A method for coding an input pixel block containing multi-directional image content, comprising: for a spherical domain transform based on a distance from the center of a spherical projection, a vertical direction and a horizontal direction within a reference picture having an equirectangular format, transforming content of the reference picture within a search window that stretches reference frame content of the input based on a vertical displacement in order to counter-act imaging distortion, wherein the content of the reference picture is transformed based on the vertical displacement between the location of the input pixel block and a location of the content within the search window and based on a location of the input pixel block, wherein for a row of pixel blocks including the input pixel block, the transformed content of the reference picture is used for prediction searches of the other pixel blocks in the row; performing a prediction search along the horizontal direction and within the transformed content of the reference picture to estimate coding distortion for each candidate motion vector along the horizontal direction; transforming content of the reference picture within the search window that stretches reference frame content of the input based on a horizontal displacement in order to counter-act imaging distortion, wherein the content of the reference picture is transformed based on the horizontal displacement between the location of the input pixel block and the location of the content within the search window and based on the location of the input pixel block, wherein for a column of pixel blocks including the input pixel block, the transformed content of the reference picture is used for prediction searches of the other pixel blocks in the column; performing a prediction search along the vertical direction and within the transformed content of the reference picture to estimate coding distortion for each candidate motion vector along the vertical direction; once estimates have been obtained for all candidate motion vectors selecting the motion vector that minimizes overall coding cost, coding the input pixel block differentially with respect to the transformed content of the reference picture according to the selected motion vector. transforming content of the reference picture within a search window that stretches reference frame content of the input based on a vertical displacement in order to counter-act imaging distortion, wherein the content of the reference picture is transformed based on the vertical displacement between the location of the input pixel block and a location of the content within the search window and based on a location of the input pixel block, wherein for a row of pixel blocks including the input pixel block, the transformed content of the reference picture is used for prediction searches of the other pixel blocks in the row; performing a prediction search along the horizontal direction and within the transformed content of the reference picture to estimate coding distortion for each candidate motion vector along the horizontal direction; transforming content of the reference picture within the search window that stretches reference frame content of the input based on a horizontal displacement in order to counter-act imaging distortion, wherein the content of the reference picture is transformed based on the horizontal displacement between the location of the input pixel block and the location of the content within the search window and based on the location of the input pixel block, wherein for a column of pixel blocks including the input pixel block, the transformed content of the reference picture is used for prediction searches of the other pixel blocks in the column; performing a prediction search along the vertical direction and within the transformed content of the reference picture to estimate coding distortion for each candidate motion vector along the vertical direction; once estimates have been obtained for all candidate motion vectors selecting the motion vector that minimizes overall coding cost, coding the input pixel block differentially with respect to the transformed content of the reference picture according to the selected motion vector.