A decoder for decoding an input encoded bitstream with incorporated enhancement control parameters, encoded with an encoder for encoding a video bitstream to produce the encoded bitstream, the decoder comprising: - a decoder for decoding the input signal and separating the enhancement control parameters from the decoded signal; - an enhancement unit (604,606) for enhancing the decoded signal based on said enhancement control parameters, and the encoder comprising: - a base encoder for encoding the input video bitstream in an encoded base stream, and for providing a decoded base stream; - an enhancement unit for enhancing the decoded base stream based on enhancement control parameters; - a first picture content parameter unit for extracting an enhanced picture content parameter value or values for at least one picture content parameter from the enhanced base stream; - a second picture content parameter unit for extracting an input picture content parameter value or values for said at least one picture content parameter from the input video bitstream; - comparison means (226, 228) for comparing the enhanced picture content parameters with the input picture content parameters; characterised in that the encoder further comprises: - a control unit for receiving an output from the comparison means and for calculating, from a result of said comparing, said enhancement control parameters which will minimize the difference between the input picture content parameter value or values and the enhanced picture content parameter value or values; - means (214, 240) for forming the output bitstream, incorporating the encoded base stream and the calculated enhancement control parameters into the encoded output bitstream wherein the picture content parameters are from the group comprising difference between maximum and minimum value of a group of pixels, edge steepness value at center of edges. - a decoder for decoding the input signal and separating the enhancement control parameters from the decoded signal; - an enhancement unit (604,606) for enhancing the decoded signal based on said enhancement control parameters, - a base encoder for encoding the input video bitstream in an encoded base stream, and for providing a decoded base stream; - an enhancement unit for enhancing the decoded base stream based on enhancement control parameters; - a first picture content parameter unit for extracting an enhanced picture content parameter value or values for at least one picture content parameter from the enhanced base stream; - a second picture content parameter unit for extracting an input picture content parameter value or values for said at least one picture content parameter from the input video bitstream; - comparison means (226, 228) for comparing the enhanced picture content parameters with the input picture content parameters; - a control unit for receiving an output from the comparison means and for calculating, from a result of said comparing, said enhancement control parameters which will minimize the difference between the input picture content parameter value or values and the enhanced picture content parameter value or values; - means (214, 240) for forming the output bitstream, incorporating the encoded base stream and the calculated enhancement control parameters into the encoded output bitstream