- glen

In the image compression community (MPEG-2, H.264, and so on) this is
very common usage. I believe this terminology is directly used in some
of the ISO/IEC specifications; oftentimes the DC coefficient is
singled out for special treatment distinct from that of the rabble of
AC coefficients.

After all, if it's not DC, then it has to be AC, right... ?

 - Kenn