On Saturday 15 May 2004 23:42, you wrote: > From: "Gavin Hamill" <[EMAIL PROTECTED]> > > > I'm not sure what DVB-SI is > > (is the one pertaining to CAMs and encryption?) > > No, DVB-SI is "DVB Service Information". Look at it this way: MPEG-2 > defines the _base_ of a digital television system, but leaves many things > open, e.g. how to transmit network-specific reception information, service > names, etc. > > Thus, DVB-SI is what "completes" MPEG-2 to a full digital television > system, DVB. ATSC is a different "completion" of MPEG-2 and uses different > data formats for service information. I think the main difference is that > DVB-SI uses the same table and descriptor format that MPEG-2 uses, while > ATSC uses fixed-size tables, which are easier to parse, but are not > consistent with the MPEG-2 base. > > > It's interesting to note that the reason we dropped from using QAM64 / > > FEC2_3 was to 'improve the picture quality' (reduce UNCs in fringe > > areas) but the lower available bitrate means each station is now > > transmitting a lower quality picture. Again, so much for progress... > > Oh, so there's no more QAM64 DVB-T in the UK? Hmm, I think it will _have > to_ return some day, because HDTV is very bandwidth hungry :-)
Only some channels are QAM-16. The "ITV" transponders are still QAM-64. My guess for HDTV is they're relying on the transition to all-digital thus freeing up the currentl analogue frequencies. http://www.dtg.org.uk/retailer/dtt_channels.htm -- Info: To unsubscribe send a mail to [EMAIL PROTECTED] with "unsubscribe linux-dvb" as subject.
