Advanced video coding intra prediction scheme
A system and method are disclosed for efficiently determining a prediction block for a current block of interest in a video signal encoding protocol. In a preferred embodiment, this is achieved by determining whether there is a correlation between the intra 4×4 predictions and the 16×16 prediction modes. If the correlation to the 16×16 prediction modes is lower than a predetermined threshold value, then the additional prediction blocks using 16×16 intra luma prediction are not calculated. If the correlation to the 16×16 prediction modes is higher than the predetermined threshold value, then the additional prediction blocks are calculated using 16×16 intra luma prediction. A cost function may then be used to determine the predicted bit cost of each prediction block, and the prediction block with the lowest cost may be selected as the prediction block for the current block of interest.
1 . A method for determining a prediction block for a current block of interest, the method comprising the steps of:
determining the correlation between 4×4 intra luma prediction directions; and
depending on the determined correlation, either calculating additional prediction blocks using 16×16 intra luma prediction or skipping the 16×16 intra luma prediction calculations.
2 . The method of claim 1 wherein the additional prediction blocks are calculated using 16×16 intra luma prediction if the correlation between 4×4 intra luma prediction directions is high.
3 . The method of claim 1 wherein the correlation is high if it is larger than a predetermined threshold value.
4 . The method of claim 1 wherein the additional prediction blocks using 16×16 intra luma prediction are not calculated if the correlation between 4×4 intra luma prediction directions is low.
5 . The method of claim 4 wherein the correlation is low if it is smaller than a predetermined threshold value.
6 . The method of claim 1 further comprising the step of:
using a cost function to determining the predicted bit cost of each prediction block.
7 . The method of claim 6 further comprising the steps of
determining the prediction block with the lowest cost; and
selecting the prediction block with the lowest cost.
8 . A method for predicting an intra-code block for a current block of interest in a video signal encoding protocol, the method comprising the steps of:
determining the intra 4×4 predictions for the current block of interest; and
determining a correlation between the intra 4×4 predictions to the 16×16 prediction modes.
9 . The method of claim 8 further comprising the step of:
if there is a low correlation between the intra 4×4 predictions to the 16×16 prediction modes, then the 16×16 intra luma predictions for the current block of interest are not calculated.
10 . The method of claim 9 further comprising the steps of:
calculating the cost of each 4×4 prediction block; and
selecting the 4×4 prediction block with the lowest cost as the prediction block for the current block of interest.
11 . The method of claim 9 further comprising the steps of:
if there is a high correlation between the intra 4×4 predictions to the 16×16 prediction modes, then the 16×16 intra luma predictions for the current block of interest are calculated.
12 . The method of claim 11 further comprising the steps of:
calculating the cost for each 4×4 prediction block;
calculating the cost for each 16×16 prediction block; and
selecting either the 4×4 or 16×16 prediction block with the lowest cost as the prediction block for the current block of interest.
13 . A system for determining a prediction block for a current block of interest, the system comprising:
a correlation detector for detecting the correlation between 4×4 intra luma prediction directions; and
a 16×16 intra luma prediction determinator for calculating additional prediction blocks using 16×16 intra luma prediction;
wherein the additional prediction blocks using 16×16 intra luma prediction are calculated only if the correlation between the 4×4 intra luma directions is high and where the additional prediction blocks using 16×16 intra luma prediction are not calculated if the correlation between the 4×4 intra luma directions is low.
14 . The system of claim 13 wherein the correlation between 4×4 intra luma prediction blocks is high if the correlation is larger than a predetermined 16×16 Intra Luma Prediction Threshold.
15 . The system of claim 13 wherein the correlation between 4×4 intra luma prediction blocks is low if the correlation is smaller than a predetermined 16×16 Intra Luma Prediction Threshold.
16 . The system of claim 13 further comprising:
a coding complexity analyzer for determining the cost function for a given prediction block.
17 . The system of claim 16 wherein the coding complexity analyzer determines the predicted bit cost for a given prediction block.
18 . The system of claim 16 wherein the prediction block with the lowest cost function is selected as the prediction block for coding the current block of interest.