Method of encoding an image into a coded image, method of decoding a coded image, and apparatuses thereof

A method of encoding an image into a coded image, the method comprising:

• determining a quantization parameter for a processing unit of the image;
• and
• determining if a prediction mode included in header information is a first prediction mode,
• wherein if the header information indicates that the prediction mode is the first prediction mode, the method further comprises:
• modifying the determined quantization parameter using a quantization offset parameter for the first prediction mode;
• and
• performing a quantization process for the processing unit using the modified quantization parameter, and
• wherein if the header information indicates that the prediction mode is a second prediction mode which is different from the first prediction mode, the method further comprises:
• performing a quantization process for the processing unit without using the quantization offset parameter for the first prediction mode.

A method of decoding a coded image, the method comprising:

• determining a quantization parameter for a processing unit of the coded image;
• and
• determining if a prediction mode included in header information is a first prediction mode,
• wherein if the header information indicates that the prediction mode is the first prediction mode, the method further comprises:
• modifying the determined quantization parameter using a quantization offset parameter for the first prediction mode;
• and
• performing an inverse quantization process for the processing unit using the modified quantization parameter, and
• wherein if the header information indicates that the prediction mode is a second prediction mode which is different from the first prediction mode, the method further comprises:
• performing an inverse quantization process for the processing unit without using the quantization offset parameter for the first prediction mode.

An apparatus for encoding an image into a coded image, the apparatus comprising:

• a processor;
• and
• a non-transitory memory having stored thereon executable instructions, which when executed, cause the processor to perform:
• determining a quantization parameter for a processing unit of the image;
• and
• determining if a prediction mode included in header information is a first prediction mode,
• wherein if the header information indicates that the prediction mode is the first prediction mode, the processor further performs:
• modifying the determined quantization parameter using a quantization offset parameter for the first prediction mode;
• and
• performing a quantization process for the processing unit using the modified quantization parameter, and
• wherein if the header information indicates that the prediction mode is a second prediction mode which is different from the first prediction mode, the processor further performs:
• performing a quantization process for the processing unit without using the quantization offset parameter for the first prediction mode.

An apparatus for decoding a coded image, the apparatus comprising:

• a processor;
• and
• a non-transitory memory having stored thereon executable instructions, which when executed, cause the processor to perform:
• determining a quantization parameter for a processing unit of the coded image;
• and
• determining if a prediction mode included in header information is a first prediction mode,
• wherein if the header information indicates that the prediction mode is not the first prediction mode, the processor further performs:
• modifying the determined quantization parameter using a quantization offset parameter for the first prediction mode;
• and
• performing an inverse quantization process for the processing unit using the modified quantization parameter, and
• wherein if the header information indicates that the prediction mode is a second prediction mode which is different from the first prediction mode, the processor further performs:
• performing an inverse quantization process for the processing unit without using the quantization offset parameter for the first prediction mode.