DIRECTV and Dish Network have both announced plans to upgrade some of their transmissions to 1080p via MPEG4 and have compared that to "Blu-ray" format. However, the compression and data rates used raise the question of whether the picture really is "Blu-ray" quality, according to the New York Times on Thursday.

Until recently, satellite transmission rates limited the picture quality to 720p or 1080i. However, new compression algorithms, such as MPEG4 and others, have allowed the carriers to expand their signal to 1080p on PPV channels.

That has led to claims that some upcoming offerings "will be available in 1080p resolution -- same as Blu-ray Disc quality."

There’s a catch there. The vertical resolution and progressive scan (1080p) doesn’t guarantee the same picture quality as Blu-ray due to the additional compression used. [Blu-ray video is also compressed.]

For example, broadcast HDTV video has a bandwidth of about 17 Mbps. Video comes off a Blu-ray disc at about 30 Mbps. According to Pete Putnam, a TV engineer with ROAM consulting, the satellite companies are sending their HD signals at about 6 to 8 Mbps.

Customers have been able to notice the different compression rates used by cable and satellite. Sometimes, the extra compression reveals itself in a softer picture or even small digital blocks scattered around on the screen.

One of the advantages of having a Blu-ray player is not only the extra bandwidth for video but also for audio formats of much higher quality than the standard Dolby 5.1 used by satellite and cable for HD. Accordingly, the Bu-ray disc association is watching this new marketing terminology by the satcasters with interest.

"We’ll have to see what comparisons are made and what comes out of it," said Andy Parsons, head of the Blu-ray Disc Association.