to the pixel to pixel mapping used in tone mapping the block based bit depth scaling approach divides the picture into blocks of pixel and adopts identical scaling and offset values for pixels inside the block that is the video encoders determine a set of scaling factor and offset values for each block and the video decoders utilize the determined set of scaling factor and offset values with the decoded pixel of the low bit depth in the bl video to reconstruct the pixel of the high bit depth in the el video the block size may be aligned with the macro block size a 16 u00d7 16 pixel block size or a sub micro block size such as an eight by eight 16 u00d7 8 8 u00d7 16 8 u00d7 4 4 u00d7 8 or 4 u00d7 4 which are compatible with the current scalable video codec svc standard referring to fig5 for purposes of improving the coding efficiency an svc system 250 may be used in accordance with embodiments of the invention the svc system 250 has a similar design to the system 200 with similar reference numerals being used to denote similar components except that the svc system 250 includes content adaptive bit depth enhancers 50 a and 50 b each of which shares the design of the content adaptive bit enhancer 50 see fig2 in this regard as depicted in fig5 the bit depth enhancer 50 a is located between the inverse.