The History Channel management is still brain-dead. Here's a response a newspaper columnist got recently (the column is dated today in fact):
TV Q&A with Rob Owen
"The History Channel HD feed is a simulcast of the network's standard definition east coast feed," explained a network spokeswoman. "Since the beginning of last year, all of our new programming is shot in HD, and as we move forward you will continue to see more and more HD programming. Please note that the required HD delivery format for all The History Channel programs is 1080p, which we adhere to. We still have some series and specials on the network that were produced in standard definition and in order to program the full screen we must "stretch" the image. We understand this is not the perfect solution, and apologize for the quality. Also, as you can imagine, original source material, such as archival footage that is integral to many of our shows, may have to be modified."