Patent ID: 6201844
Filing Date: 2001-03-13
Classification: H04N

Abstract:
A method of transcoding a data stream (DS) comprising a time multiplex of coded data (D) and control data (C), the method comprising the step of transcoding (T) the coded data (D) so as to obtain transcoded data (DT) which differs in size from the coded data (D),adapting (A) the control data (C) for the transcoded data (DT) so as to obtain adapted control data (CA) which is substantially equal in size to the control data (C);writing the transcoded data (DT) and the adapted control data (CA) in a transcoder output buffer (TOB); andreading the transcoded data (DT) and the adapted control data (CA) from the transcoder output buffer (TOB) so as to obtain a transcoded data stream (DST),wherein the data stream (DS) comprises control codes (CC), a control code (CC) defining a decoder input buffer delay (.DELTA.Tdib) for a coded data portion (P) associated therewith, the input buffer delay (.DELTA.Tdib) being the difference between an instant (Twd1) when the coded data portion (P) is written into a decoder input buffer (DIB1) and an instant (Trd1) when the coded data portion (P) is to be read from the decoder input buffer (DIB1),calculating a transcoder output buffer delay (.DELTA.Ttob) being the difference between an instant (Twt) when a transcoded data portion (PT) obtained by transcoding the coded data portion (P) is written into the transcoder output buffer (TOB), and an instance (Trt) when the transcoded data portion (PT) is read from transcoder output buffer (TOB);calculating a new decoder input buffer delay (.DELTA.Tdibnew) which is substantially equal to the sum of the decoder input buffer delay (.DELTA.Tdib) and a transcoding delay (.DELTA.Ttrans) minus the transcoder output buffer delay (.DELTA.Ttob); andproviding, for the transcoded data portion (PT), an adapted control code (CCA) which defines the new decoder input buffer delay (.DELTA.Tdibnew).