| 摘要 |
A method and a device for transcoding digital images is disclosed. At least portions of a first image coded according to a first method is decoded for obtaining first coefficients of a luminance component and chrominance components of the first image. Furthermore, the first coefficients of the chrominance components of the first image are subjected to a combined inverse quantization according to the first method and quantization according to a second method. The combined inverse quantization and quantization uses a chrominance quantization 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 for chrominance components of at least portions of a second image according to a second method having the same chroma format as the JPEG image. Finally, the first coefficients of the luminance component of the at least portions of the first image and the second coefficientsof the chrominance components of the at least portions of the second image are coded for obtaining at least portions of the second image decodable according to the second method. |
