Clock synchronization for audio playback devices
First Claim
1. A method for synchronizing clocks on a plurality of audio playback devices, the method comprising:
- receiving a broadcast/multicast acknowledgement packet from a synchronization agent at a first audio playback device of the plurality of audio playback devices;
receiving the broadcast/multicast acknowledgement packet at a time server;
recording a first timestamp representing a time when the acknowledgement packet was received by the first audio playback device;
receiving a broadcast/multicast timestamp packet from the time server at the first audio playback device, wherein the timestamp packet includes a second timestamp representing a time when the time server received the acknowledgement packet from the synchronization agent; and
updating a local clock time on the first audio playback device based on the first timestamp and the second timestamp,wherein the method enables clock synchronization among the plurality of audio playback devices for synchronized playback of audio content via the plurality of audio playback devices, andwherein the synchronization agent and the time server are separate and discrete devices that are configured to communicate over a local area network.
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Abstract
A method is provided for synchronizing clocks on a plurality of audio playback devices. The method includes receiving a broadcast/multicast acknowledgement packet from a synchronization agent at a first audio playback device of the plurality of audio playback devices. A first timestamp representing a time when the acknowledgement packet was received by the first audio playback device is recorded. A broadcast/multicast timestamp packet is received from a time server at the first audio playback device. The timestamp packet includes a second timestamp representing a time when the time server received the acknowledgement packet from the synchronization agent. A local clock time on the first audio playback device is updated based on the first timestamp and the second timestamp. The method enables clock synchronization among the plurality of audio playback devices for synchronized playback of streamed audio via the plurality of audio playback devices.
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Citations
19 Claims
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1. A method for synchronizing clocks on a plurality of audio playback devices, the method comprising:
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receiving a broadcast/multicast acknowledgement packet from a synchronization agent at a first audio playback device of the plurality of audio playback devices; receiving the broadcast/multicast acknowledgement packet at a time server; recording a first timestamp representing a time when the acknowledgement packet was received by the first audio playback device; receiving a broadcast/multicast timestamp packet from the time server at the first audio playback device, wherein the timestamp packet includes a second timestamp representing a time when the time server received the acknowledgement packet from the synchronization agent; and updating a local clock time on the first audio playback device based on the first timestamp and the second timestamp, wherein the method enables clock synchronization among the plurality of audio playback devices for synchronized playback of audio content via the plurality of audio playback devices, and wherein the synchronization agent and the time server are separate and discrete devices that are configured to communicate over a local area network. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An audio system comprising:
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a time server; a synchronization agent; and a plurality of audio playback devices for providing synchronized playback of audio content, wherein each audio playback device of the plurality is configured to; receive a broadcast/multicast acknowledgement packet from a synchronization agent; record a first timestamp representing a time when the acknowledgement packet was received; receive a broadcast/multicast timestamp packet from the time server, wherein the timestamp packet includes a second timestamp representing a time when the time server received the acknowledgement packet from the synchronization agent; update a local clock time based on the first timestamp and the second timestamp, such that the local clock time corresponds to that of the other audio playback devices; and using the updated local clock time to render the audio content in synchrony with the other audio playback devices. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A non-transitory computer readable storage medium including a set of instructions for execution by a processor, the set of instructions, when executed, causes the processor to:
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receive a broadcast/multicast acknowledgement packet via the network interface from a synchronization agent; record a first timestamp representing a time when the acknowledgement packet was received; receive a broadcast/multicast timestamp packet from a time server, wherein the timestamp packet includes a second timestamp representing a time when the time server received the acknowledgement packet from the synchronization agent; update a local clock time based on the first timestamp and the second timestamp; and using the updated local clock time to enable synchronized playback of the audio content among a plurality of audio playback devices. - View Dependent Claims (17)
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18. An audio playback device comprising:
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a digital-to-analog converter configured to receive an audio stream comprising a digital representation of audio content via a network and convert to analog form; an electro-acoustic transducer; a network interface; a processor coupled to the digital-to-analog converter, the electro-acoustic transducer, and the network interface; and instructions stored on a non-transitory computer-readable media that, when executed, cause the processor to; receive a broadcast/multicast acknowledgement packet via the network interface from a synchronization agent; record a first timestamp representing a time when the acknowledgement packet was received by the playback device; receive a broadcast/multicast timestamp packet via the network interface from a time server, wherein the timestamp packet includes a second timestamp representing a time when the time server received the acknowledgement packet from the synchronization agent; update a local clock time based on the first timestamp and the second timestamp, such that the local clock time corresponds to that of at least one other audio playback device on the network; and using the updated local clock time to render the audio content in synchrony with the at least one other audio playback devices. - View Dependent Claims (19)
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Specification