Synchronizing digital audio to digital video
First Claim
1. An audio/video input/output (I/O) apparatus for acquiring digital audio samples from one or multiple channels of input audio and, alternately, synthesizing digital audio samples into one or multiple channels of output audio, the apparatus comprising:
- a video I/O port circuit generating a video-rate clock, said video I/O port circuit comprising a video input port configured to convert input analog video into digital video, and a video output port configured to synthesize output analog video from digital video; and
an audio I/O port circuit comprising a frequency synthesizer connected to receive said video-rate clock from said video I/O port and configured to derive am audio sampling clock based on said video-rate clock, an audio input port configured to sample and convert input analog audio into digital audio samples according to said sampling clock, and an audio output port configured to synthesize digital audio samples into output analog audio according to said sampling clock.
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Accused Products
Abstract
An audio/video input/output (I/O) port apparatus for acquiring digital audio samples from one or multiple channels of input audio and synthesizing digital audio samples into one or multiple channels of output audio. The apparatus comprises a video I/O port, a frequency synthesizer, and an audio I/O port. The video I/O port generates a video-rate clock, and is configured to digitize input video into digital video, and to synthesize output video from digital video. The frequency synthesizer is configured to derive an audio sampling clock based on the video-rate clock. The audio I/O port is configured to sample input audio and convert it into digital audio samples according to the sampling clock, and to synthesize digital audio samples into output audio according to the sampling clock. The apparatus ensures that the video and audio data track together, both when inputting the information from an external source and when outputting the audio/video data streams. The technique is particularly valuable in video editing, where it is critical to establish and maintain synchronization between the video of a speaking person and the audio representing the spoken material.
126 Citations
39 Claims
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1. An audio/video input/output (I/O) apparatus for acquiring digital audio samples from one or multiple channels of input audio and, alternately, synthesizing digital audio samples into one or multiple channels of output audio, the apparatus comprising:
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a video I/O port circuit generating a video-rate clock, said video I/O port circuit comprising a video input port configured to convert input analog video into digital video, and a video output port configured to synthesize output analog video from digital video; and an audio I/O port circuit comprising a frequency synthesizer connected to receive said video-rate clock from said video I/O port and configured to derive am audio sampling clock based on said video-rate clock, an audio input port configured to sample and convert input analog audio into digital audio samples according to said sampling clock, and an audio output port configured to synthesize digital audio samples into output analog audio according to said sampling clock. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An audio/video input apparatus for acquiring one or multiple channels of digital audio samples, the apparatus comprising:
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a video input port configured to convert input analog video into digital video and generate a video-rate clock; a frequency synthesizer connected to receive said video-rate clock from said video input-port and configured derive an audio sampling clock based on said video-rate clock; and an audio input port configured to sample and convert input analog audio into digital audio samples according to said sampling clock. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. An audio/video output apparatus for synthesizing one or multiple channels of digital audio samples into output audio, the apparatus comprising:
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a video output port configured to synthesize output analog video from digital video and generating a video-rate clock; a frequency synthesizer connected to receive said video-rate clock from said video output port and configured to derive an audio sampling clock based on said video-rate clock; and an audio output port configured to synthesize output analog audio from digital audio samples according to said sampling clock. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A method for acquiring video and one or more channels of audio and storing them in digital form on a storage device of a computer, the method comprising the steps:
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receiving said video at a video input port; detecting one or more synchronization signals in said video; frequency-synthesizing an audio sampling clock from said synchroniztion signals in a frequency synthesizing circuit connected to receive said synchronization signals from said video input port; receiving said audio at an audio input port, said audio input port clocked by said audio sampling clock; and storing said received video and received audio on the storage device.
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Specification