Synchronizing playback of multimedia between in-vehicle and mobile devices
Synchronizing playback of multimedia content between playback devices integrated into a primary device, such as an in-vehicle infotainment (IVI) system and one or more nearby secondary devices, such as mobile devices, being served multimedia content by the IVI system. The IVI system determines a playback latency of each mobile device and serves the multimedia content to each primary and secondary playback device with a respective delay based on a difference between a maximum playback latency across all playback devices and the respective determined playback latency. In some implementations, playback latencies may be determined using an audio signal. In other implementations, playback latencies may be determined using satellite-synchronized timestamps.
1 . A method, comprising:
sending a first message from a primary device to a first secondary device, comprising first multimedia information and an instruction to record a first time at which the first secondary device outputs the first multimedia information via a first output device of the first secondary device, wherein the primary device and the first secondary device have independently synchronized their respective clocks to an external reference based on global navigation satellite system (GNSS) transmissions;
receiving a first response from the first secondary device at the primary device, the first response comprising the first time;
determining a first duration based on a difference between a time at the sending of the first message and the first time;
sending, at a start time, a first multimedia message comprising first multimedia information from the primary device to the first secondary device for outputting via the first output device; and
outputting, at a time substantially equal to the start time plus the first duration, the first multimedia information via an output device of the primary device.
2 . The method of claim 1 , wherein:
the first multimedia information comprises first graphical information.
3 . The method of claim 1 , wherein:
the first multimedia information comprises first audio information.
4 . The method of claim 1 , wherein:
the first multimedia message further comprises first multimedia audio information for outputting via a first speaker of the first secondary device; wherein the method further comprises:
outputting, at a time substantially equal to the start time plus the first duration, the first multimedia audio information via a speaker of the primary device.
5 . The method of claim 1 , further comprising:
sending a second message from the primary device to a second secondary device;
receiving a second response from the second secondary device at the primary device;
determining a second duration based on the second message and the second response;
determining that the first duration is greater than the second duration; and
sending, at a time substantially equal to the start time plus the first duration minus the second duration, a second multimedia message comprising the first multimedia information from the primary device to the second secondary device for outputting via a second output device of the second secondary device.
6 . The method of claim 5 , wherein:
the first multimedia message further comprises first multimedia audio information for outputting via a first speaker of the first secondary device; and
the second multimedia message further comprises the first multimedia audio information for outputting via a first speaker of the second secondary device; wherein the method further comprises:
outputting, at a time substantially equal to the start time plus the first duration, the first multimedia audio information via a speaker of the primary device.
7 . The method of claim 1 , further comprising:
sending a second message from the primary device to a second secondary device;
receiving a second response from the second secondary device at the primary device;
determining a second duration based on the second message and the second response; and
determining that the first duration is greater than the second duration; wherein
the sending of the first multimedia message is a broadcast to the first secondary device and the second secondary device, for outputting the first multimedia information via the first output device and a second output device of the second secondary device, and comprises an instruction to the second secondary device to delay outputting the first multimedia information for a duration substantially equal to the first duration minus the second duration.
8 . The method of claim 7 , wherein:
the first multimedia message further comprises first multimedia audio information, for outputting via a first speaker of the first secondary device and for outputting via a second speaker of the second secondary device, and an instruction to the second secondary device to delay outputting the first multimedia audio information for a duration substantially equal to the first duration minus the second duration; wherein the method further comprises:
outputting, at a time substantially equal to the start time plus the first duration, the first multimedia audio information via a speaker of the primary device.
9 . The method of claim 1 wherein:
the primary device is an in-vehicle infotainment system.
10 . The method of claim 1 wherein:
the first secondary device is a mobile device.
11 . The method of claim 1 wherein:
the first message and the first multimedia message are sent via a wireless network.
12 . The method of claim 1 wherein the first multimedia information comprises at least one of:
pre-recorded video information; or
live-streaming video information.
13 . A system, comprising:
one or more memories; and
one or more processors configured to execute instructions stored in the one or more memories to:
send a first message from a primary device to a first secondary device, comprising first multimedia information and an instruction to record a first time at which the first secondary device outputs the first multimedia information via a first output device of the first secondary device, wherein the primary device and the first secondary device have independently synchronized their respective clocks to an external reference based on global navigation satellite system (GNSS) transmissions;
receive a first response from the first secondary device at the primary device, the first response comprising the first time;
determine a first duration based on a difference between a time at the sending of the first message and the first time;
send, at a start time, a first multimedia message comprising first multimedia information from the primary device to the first secondary device for outputting via the first output device; and
output, at a time substantially equal to the start time plus the first duration, the first multimedia information via an output device of the primary device.
14 . The system of claim 13 , wherein the instructions include instructions to:
send a second message from the primary device to a second secondary device;
receive a second response from the second secondary device at the primary device;
determine a second duration based on the second message and the second response;
determine that the first duration is greater than the second duration; and
send, at a time substantially equal to the start time plus the first duration minus the second duration, a second multimedia message comprising the first multimedia information from the primary device to the second secondary device for outputting via a second output device of the second secondary device.
15 . The system of claim 13 , wherein the instructions include instructions to:
send a second message from the primary device to a second secondary device;
receive a second response from the second secondary device at the primary device;
determine a second duration based on the second message and the second response; and
determine that the first duration is greater than the second duration; wherein the instruction to send the first multimedia message is an instruction to broadcast the first multimedia message to the first secondary device and the second secondary device, for outputting the first multimedia information via the first output device and a second output device of the second secondary device; and
the first multimedia message comprises an instruction to the second secondary device to delay outputting the first multimedia information for a duration substantially equal to the first duration minus the second duration.
16 . A non-transitory computer-readable medium storing instructions operable to cause one or more processors to perform operations comprising:
sending a first message from a primary device to a first secondary device, comprising first multimedia information and an instruction to record a first time at which the first secondary device outputs the first multimedia information via a first output device of the first secondary device, wherein the primary device and the first secondary device have independently synchronized their respective clocks to an external reference based on global navigation satellite system (GNSS) transmissions;
receiving a first response from the first secondary device at the primary device, the first response comprising the first time;
determining a first duration based on a difference between a time at the sending of the first message and the first time;
sending, at a start time, a first multimedia message comprising first multimedia information from the primary device to the first secondary device for outputting via the first output device; and
outputting, at a time substantially equal to the start time plus the first duration, the first multimedia information via an output device of the primary device.
17 . The medium of claim 16 , the operations further comprising:
sending a second message from the primary device to a second secondary device;
receiving a second response from the second secondary device at the primary device;
determining a second duration based on the second message and the second response;
determining that the first duration is greater than the second duration; and
sending, at a time substantially equal to the start time plus the first duration minus the second duration, a second multimedia message comprising the first multimedia information from the primary device to the second secondary device for outputting via a second output device of the second secondary device.
18 . The medium of claim 16 , the operations further comprising:
sending a second message from the primary device to a second secondary device;
receiving a second response from the second secondary device at the primary device;
determining a second duration based on the second message and the second response; and
determining that the first duration is greater than the second duration; wherein
the sending of the first multimedia message is a broadcast to the first secondary device and the second secondary device, for outputting the first multimedia information via the first output device and a second output device of the second secondary device; and
the first multimedia message comprises an instruction to the second secondary device to delay outputting the first multimedia information for a duration substantially equal to the first duration minus the second duration.