Referring to FIG. 11, it can be seen that a difference in picture characteristics between luma and chroma is present in the same picture. Therefore, in addition to the offset of a signal in luma pixels, the offset of a signal in chroma pixels may be independently transmitted in consideration of the characteristic difference between a luma signal and a chroma signal as in the example illustrated in FIG. 11. For example, in consideration of the number of luma pixels and the number of chroma pixels, an offset may be applied to the chroma pixels with a bit depth substantially smaller than the bit depth in the luma pixels.
For example, when the range of a chroma signal, that is, the pixel value range of the chroma pixels, is from 0 to 2N?1 (where N is a bit depth), the magnitude of the entire bit depth, that is, the pixel value range, may be divided as in the example illustrated in FIG. 12 or 13.
FIG. 12 is a diagram schematically illustrating an example where a band offset is applied to only some bands of the total bands for the chroma pixels.
Referring to FIG. 12, chroma pixels may be allocated to the central bands including K bands at the center out of the total 2*K bands and the band offset may be applied thereto.
