Software-assisted wireless coordination of audio playback

A non-transitory computer-readable storage medium for use with an electronic device, the computer-readable storage medium storing a program module that, when executed by the electronic device, coordinates a playback operation by causing the electronic device to perform one or more operations comprising:

• maintaining coordination between a system clock provided by a system clock circuit in the electronic device and an interface clock provided by an interface clock circuit in the electronic device, wherein the interface clock has a higher frequency than the system clock;
• calculating, based on differences between receive times when an interface circuit in the electronic device received packets associated with a second electronic device and transmit times, included in the packets, when the second electronic device transmitted the packets, relative drift as a function of time between the interface clock and a second interface clock in the second electronic device, wherein a given packet includes a transmit time, based on the second interface clock, when the second electronic device transmitted the given packet;
• adjusting, based on the relative drift, the system clock circuit to eliminate the relative drift, wherein the relative drift, which is based on the interface clock, provides higher resolution than the system clock;
• determining a remaining time offset between the interface clock and the second interface clock;
• modifying, based on the remaining time offset, a future time, which was received from the interface circuit, when the electronic device is to perform the playback operation to determine a corrected future time;
• and
• performing the playback operation at the corrected future time.

A method for coordinating a playback operation, comprising:

• by a processor in an electronic device:
• maintaining coordination between a system clock provided by a system clock circuit in the electronic device and an interface clock provided by an interface clock circuit in the electronic device, wherein the interface clock has a higher frequency than the system clock;
• calculating, based on differences between receive times when an interface circuit in the electronic device received packets associated with the second electronic device and transmit times, included in the packets, when the second electronic device transmitted the packets, relative drift as a function of time between the interface clock and a second interface clock in the second electronic device, wherein a given packet includes a transmit time, based on the second interface clock, when the second electronic device transmitted the given packet;
• adjusting, based on the relative drift, the system clock circuit to eliminate the relative drift, wherein the relative drift, which is based on the interface clock, provides higher resolution than the system clock;
• determining a remaining time offset between the interface clock and the second interface clock;
• modifying, based on the remaining time offset, a future time, which was received from the interface circuit, when the electronic device is to perform the playback operation to determine a corrected future time;
• and
• performing the playback operation at the corrected future time.