Video encoding method and system

A Method for encoding a video stream comprising:

• determining a level of relevance for areas in an image frame to be included in the video stream,
• determining a block size value for coding blocks in the image frame, the block size value is depending on the level of relevance determined for the area including each coding block, respectively, wherein higher level of relevance relates to smaller block sizes than lower level of relevance,
• encoding the image frame using coding block sizes based on the determined block size values for each of the coding blocks wherein determining the level of relevance for areas in an image frame to be included in the video stream comprises:
• calculating a statistical measure for groups of neighboring pixels, the statistical measure for each group of neighboring pixels being referred to as a group value for the specific group of neighboring pixels, calculating differences between group values, comparing said differences to a predetermined threshold value, if the difference is equal to or above the threshold value, increasing the level of relevance of an area including the group, and if said differences is below said threshold value, decreasing the level of relevance of an area including the group, wherein the statistical measure is at least one from the group consisting of a sum, a mean, a median, an interquartile range, a standard deviation, a variance, a skewness and a kurtosis, of pixel data in the group of pixels.