METHOD AND ARRANGEMENT FOR TRANSCODING A VIDEO BITSTREAM

摘要

The present inventon relates to a method and a transcoder arrangement of transcoding a bitstream representing an original video source from an input format to an output format. The method comprises the steps of receiving (S10) the bitstream with the input video format, wherein the input video format is a high fidelity format; and receiving (S20) side information related to said video bitstream. Said side information comprising at least: a video bitstream representing the original video source with a low fidelity input video format, coding parameters optimized based on knowledge of the original video source; transform coefficients, indicative of a residual between the original video source and a decoded version of the high fidelity format. The method further comprises decoding (S40) said received side information to generate transcoding guiding information, estimating (S50) a representation of said bitstream with a low fidelity output format based on the received bit stream and the generated transcoding guiding information, adding (S60) the transform coefficients of the side information to transform coefficients generated from the estimated representation of said bitstream with the low fidelity output format to improve the estimated representation of said bitstream with the low fidelity output format and encoding (S50) the improved estimated representation of said bitstream with the low fidelity output format.