Context-adaptive pixel based prediction for intra frame encoding
Intra prediction is one effective method to remove the spatial redundancies in intra frame coding. Better intra prediction will result in the residual with less energy, which will decrease the number of bits needed to reconstruct the signal at decoder. To improve the accuracy of intra prediction, a context-adaptive pixel based prediction (CAPBP) algorithm is proposed in this paper. For each pixel within the target block to be encoded, the prediction is calculated as the linear weighted summation of the reconstructed pixels within the left column and the above row. Based on the assumption that pixels having the same coordinates within one block own the same prediction weights, we calculate the corresponding weights for each pixel within the target block by the least square method. The same processing is also performed at decoder; hence the prediction weights do not need to be sent to the decoder. Experimental results verify that the proposed algorithm is able to improve the efficiency of intra frame coding up to 0.5dB.