What is “restamping”?
Imagine a server with many bitstream files on it, perhaps commercials, and each one begins with a PCR value of zero. Now we splice one after the other. At each splice the PCR suddenly resets to zero! There are two options in this case. One is to declare a timing discontinuity by setting the discontinuity_indicator flag to ‘1’ in the IPP after the splice. This bit tells decoders to jam their PCR PLL counters with the next PCR value rather than trying to slew the VCO to catch up. MPEG compliance requires that decoders perform well through timing discontinuities. Another solution is for the splicing device to change all the timing values in the new stream (PCRs, PTSs, and DTSs) to correct for the offset induced by the splice. This process, called “restamping”, eliminates the timing discontinuity (although it does not compensate for a change in clock rate) . It is more complex than just setting the discontinuity_indicator at the splice point, and it is not possible for encrypted streams si
