Method and device for the synchronised restitution of data flows

A method for reproducing data streams or data packets transmitted via at least one network using at least two reproduction units which are at least indirectly linked to the network, the method comprising:

• synchronizing reproduction using the at least two reproduction units,
• either by virtue of one of the reproduction units, as master, prescribing an internal clock of the master as reference and the other reproduction units, as slaves, aligning internal clocks of slaves with that of the master via the network or carrying a copy of the master clock and reproducing data streams or data packets on the basis of this aligned clock,
• or by virtue of the internal clock of an external unit which is likewise available on the network being used as the master and all reproduction units, as slaves, aligning their internal clock with that of the master via the network and reproducing data streams or data packets on the basis of this aligned clock,
• wherein the data streams or data packets are used to send at least one command to the reproduction units together with an associated execution time, the execution time being set to a time between the transfer of the command to the network and the execution time which is greater than a longest network delay time between the master and the slaves.

A method for reproducing data streams or data packets transmitted via at least one network using at least two reproduction units which are at least indirectly linked to the network, the method comprising:

• synchronizing reproduction using the at least two reproduction units,
• either by virtue of one of the reproduction units, as master, prescribing an internal clock of the master as a reference and the other reproduction units, as slaves, aligning internal clock of the slaves with that of the master via network or carrying a copy of the master clock and reproducing data streams or data packets on the basis of this aligned clock,
• or by virtue of the internal clock of an external unit, which is likewise available on the network being used as the master and all reproduction units, as slaves, aligning their internal clock with that of the master via the network and reproducing data stream or data packets on the basis of this aligned clock, wherein
• a reproduction unit that has been switched in transfers the data streams or data packets received from the network directly to a codec,
• the codec rejects the supplied data by muting until the codec detects a first valid frame, the codec is stopped when the codec detects the first valid frame and the current byte is noted, and
• the codec is the reproduction unit processes the data stream or the data packets again and is switched to reproduction when this current byte is played on the master, after the codec is stopped and the current byte is noted.

A non-transitory computer readable medium containing program instructions for execution on a computer which when executed by a processor causes the computer to perform the method comprising:

• transmitting data packets between the at least two reproduction units asynchronously;
• buffering data packets in the at least two reproduction units dynamically so as to be matched to the circumstances of the network;
• synchronizing reproduction using the at least two reproduction units, wherein the reproduction units are synchronized in a range below 100 ms,
• either by virtue of one of the reproduction units, as a master, prescribing its internal clock as a reference and at least one other reproduction unit, as a slave, aligning its internal clock with that of the master via the network or carrying a copy of the master clock and reproducing data streams or data packets based on this aligned clock,
• or by virtue of the internal clock of an external unit available on the network being used as the master and all reproduction units, as slaves, aligning their internal clocks with that of the master via the network and reproducing data streams or data packets based on this aligned clock,
• wherein at least some of the data streams or data packets are temporarily buffered in the reproduction units before reproduction, with audio files involving buffering in a range of approximately 1to 5 sec;
• and
• aligning the clock on each slave before reproduction for the first time and updating the clock periodically during the reproduction, the periodic update being performed on the slave for systematically matching the speed of operation of the internal clock in the slave to that of the master in order to compensate for differences in the internal propagation-time characteristics of the master and the slave,
• wherein the internal clock in the slave is aligned by virtue of the internal clock in the master being requested by the slave, a plurality of times, and by virtue of at least one data packet, that may be identical to the packets for requesting the time on the master, being transmitted from the slave to the master and being sent back, and the internal clock in the slave being brought into line with the clock in the master on the basis of a mean propagation time, calculated as a mean taking into account handling times in the units, for data packets between the master and the slave.

A reproduction unit configured to reproduce data streams or data packets via an output unit transmitted via at least one network, in which data packets are transmitted asynchronously, using at least two reproduction units which are at least indirectly linked to the network via a network interface, comprising:

• The network interface configured to indirectly link the reproduction unit to at least one additional reproduction unit over the network;
• A central computer unit configured to automatically integrate the reproduction unit into the network, and including a memory storing a permanently programmed data processing program that is activated automatically after a power supply is turned on, the central computer unit being configured to synchronize reproduction of the data stream or data packets with the at least one additional reproduction unit, the reproduction time difference between the reproduction unit and the at least one additional reproduction unit being 100 ms, either
• by virtue of one of the reproduction units, as a master, prescribing an internal clock of the master as a reference and at least one other reproduction unit as a slave, aligning an internal clock of the slave with that of the master via the network or carrying a copy of the master clock, and reproducing the data streams or data packets based on this aligned clock,
• or by virtue of the internal clock of an external unit available on the network being used as the master and all reproduction units, as slaves, aligning their internal clocks with that of the master via the network and reproducing the data streams or data packets based on this aligned clock;
• and
• the output unit to at least indirectly output the data streams or data packets, wherein
• at least some of the data streams or data packets are temporarily buffered in the reproduction units before reproduction, with audio files involving buffering in the range of approximately 1to 5sec, the buffering being performed dynamically so as to be matched to the circumstances of the network,
• the clock on each slave is aligned before reproduction for the first time and is updated periodically during the reproduction, the periodic update being used on the slave for systematically matching the speed of operation of the internal clock in the slave to that of the master in order to compensate for differences in the internal propagation-time characteristics of the master and the slave, and
• the internal clock in the slave is aligned by virtue of the internal clock in the master being requested by the slave, a plurality of times, and by virtue of at least one data packet, that may be identical to the packets for requesting the time on the master, being transmitted from the slave to the master and being sent back, and the internal clock in the slave being brought into line with the clock in the master on the basis of a mean propagation time, calculated as a mean taking into account handling times in the units, for data packets between the master and the slave.