Nick -
you are posting incorrect information - at least about Discovery Channel delivery specs.
Below is partial documentation about Discovery HD delivery specs.
This comes from the following link -
http://www.discoverychannel.ca/_includes/disclaimer/producers_guide/
Bob Zelin
BROADCAST MASTERS
Sony HD Cam 1080i / 59.94, Stereo audio on channels 1 & 2, Dolby 5.1 mix (when available) expressed as Dolby E on channels 3 & 4.
Where facilities exist, the HD master must be accompanied by a closed captioned Betacam SX standard definition down converted dub. This standard definition dub shall contain a 16:9 letterboxed image obtained from the HD master. The program content shall be exactly the same on both versions of the master and the times codes shall match exactly. Audio shall also match for any Lt/Rt or Lo/Ro content but no Dolby E is necessary. Closed captioning shall be on line 21.
Discovery HD requires programs to be mastered in the 1080i 59.54 signal standard. Programs may be acquired in the 720P 59.94 signal standard and mastered in 1080i 59.94 for delivery only with prior approval. Programs may be acquired and delivered in 1080 psf 23.98 or 25, or 1080i 50 only with prior permission from Discovery HD.
