Why are we seeing letter box in LCD TVs?

[ItsMe]

Hmm...Just now my father called me and told that he wants to purchase an LCD TV, and asked for suggestions. I told him the cheap alternative - flat screen CRT, but he seems to be biased towards LCD. I guess TV adds are brainwashing him nowadays.. Sorry for the off topic discussion... but I found it to be a coincidence, since I was asking admin about why he needs a CRT TV today morning

 

[Sushubh]

after using different models of LCDs over the last 2 years, i still feel most comfortable watching my 2 year old Philips 29 CRT.

 

[SVK]

well . . . for eg. i have an airtel HD box. it lets me choose which aspect ratio i want to view television. 16:9 or 4:3 etc . . if i select 4:3 then there are 2 huge vertical letterboxes on right and left sides and the picture resembles what it would appear as on a square crt. i use 16:9 and it is stretched to fit screen.

so the STB does have the ability to choose aspect ratios. the problem lies in the broadcast signal and the aspect ratio it is transmitted in.

to suggest that different signals should be broadcasted and an appropriate one could be selected by the STB sounds highly unfeasible (if possible at all). Consider the scarce spectrum resources while thinking of multiple broadcast signals and additional transponder cost which would eventually be passed on to consumers.
Yes channels can be broadcasted with Aspect Ratio information. The MPEG (I guess) has option to provide info about Aspect Ratio being broadcast for the channel, and STB can accordingly adjust its video output to 4:3 or 16:9. Another method of doing so is use of SCART (SCART - Wikipedia, the free encyclopedia) which has option for signalling on its pin (no. 8), but its not used in India, nor STB/TV/DVD player have SCART connector option.