Intra prediction method based on the linear relationship between the channels for YUV 4∶2∶0 intra coding
In general, the transformation from RGB to YUV color space reduces the correlation between the channels. But some sources in the YUV space still have strong inter-channel correlation, which can be modeled as a linear function. Based on this linear model, we propose a new intra chrominance prediction method for color image compression in YUV 4∶2∶0 color space. A block of chrominance pixels to be encoded is predicted from the reconstructed luminance signal using the proposed prediction scheme and the residual is encoded based on the H.264/AVC. Also, an implicit prediction method that can obviate the transmission of side information is proposed. The experimental results show that there are about 0.35∼1.0dB gains for the luminance (Y) channel, and 0.5∼3.0dB gains for the chrominance (Cb or Cr) channels at the medium to high bit-rates. The proposed method also shows some gains at the low bit-rates.