Method and data carrier for transmitting a data stream

A method for transmitting a data stream between a mobile data carrier and a playback device for the transmitted data, the method comprising:

• transmitting, via a first transmission channel between the mobile data carrier and the playback device, which is set up by an electromagnetic field emitted by the playback device and electromagnetic induction in the mobile data carrier, authentication data for setting up a second transmission channel from the mobile data carrier to the playback device, and
• following verification of the authentication data, setting up the second transmission channel between the mobile data carrier and the playback device,
• wherein the data stream from the mobile data carrier to the playback device is transmitted via the second transmission channel by a radio signal from a transmitting antenna of the mobile data carrier,
• wherein power is supplied to the transmitting antenna of the mobile data carrier via the first transmission channel, and
• wherein the second transmission channel is maintained only as long as the first transmission channel, whose maintenance depends on a spatial distance between the mobile data carrier and the playback device, is maintained.