Method and device for transcoding images

A device for transcoding digital images, comprising:

• a means for decoding of at least portions of a first image coded according to a first method for obtaining first coefficients of a luminance component and chrominance components of the first image coded according to the first method;
• a means for combined inverse quantization according to the first method and quantization according to a second method of the first coefficients of the chrominance components of the first image coded according to the first method, by means of a chrominance matrix of the first method for inverse quantization according to the first method and a luminance quantization matrix of the first method for quantization according to the second method, for obtaining second coefficients of chrominance components of at least portions of a second image according to the second method having the same chroma format as the first image coded according to the first method, said means being operatively connected to said means for decoding;
• and a means for coding of the first coefficients of the luminance component of the at least portions of the first image coded according to the first method and of the second coefficients of the chrominance components of at least portions of the second image according to the second method, for obtaining at least portions of the second image decodable according to the second method, said means being operatively connected to said means for combined inverse quantization and quantization and to said means for decoding.