A method of forming a bitstream by an encoder apparatus comprising: a processor of the encoder apparatus receiving a projected video frame having a pixel area which includes a plurality of pixel regions, the plurality of pixel regions having pixels representing spherical video data projected onto a plurality of 2D projection surfaces of a 3D projection model, and the plurality of 2D projection surfaces being mapped to said plurality of pixel regions in a one-to-one manner; subsequently the processor generating a plurality of different candidate video frames on the basis of the projected video frame, each candidate video frame being generated by applying one or more pixel operations to pixels of said projected video frame, a pixel operation being defined as applying at least one of a shift, mirror and/or rotation operation to one or more groups of pixels, at least one of said one or more pixel operations being different each time one of said plurality of different candidate video frames is being generated, each of the one or more groups of pixels defining one of the plurality of pixel regions, and further defining one or more coding blocks; the processor applying a rate distortion analysis to each of the candidate video frames to determine a rate distortion cost for each of the candidate video frames; and, the processor selecting a candidate video frame from said plurality of candidate video frames on the basis of the rate distortion cost, the candidate video frame having the lowest rate distortion cost of said plurality of candidate video frames; and, generating an output bitstream on the basis of the selected candidate video frame, wherein the generating of the output bitstream includes: determining decoder information, the decoder information including information for enabling a decoder apparatus to reverse said one or more pixel operations applied to generate said selected candidate video frame; and, coding the selected candidate frame and the decoder information, in a sequence of bits, the coding including the use of an entropy coding algorithm, at least part of the decoder information being inserted as one or more SEI messages in the bitstream. a processor of the encoder apparatus receiving a projected video frame having a pixel area which includes a plurality of pixel regions, the plurality of pixel regions having pixels representing spherical video data projected onto a plurality of 2D projection surfaces of a 3D projection model, and the plurality of 2D projection surfaces being mapped to said plurality of pixel regions in a one-to-one manner; subsequently the processor generating a plurality of different candidate video frames on the basis of the projected video frame, each candidate video frame being generated by applying one or more pixel operations to pixels of said projected video frame, a pixel operation being defined as applying at least one of a shift, mirror and/or rotation operation to one or more groups of pixels, at least one of said one or more pixel operations being different each time one of said plurality of different candidate video frames is being generated, each of the one or more groups of pixels defining one of the plurality of pixel regions, and further defining one or more coding blocks; the processor applying a rate distortion analysis to each of the candidate video frames to determine a rate distortion cost for each of the candidate video frames; and, the processor selecting a candidate video frame from said plurality of candidate video frames on the basis of the rate distortion cost, the candidate video frame having the lowest rate distortion cost of said plurality of candidate video frames; and, generating an output bitstream on the basis of the selected candidate video frame, wherein the generating of the output bitstream includes: determining decoder information, the decoder information including information for enabling a decoder apparatus to reverse said one or more pixel operations applied to generate said selected candidate video frame; and, coding the selected candidate frame and the decoder information, in a sequence of bits, the coding including the use of an entropy coding algorithm, at least part of the decoder information being inserted as one or more SEI messages in the bitstream. determining decoder information, the decoder information including information for enabling a decoder apparatus to reverse said one or more pixel operations applied to generate said selected candidate video frame; and, coding the selected candidate frame and the decoder information, in a sequence of bits, the coding including the use of an entropy coding algorithm, at least part of the decoder information being inserted as one or more SEI messages in the bitstream.