Dynamic lip-sync compensation for truly wireless bluetooth devices
Audio systems in which a primary audio device ( 28 ) communicates wirelessly with a second audio device ( 36 ) include a latency caused by the communication between the two audio devices. For example, a truly wireless audio device can comprise a first earpiece and a second earpiece. The electronic device ( 10 ) that is playing a media file transmits audio data to the first earpiece. The first earpiece then transmits a portion of the audio data to the second earpiece. This communication between the first and second earpiece causes a latency that the system can account for in order to synchronize a video playback with the corresponding audio playback on the wireless headset.
1. A system for synchronizing audio-video playback, comprising:
an electronic device; and
a primary audio device configured to:
wirelessly receive, from the electronic device, a first portion of audio data for playback with the primary audio device, and a second portion of audio data for playback with a second audio device;
wirelessly transmit the second portion of audio data to the second audio device;
wirelessly receive an acknowledgment signal from the second audio device, the acknowledgment signal acknowledges receipt of the second portion of audio data at the second audio device;
determine an audio delay time based on receipt of the acknowledgment signal;
determine a change in audio delay time between the audio delay time and a previous audio delay time;
compare the change in audio delay time to a threshold; and
wirelessly transmit the audio delay time to the electronic device based on a determination that the absolute value of the change in audio delay time is greater than the threshold, the audio delay time accounts for a latency caused by wirelessly transmitting the second portion of audio data from the primary audio device to the second audio device;
wherein the electronic device is configured to delay a video playback based on the audio delay time.
2. The system of claim 1 , wherein the primary audio device uses Bluetooth communication to receive the first portion of audio data and the second portion of audio data from the electronic device, and to transmit the audio delay time to the electronic device.
3. The system of claim 2 , wherein the primary audio device utilizes an Advanced Audio Distribution Profile (A2DP) or an Audio/Video Remote Control Profile (AVRCP) to transmit the audio delay time to the electronic device.
4. A method for determining and transmitting an audio delay time, comprising:
wirelessly receiving, from an electronic device, a first portion of audio data for playback with a primary audio device, and a second portion of audio data for playback with a second audio device;
wirelessly transmitting the second portion of audio data to the second audio device;
wirelessly receiving an acknowledgment signal from the second audio device, the acknowledgment signal acknowledges receipt of the second portion of audio data at the second audio device;
determining the audio delay time based on receipt of the acknowledgment signal;
determining a change in audio delay time between the audio delay time and a previous audio delay time;
comparing the change in audio delay time to a threshold; and
wirelessly transmitting the audio delay time to the electronic device based on a determination that the absolute value of the change in audio delay time is greater than the threshold, wherein the audio delay time accounts for a latency caused by wirelessly transmitting the second portion of audio data to the second audio device.
5. The method of claim 4 , further comprising:
determining that the second audio device did not receive the second portion of audio; and
adjusting the audio delay time to account for audio playback by only the primary audio device.
6. The method of claim 4 , wherein Bluetooth communication is used for wirelessly receiving the first portion of audio data and the second portion of audio data, and for wirelessly transmitting the audio delay time to the electronic device.
7. The method of claim 6 , wherein the primary audio device utilizes an Advanced Audio Distribution Profile (A2DP) or an Audio/Video Remote Control Profile (AVRCP) to transmit the audio delay time to the electronic device.
8. The method of claim 4 , wherein determining the audio time delay comprises determining a time difference between transmitting the second portion of audio and receiving the acknowledgment signal from the second audio device, and dividing the time difference by two.
9. A primary audio device comprising a communications interface and a control circuit configured to carry out the method of claim 4 .
10. A method for synchronizing audio-video playback using a system comprising an electronic device and a primary audio device, the method comprising:
wirelessly receiving, at the primary audio device, a first portion of audio data for playback with the primary audio device, and a second portion of audio data for playback with a second audio device;
wirelessly transmitting the second portion of audio data from the primary audio device to the second audio device;
wirelessly receiving an acknowledgment signal from the second audio device, the acknowledgment signal acknowledges receipt of the second portion of audio data at the second audio device;
determining an audio delay time based on receipt of the acknowledgment signal;
determining a change in audio delay time between the audio delay time and a previous audio delay time;
comparing the change in audio delay time to a threshold;
wirelessly transmitting the audio delay time from the primary audio device to the electronic device based on a determination that the absolute value of the change in audio delay time is greater than the threshold, the audio delay time accounts for a latency caused by wirelessly transmitting the second portion of audio data from the primary audio device to the second audio device; and
delaying a video playback at the electronic device, based on the audio delay time.
11. The method of claim 10 , wherein the steps of wirelessly receiving the first portion of audio data and the second portion of audio data from the electronic device, and transmitting the audio delay time to the electronic device are performed using Bluetooth communication.
12. The method of claim 11 , wherein the step of wirelessly transmitting the audio delay time to the electronic device utilizes an Advanced Audio Distribution Profile (A2DP) or an Audio/Video Remote Control Profile (AVRCP).
13. The method of claim 10 , further comprising:
determining, at the primary audio device, that the second audio device did not receive the second portion of audio; and
adjusting the audio delay time to account for audio playback by only the primary audio device.