Delay matching in audio/video systems
View Patent ↗An audio/video system comprises an audio signal processing path having an audio path delay and a video signal processing path having a video path delay. The audio path delay may be different from the video path delay. The audio path delay and/or the video path delay may change, for example because of replacement of a component within the audio signal processing path or the video signal processing path. Delay matching (synchronization) in the audio/video system comprises adjusting the audio path delay to be substantially equal to the video path delay. Matching the audio path delay to the video path delay generally includes adding delay to the signal processing path with the lesser delay.
1. An audio/video signal processing system, the system comprising:
an audio signal processing path that generates an audio stimulus;
a video signal processing path that generates a video stimulus;
a sensor that detects a difference between an audio path delay of the audio signal processing path based on the audio stimulus and a video path delay of the video signal processing path based on the video stimulus, the audio path delay including a delay associated with an audio speaker and the video path delay including a delay associated with a video display; and
a delay generator that adjusts the audio path delay to be substantially equal to the video path delay.
2. The system of claim 1 , wherein the delay generator adds delay into the video signal processing path when the audio path delay is greater than the video path delay, and adds delay into the audio signal processing path when the video path delay is greater than the audio path delay.
3. The system of claim 1 , wherein the audio signal processing path and the video signal processing path comprise a home theater system.
4. The system of claim 3 , wherein the home theater system comprises substitutable audio/video components.
5. The system of claim 1 , wherein the audio signal processing path and the video signal processing path include an audio/video processor, and wherein the delay generator is included within the audio/video processor.
6. The system of claim 1 , wherein the audio signal processing path and the video signal processing path include an audio/video processor, and wherein the delay generator is coupled to the audio/video processor.
7. The system of claim 1 , wherein the delay generator further adjusts the audio path delay equal to the video path delay with a resolution of less than about 1/30 th of a second.
8. The system of claim 1 , wherein the audio signal processing path includes a player of media content, the media content including the audio stimulus and the video stimulus.
9. The system of claim 8 , wherein the player of media content comprises a video game system.
10. The system of claim 8 , wherein the player of media content comprises the delay generator.
11. A method for audio/video signal processing, the method comprising:
generating an audio stimulus in an audio signal processing path, the audio stimulus including an output of an audio speaker;
generating a video stimulus in a video signal processing path, the video stimulus including an output of a video display;
detecting the audio stimulus after an output of the audio signal processing path;
detecting the video stimulus after an output of the video signal processing path;
measuring a time offset between the detected audio stimulus and the detected video stimulus; and
determining a calibration value that substantially cancels the measured time offset.
12. The method of claim 11 , further comprising calibrating an audio/video sensor for detecting the audio stimulus and the video stimulus by prompting a user to provide the audio stimulus and the video stimulus into the audio/video sensor.
13. The method of claim 11 , wherein detecting the audio stimulus and the video stimulus comprises sensing the audio stimulus and the video stimulus with an audio/video sensor.
14. The method of claim 11 , further comprising adding delay based on the calibration value to the audio path if the detected audio stimulus precedes the detected video stimulus.
15. The method of claim 11 , further comprising adding delay based on the calibration value to the video path if the detected video stimulus precedes the detected audio stimulus.
16. The method of claim 11 , further comprising correcting for measurement delays in a sensor configured to measure the time offset.
17. A system comprising:
an audio signal processing path with an audio path delay;
a video signal processing path with a video path delay; and
a delay generator that matches the audio path delay to the video path delay based at least in part on a detected audio path delay and a detected video path delay, the detected audio path delay including a delay associated with an audio speaker and the detected video path delay including a delay associated with a video display.
18. The system of claim 17 , wherein the audio signal processing path and the video signal processing path comprise a home theater system.
19. The system of claim 17 , wherein the delay generator adds delay into the video signal processing path when the audio path delay is greater than the video path delay and adds delay into the audio signal processing path when the video path delay is greater than the audio path delay.
20. The system of claim 17 , wherein the delay generator has a resolution of less than about 1/30 th of a second.
21. The system of claim 17 , further comprising:
one or more audio/video sensors that detect an audio output from the audio signal processing path and a video output from the video signal processing path;
measuring circuitry that measures a time difference between the audio output and the video output; and
calibration circuitry that substantially cancels the measured time difference.