Method of synchronizing playback of digital content between plurality of connected devices and device using the same

1. A method of synchronizing playback of a digital content between connected devices, the method comprising:

receiving a playback delay time list or a playback sync timestamp from a master device during a playback duty cycle;

calculating a playback delay time correction amount by referring to the playback delay time list in order to synchronize playback between a plurality of connected devices including the master device;

correcting a playback sync timestamp used in the playback synchronization according to the playback delay time correction amount; and

playing a digital content according to the corrected playback sync timestamp.

2. The method of claim 1 , further comprising:

transmitting, by the connected device, a playback delay time corrected during the playback duty cycle to the master device.

3. The method of claim 1 , further comprising:

transmitting a user feedback signal input during the playback duty cycle to the master device.

4. The method of claim 1 , wherein the playback duty cycle is determined based on a frame rate of the digital content.

5. The method of claim 1 , wherein a time difference between the playback delay times included in the playback delay time list is within a range of the playback duty cycle.

6. The method of claim 1 , wherein in the calculating of the playback delay time correction amount, the playback delay time correction amount is determined by calculating the difference based on a playback delay time of a connected device which minimizes a difference between the playback delay time lists of the plurality of connected devices including the master device.

7. A method of synchronizing playback of a digital content between connected devices, the method comprising:

receiving a playback delay time from a plurality of connected devices during a playback duty cycle;

generating a playback delay time list by using the playback delay time received from each of the plurality of connected devices and a playback delay time of a master device, and calculating a playback sync timestamp by using the playback delay time list; and

transmitting the generated playback delay time list or a playback sync timestamp used in playback synchronization to the connected devices.

8. The method of claim 7 , wherein the playback sync timestamp for the playback synchronization is determined based on the playback delay time list or a time difference between the playback delay times included in the playback delay time list.

9. The method of claim 7 , wherein the playback duty cycle is determined based on a frame rate or channel information of the digital content.

10. The method of claim 7 , wherein the playback delay time correction amount is determined by calculating a difference based on a playback delay time of a connected device which minimizes the difference between the playback delay time lists of the plurality of connected devices including the master device receiving the playback delay time.

11. A method of synchronizing playback of a digital content between connected devices, the method comprising:

receiving, by a master device, a playback delay time from a plurality of connected devices during a playback duty cycle;

generating a playback delay time list by using the playback delay time received from each of the plurality of connected devices and a playback delay time of a master device, and calculating a playback sync timestamp by using the playback delay time list;

transmitting the generated playback delay time list or a playback sync timestamp used in playback synchronization to the connected devices;

receiving, by the plurality of connected devices, the playback delay time list or the playback sync timestamp used for the playback synchronization from the master device during the playback duty cycle;

calculating a playback delay time correction amount by referring to the playback delay time list in order for the plurality of connected devices including the master device to synchronize playback;

correcting, by the master device and the plurality of connected devices, the playback sync timestamp used for the playback synchronization according to the playback delay time correction amount; and

playing a digital content according to the corrected playback sync timestamp.

12. A connected device for synchronizing playback of a digital content, the connected device comprising:

a reception unit configured to receive a playback delay time list or a playback sync timestamp from a master device during a playback duty cycle;

a playback delay time correction amount calculation unit configured to calculate a playback delay time correction amount by referring to the playback delay time list in order to synchronize playback between a plurality of connected devices including the master device;

a playback sync timestamp correction unit configured to correct a playback sync timestamp used for the playback synchronization according to the playback delay time correction amount; and

a playback unit configured to play a digital content according to the corrected playback sync timestamp.

13. A master device for synchronizing playback of a digital content between connected devices, the maser device comprising:

a reception unit configured to receive a playback delay time from a plurality of connected devices during a playback duty cycle;

a playback delay time list generation unit configured to generate a playback delay time list by using a playback delay time received from each of the plurality of connected devices, and a playback delay time of the master device; and

a transmission unit configured to transmit the generated playback delay time list or a playback sync timestamp used in playback synchronization to the connected devices.

14. A system for synchronizing playback of a digital content between connected devices, the system comprising:

one or more connected devices including:

a reception unit configured to receive a playback delay time list or a playback sync timestamp from a master device during a playback duty cycle;

a playback delay time correction amount calculation unit configured to calculate a playback delay time correction amount by referring to the playback delay time list in order to synchronize playback between a plurality of connected devices including the master device;

a playback sync timestamp correction unit configured to correct a playback sync timestamp used for the playback synchronization according to the playback delay time correction amount; and

one or more connected devices including a playback unit which plays a digital contents according to the corrected playback sync timestamp; and

a master device including:

a reception unit configured to receive a playback delay time from a plurality of connected devices during a playback duty cycle;

a playback delay time list generation unit configured to generate a playback delay time list by using a playback delay time received from each of the plurality of connected devices, and a playback delay time of the master device; and

a transmission unit configured to transmit the generated playback delay time list or a playback sync timestamp used in playback synchronization to the connected devices.

15. A computer-readable recording medium in which a program for executing the method of claim 1 in a computer is recorded.