Data encoding and decoding apparatus, method and storage medium

A video data decoding method comprising:

• detecting by circuitry a control flag associated with at least a part of an encoded image for decoding;
• in a lossless mode of operation, enabling sample-based angular intra-prediction but disabling edge filtering of prediction samples in response to the control flag being enabled;
• in the lossless mode of operation, disabling sample-based angular intra prediction but enabling edge filtering of prediction samples in response to the control flag being disabled;
• in a lossy mode of operation, enabling residual differential pulse code modulation coding and enabling edge filtering of prediction samples in response to the control flag being enabled;
• and in the lossy mode of operation, disabling residual differential pulse code modulation coding but enabling edge filtering of prediction samples in response to the control flag being disabled.

A video data encoding method comprising:

• generating by circuitry a control flag associated with at least a part of an encoded image, by:
• setting the control flag to be enabled in a lossless mode of operation to enable sample-based angular intra-prediction but to disable edge filtering of prediction samples;
• setting the control flag to not be enabled in the lossless mode of operation to disable sample-based angular intra prediction but to enabled edge filtering of prediction samples;
• setting the control flag to be enabled in a lossy mode of operation to enable residual differential pulse code modulation coding and to enable edge filtering of prediction samples;
• and setting the control flag to not be enabled in the lossy mode of operation to disable residual differential pulse code modulation coding but to enable edge filtering of prediction samples in response to the second control flag state.