All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is permissible to change a television channel while the Azaan is being broadcasted on it, but it is better to keep it until the Azaan is over in order for the listener to repeat its words as urged by the Sunnah.
As for performing prayer after the Azaan is called on television: if the person lives in the same region where the televised Azaan is called or in one that shares the same time of Azaan, then such a prayer is permissible. This is so because the Azaan is a proclamation of the beginning of the due time of prayer made by a Muazzin who is in charge of observing prayer timings, and with his calling of the Azaan both prayer and breaking a fast become permissible, even if the Azaan of the mosque is not yet called, since it may be late for some reason.
On the other hand, if the person lives in a city that is far from the one in which the televised azan is called, and the time of prayer has not yet begun in his city; then it is impermissible to perform prayer if its due time has not yet begun in the city where he lives.
We also caution that it is impermissible for a man to pray alone if he is physically able to offer the prayer in congregation.
Allaah Knows best.