Varying picture quality between cable companies, “Theater” picture setting on Toshiba TV

Q:     I am hearing that a DirecTV HDTV signal is far superior to a HDTV signal from my cable company.  Is this true? My cable company is now offering HDTV through its digital service but I understand that this is sometimes a very soft signal. Garbage in and garbage out really has never reached such levels because I know that a bad signal on a great HDTV is only magnified like never before. Can you help, what do you know about this?

-Mike Freer, Columbus, Ohio

A:   The quality of the HDTV signal transmitted over cable systems is wholly dependent on the particular cable company.   The quality of the signal will vary depending on the capacity of their system and their philosophy when it comes to image quality and signal transmission.  

Cable companies have capacity limitations over their cable systems, and an HDTV signal transmitted at full quality takes up a lot of available space.   There have been reports that some cable companies offering “HDTV” service are not transmitting HDTV channels at full quality in order to conserve this space for additional pay-per-view offerings, video-on-demand and other similar channels and services.

Digital television signals are composed of millions of digital bits transmitted every second.   The more bits, the better the picture.   To be considered true HDTV, the signal must be at least 19.4 million bits per second.     I recently spoke with a technician installing new capabilities for one of the country’s largest cable providers.   I asked him what bitrate they are using for HDTV, and he told me it was 10 million bits per second.   While such a picture may look good compared to a regular digital channel, it is still well below what a full-quality HDTV signal should be.

A few months ago I received a question similar to yours regarding HDTV via cable.   I contacted three cable companies and asked the bitrate being used for their “HDTV”.   All three companies said they would get back to me.   None of them ever did.

In terms of personal experience, I recently visited a friend who is getting HDTV via cable.   She has a Mitsubishi HDTV similar to the one I own.   Watching the PBS HDTV demo channel, it did not have nearly the clarity, vibrancy, or visual impact I experience with my Mitsubishi HDTV receiving the same channel via an antenna.   While she thought her picture was very good, I imagine she will be disappointed with it when she sees the same channel on my television running at full quality.

Again, cable companies differ.   If image quality is of prime concern to you, I would recommend you stick with HDTV via satellite or via an antenna over-the-air as it is a safe bet.   If would like to give HDTV via cable a try, call and ask a technician what bitrate they are using for HDTV transmissions.   If their HDTV is being broadcast at 19 million bits per second (Mb/s) or greater, you should have picture quality that rivals satellite and over-the-air HDTV transmissions.

Q:     My Toshiba TV has a setting called “Theater” in the picture controls.   I have tried it and it just seems to make the picture darker.   What is it there for?

-Katherine Shaw, Cranberry, PA

A:   On most televisions, including your Toshiba, the “Theater” setting is designed to be used it total darkness, just like the movie theater experience.   When you activate this setting, it makes subtle adjustments to the picture that imitates the depth and look of a movie screen showing projected film. Try it in a totally dark room next time with your favorite DVD.

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