Methods and Apparatuses of Video Encoding or Decoding with Adaptive Quantization of Video Data

An apparatus for performing video coding, comprising:

• a computer processor configured for receiving video data;
• and programming executable on the computer processor for video coding by performing steps comprising:
• receiving the video data having a luminance (luma) component and at least one chrominance (chroma) component;
• performing inter prediction and/or intra prediction for reducing temporal and/or spatial redundancies within the received video data;
• determining a luma Quantization Parameter (QP) for the luma component;
• deriving a chroma QP bias from an intermediate QP index, wherein the intermediate QP index is computed by clipping a sum of the luma QP and a chroma QP offset parameter to a specified range;
• calculating a chroma QP by subtracting the chroma QP bias from the luma QP or by subtracting the chroma QP bias from the intermediate QP index;
• performing a transform processing during encoding of the received video data and/or performing an inverse transform processing during reconstruction of encoding or decoding of the received video data;
• and
• performing a quantization processing during encoding of the received video data and/or performing an inverse quantization processing during reconstruction of encoding or decoding of the received video data for the luma component utilizing the luma QP and for the chroma component utilizing the chroma QP.

A non-transitory computer readable medium storing program instruction causing a processing circuit of an apparatus to perform video coding method, and the method comprising:

• receiving the video data having a luminance (luma) component and at least one chrominance (chroma) component;
• performing inter prediction and/or intra prediction for reducing temporal and/or spatial redundancies within the received video data;
• determining a luma Quantization Parameter (QP) for the luma component;
• deriving a chroma QP bias from an intermediate QP index, wherein the intermediate QP index is computed by clipping a sum of the luma QP and a chroma QP offset parameter to a specified range;
• calculating a chroma QP by subtracting the chroma QP bias from the luma QP or by subtracting the chroma QP bias from the intermediate QP index;
• performing a transform processing during encoding of the received video data and/or performing an inverse transform processing during reconstruction of encoding or decoding of the received video data;
• and
• performing a quantization processing during encoding of the received video data and/or performing an inverse quantization processing during reconstruction of encoding or decoding of the received video data for the luma component utilizing the luma QP and for the chroma component utilizing the chroma QP.