[noggin]

 

Thanks fro the reply. What codec is used for the Freeview HD channels? Sorry for asking maybe a dumb question, but is it 1080i h264?   

I believe the majority of Freeview HD broadcasts are 1080i h264, however I seem to remember reading a while back that the BBC were switching between 1080i/50 and 1080p/25 depending on the program being broadcast.
Sorry I'm not up to spec on the subject any more than that.  

Almost correct. The encoders used for PSB3 - the main UK Freeview HD mux (which carries BBC One HD, BBC Two HD, CBBC HD, ITV HD, C4 HD and C5 HD) and which is encoded by the BBC (or their partners) - use advanced encoders that dynamically switch between 1080i25 and 1080p25 encoding on-the-fly (not programme by programme) based on whether they detect the source to be native i25 interlaced or native p25 progressive. I think this encoder switching can change GOP by GOP, but not within a GOP.

I don't know if the Arqiva-encoded COM7 and COM8 (which carry BBC News HD and CBeebies/BBC Four HD, along with other channels) use the same encoding.

When the BBC switched from permanent i25 encoding (with MBAFF) to on-the-fly i25/p25 encoder switching (to improve coding efficiency), some Sony HDTVs started glitching on the i/p changes... (Incidentally this is also why some Sony TVs report channels being 1080p25 rather than 1080i25)