I tried to learn german sometime ago and I was counting on german TV for immmersion. I have learned many words and phrases in other languages this way, but in Germany I just quit trying and watched satellite TV instead.There was no way to watch TV if you didn't speak at least some german.
I find original programs with subtitles are much more helpful for retaining phrases and idioms. Some TV channels use subtitles in all programs, for the hearing impaired. This is also helpful, because the language learner can read and listen at the same time.
Also, I find programs in their original language are much better to watch anyway. A film or TV drama consists of many parts, some of which are puns, diction, word order and matching sounds with face expressions. Dubbing, no matter how good, takes half of the fun away.