Audio and video buffer synchronization based on actual output feedback
A method and system for keeping endpoints such as speakers and displays synchronized via feedback based on the actual output of the endpoints. A source of audiovisual content transmits corresponding digital data to one or more endpoints, such as over a home network, where it may be buffered and/or decoded for playback. Microphones or the like sense actual (post-buffering/decoding) output from one or more endpoints and feed it back to a synchronization mechanism. The synchronization mechanism employs pattern matching or similar techniques to determine whether and how to adjust the timing of endpoints to synchronize their actual outputs. Synchronization may be accomplished by controllably delaying transmission and/or other processing, by controllably changing the rate of advancing in a buffer, and/or by jumping ahead in a buffer. The synchronization mechanism may adjust multiple endpoints, e.g., when limited buffer size limits the amount of adjustment a single device can provide.
1. In a system that includes a first device for transmitting audio signals to a remote endpoint, wherein the first device and the remote endpoint both buffer the audio signals before outputting the audio signals, a method for synchronizing the output of the audio signals between the first device and the remote endpoint, comprising:
the first device transmitting audio signals to the remote endpoint such that the remote endpoint buffers the audio signals in a buffer at the remote endpoint prior to outputting the signals, the first device also buffering the same audio signals in a buffer of the first device;
the first device and the remote endpoint outputting the audio signals; and
receiving input from a user at either the first device or the remote endpoint, the user input causing the first device or the remote endpoint to either jump ahead or back in its buffer, or speed up or slow down the rate of output of the audio signals in its buffer.
2. In a system that includes a first device for transmitting audio signals to a remote endpoint, wherein the first device and the remote endpoint both buffer the audio signals before outputting the audio signals, a method for synchronizing the output of the audio signals between the first device and the remote endpoint, comprising:
the first device encoding and transmitting audio signals to the remote endpoint such that the remote endpoint buffers the audio signals in a buffer at the remote endpoint prior to outputting the signals, the first device also buffering the same audio signals in a buffer of the first device;
the first device and the remote endpoint outputting the audio signals; and
receiving input from a user at the first device, the user input causing the first device to add data to the audio signals that are encoded and transmitted to the remote endpoint.
3. The method of claim 2 , further comprising the user input causing the first device to remove data from the audio signals that are encoded and transmitted to the remote endpoint.
4. The method of claim 2 , further comprising the user input causing the first device to temporarily pause the output of the audio signals at the first device.