This ten minute video is obviously about Beethoven being deaf when he conducted his opera. I don't know anything else about it except that he indeed did go deaf. The video seems to be from a movie but I don't know that or any other facts about the video or if the video was based on a real incident or not.
He was not always deaf but he started going deaf around his late 20s and in a few years he was completely deaf but continued to compose by feeling the vibrations of his instrument.
Beethoven wasn't actually stone deaf as some would have you believe, however his hearing was seriously impaired. Here is one of the things that was written about his problem by him.
"It is curious that in conversation there are people who do not notice my condition at all; since I have generally been absentminded, they account for it in that way. Often I can scarily hear someone speaking softly, the tones yes, but not the words. However, as soon as anyone shouts it becomes intolerable"
Beethoven began to suffer from a very severe form of "tinnitus" (ringing in the ears) around the year 1796. He hearing gradually deteriorated until, it is believed, he lost nearly 100 percent of his hearing. It has been written that at the premier of his ninth symphony, he had to be turned around to see the tumultuous applause by the audience. Many people believe that he died of lead poisoning. The lead came from his drinking cup and not to mention they put lead in wine sometimes. All this was found out when a sample of his hair was analyzed in a lab just a few years ago.
He first noticed signs of deafness in his late 20s and he eventually went profoundly deaf. All the music of his late period was composed when he was totally deaf.