I understand that my older PVR cannot receive picture for Mpeg4 broadcasts, which explains why I get sound but no picture on HIFIHD and radX, which are listed as Mpeg4 broadcasts. However Smithsonian channel is not listed as Mpeg4 but I get sound and no picture as with the Mpeg4 channels. Oasis, also not listed as Mpeg4, has both picture and sound, although I think that did not happen until some time after the free trial period began. Can anyone clarify which of these are Mpeg4 and which not and why I can get some of the four but not others? The information on the website does not seem to explain it.