Hi, All, I have a question about the scalability in MPEG4. If "ref_select_code" is 1. What are the reference Vops (backward + forward) for enhancement Vops in the following example? I B P B P B base | | | | | | ------------------------------------- enh | | | | | P B B B B Regards, Lei ---------------------------------- Lei Ming Tvia Inc. (408)982-8588 ext. 162