I agree that the switching is annoying. It seems to happen a minute or so before they go to the studio in N.Y. for an update and coming in and out of commercials. Sometimes it also seems to happen randomly for no reason at all. My receiver has a momentary drop out when the switching occurs so I miss a syllable or word when it happens.
FOX and NBC seem to do it more seemlessly. ESPN never switches out of DD 5.1 so it's not an issue.
I wish CBS would refine this! :nono2:
CBS is actually following the Dolby concept; give the control of audio to the producer of the program. Hence, if a commercial is produced in stereo, it is aired in Stereo and if the program is in 5.1, that's what you are supposed to hear.
The affiliates are sent data that can control their local AC-3 encoding equipment. Some stations use it properly, others don't. For that reason it's hard to tell if the complaint is about your local CBS station, or the mixed stereo/5.1 system that CBS supports. When properly implemented, the CBS system is sound. (pun intended)
When you hear a difference between the level of a network commercial within a show and the level of the show, that's up to CBS, If you hear a difference between the level of a local commercial and the CBS program, that's the local station's responsibility.
The audio dropout when it switches modes is a configuration issue at your local affiliate. The data rate must be set to 384 kb/s for both 5.1 and stereo. You can do stereo at 192 kb/s, but switching from 192 to 384 causes the brief silent period that you are observing. Solving the problem is a configuration setting on their Dolby DP569 encoder.