Calibrating Media Playback Channels for Synchronized Presentation

A method comprising:

• sending, by a media device, calibration content to a first playback device associated with a first playback channel;
• storing, by the media device, a transmission time indicating when the calibration content was sent to the first playback device, the transmission time determined based on a first clock on the media device;
• receiving, by the media device from a sensor device, calibration data, the calibration data including a portion of calibration content presented by the first playback device and detected by the sensor device;
• determining, by the media device, a received time indicating when the calibration data was received by the media device, the received time determined based on the first clock on the media device;
• and
• calculating, by the media device, a propagation latency value based on the transmission time, the received time, the portion of the detected calibration content, and a time in flight value representing an amount of time it takes for a message to be received at the media device after being sent by the sensor device.

A sensor device comprising:

• one or more processors;
• and
• a non-transitory computer readable medium including one or more sequences of instructions that, when executed by the processors, cause the processors to perform operations comprising:
• detecting, by the sensor device, a portion of calibration content presented by a first playback device, the portion of calibration content transmitted to the first playback device from a media device at a transmission time determined based on a first clock at the media device;
• generating, by the sensor device, calibration data, the calibration data including the portion of the detected calibration content and a detection time indicating when the portion of the calibration content was detected by the sensor device, the detection time determined based on a second clock on the sensor device;
• sending, by the sensor device, the calibration data to the media device, wherein the media device calculates a propagation latency value based on a transmission time, the portion of the detected calibration content, and the detection time indicated in the calibration data.