A method of generating a picture region, the method comprising: providing a first layer comprising a plurality of first layer pictures having a first quality level; wherein the first quality level comprises a first dynamic range; providing a second layer comprising a plurality of second layer pictures having a second quality level that is higher than the first quality level; wherein the second quality level comprises a second dynamic range higher than the first dynamic range; performing a first mode of picture region generation comprising inverse mapping from the first dynamic range to the second dynamic range a region of a picture from the first layer to generate a first intermediate picture region; performing a second mode of picture region generation comprising utilizing a second layer temporal signal from one or more previously decoded pictures in the second layer to generate a second intermediate picture region, wherein the second layer temporal signal comprises one or more pixels from the one or more previously decoded pictures in the second layer, wherein the first intermediate picture region and the second intermediate picture region correspond to the picture region to be generated; and selecting, as the picture region to be generated, one picture region from among the first intermediate picture region and the second intermediate picture region based on a metric; characterised in that the selecting comprises: determining one or more ranges, wherein each range is bounded by a pair of threshold pixel values; determining whether or not a mean of the region of the picture from the first layer is within one of the determined ranges; and if the mean of the region of the picture from the first layer is within one of the determined ranges: selecting the first intermediate picture region as the picture region to be generated; and if the mean of the region of the picture from the first layer is not within one of the determined ranges: selecting the second intermediate picture region as the picture region to be generated; wherein the determining of whether or not a mean of the region of the picture from the first layer is within one of the determined ranges comprises: computing a mean of the pixel values in the region of the picture from the first layer; and if the computed mean is within one of the pairs of threshold pixel values: determining that the region of the picture from the first layer is within one of the determined ranges. providing a first layer comprising a plurality of first layer pictures having a first quality level; wherein the first quality level comprises a first dynamic range; providing a second layer comprising a plurality of second layer pictures having a second quality level that is higher than the first quality level; wherein the second quality level comprises a second dynamic range higher than the first dynamic range; performing a first mode of picture region generation comprising inverse mapping from the first dynamic range to the second dynamic range a region of a picture from the first layer to generate a first intermediate picture region; performing a second mode of picture region generation comprising utilizing a second layer temporal signal from one or more previously decoded pictures in the second layer to generate a second intermediate picture region, wherein the second layer temporal signal comprises one or more pixels from the one or more previously decoded pictures in the second layer, wherein the first intermediate picture region and the second intermediate picture region correspond to the picture region to be generated; and selecting, as the picture region to be generated, one picture region from among the first intermediate picture region and the second intermediate picture region based on a metric; characterised in that the selecting comprises: determining one or more ranges, wherein each range is bounded by a pair of threshold pixel values; determining whether or not a mean of the region of the picture from the first layer is within one of the determined ranges; and if the mean of the region of the picture from the first layer is within one of the determined ranges: selecting the first intermediate picture region as the picture region to be generated; and if the mean of the region of the picture from the first layer is not within one of the determined ranges: selecting the second intermediate picture region as the picture region to be generated; wherein the determining of whether or not a mean of the region of the picture from the first layer is within one of the determined ranges comprises: computing a mean of the pixel values in the region of the picture from the first layer; and if the computed mean is within one of the pairs of threshold pixel values: determining that the region of the picture from the first layer is within one of the determined ranges.