A method of transcoding an input video bit-stream having a first encoding profile having associated quantization factors including a user definable quantization matrix into an output video bit-stream having a second encoding profile having associated quantization factors including a hard-coded quantization matrix, said first encoding profile including motion estimation information, the method including the operations of: - extracting said motion estimation information from said input video bit-stream, and - passing said motion estimation information on to said output video bit-stream, thereby avoiding motion estimation in constructing said output bit-stream, the method includes the operations of: - extracting said quantization factors from said input video bit-stream, and - passing said quantization factors on to said second encoding producing said output video bit-stream, said quantization factors including information pertaining said user-definable quantization matrix that is used for selecting a quantizer translation for calculating a quantization parameter (Qp) for the second encoding profile from a quantization step (mquant) comprised in said quantization factors, characterized in that the calculation of the quantization parameter (Qp) including a correction of the quantization translation that includes the steps of: - extracting, for each block in said input video bit-stream, the corresponding DCT coefficients from said input video bit-stream; - calculating gradients on the DCT coefficients of each block; - said operation of passing said quantization factors on to said second encoding producing output video bit-stream including passing said DCT coefficients and gradients; - modifying the calculated quantization step on the basis of the value of one or more of said gradients, reducing the pre-calculated quantization step if one or more of said gradients is a flat gradient indicating the presence of a high frequency DCT coefficient. - extracting said motion estimation information from said input video bit-stream, and - passing said motion estimation information on to said output video bit-stream, thereby avoiding motion estimation in constructing said output bit-stream, - extracting said quantization factors from said input video bit-stream, and - passing said quantization factors on to said second encoding producing said output video bit-stream, said quantization factors including information pertaining said user-definable quantization matrix that is used for selecting a quantizer translation for calculating a quantization parameter (Qp) for the second encoding profile from a quantization step (mquant) comprised in said quantization factors, - extracting, for each block in said input video bit-stream, the corresponding DCT coefficients from said input video bit-stream; - calculating gradients on the DCT coefficients of each block; - said operation of passing said quantization factors on to said second encoding producing output video bit-stream including passing said DCT coefficients and gradients; - modifying the calculated quantization step on the basis of the value of one or more of said gradients, reducing the pre-calculated quantization step if one or more of said gradients is a flat gradient indicating the presence of a high frequency DCT coefficient.