The video coding structure 100 is encoded as a bitstream in some embodiments. Such a bitstream is based on an established video coding format such as the HEVC/H.265 standard or MPEG-4 AVC/H.264 standard. A picture under the H.265 standard can include one or more slices, and each slice can have one of more coding tree units (CTUs). Further, each CTU can be sub-divided into blocks. H.265 also allows the definition of luma quantization groups for quantizing/de-quantizing luma components. Each quantization group allows the derivation of a luma quantization parameter that is specific to the video data units within the quantization group. Once derived, the luma quantization parameter is then used to perform quantization of luma DCT coefficients. Under the H.265 standard, chroma quantization parameters are derived from luma quantization parameters based on offset values provided in the picture or slice layer of an H.265 compliant bitstream. The video coding structure 100 provides chroma QP offset signaling or specification that is in addition to the picture/slice layer chroma QP offsets allowed by the H.265 standard.

The chroma QGs 141-143 are defined ranges in the video coding structure 100. Each of the QGs 141-143 is associated with its own set of chroma QP offset values 141-143. In some embodiments, a quantization group can be a group of video data units that share a same set of QP values. In some embodiments, the signaling for chroma QP offsets in a QG is applied to all video data units within the QG. In some embodiments, the QP offsets are applied starting from the first signaled chroma residual information onward. Any areas preceding the signaling are not associated with the signaled chroma QP offset. In other words, the QG may be “fragmented”.