SetSequenceProgressProc allows you to set a progress procedure on a Compression or Decompression Sequence, just as in the past you could have a progress procedure when compressing or decompressing a still image.
pascal OSErr SetSequenceProgressProc(ImageSequence seqID, ProgressProcRecord *progressProc)
seqID Sequence identifier.
progressProc Pointer to a record containing information about the application's progress proc.