US5748842A
Expired / Lapsed
US
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Synchronizing digital audio to digital video
Assignee: Acoustic Technology LLC
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Filing: 1996-04-08
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Granted: 1998-05-05
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Expires: 2016-04-08
Abstract
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.
Inventors
- 👤 Daniel J. Holmes
- 👤 John W. Molnar
- 👤 Morton H. Tarr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:50
CPC Classifications
H; H04; H04N; H04N21/00; H04N21/40; H04N21/43; H04N21/4302; H04N21/4305; G; G11; G11B; G11B27/00; G11B27/02; G11B27/031; G11B27/034; G11B27/10; H04N21/41; H04N21/426; H04N21/4307; H04N21/43072; H04N21/434; H04N21/4341; H04N5/00; H04N5/04; H04N5/08; H04N5/44; H04N5/60; H04N5/602; H04N5/76; H04N5/765; H04N7/00; H04N7/24; H04N7/52; H04N7/54; H04N7/56; H04N9/00; H04N9/79; H04N9/80; H04N9/802; G11B2220/00; G11B2220/90; G11B27/022; G11B27/024; G11B27/032; G11B27/34; H04N9/64; H04N9/641
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
155 words
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 synchronization signal, 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 synchronization signal from said video I/O port and configured to derive an audio sampling clock based on said video synchronization signal, 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.
Claim 2
Dependent Claim
155 words
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 synchronization signal, 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 synchronization signal from said video I/O port and configured to derive an audio sampling clock based on said video synchronization signal, 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.
Claim 3
Dependent Claim
69 words
The audio/video I/O apparatus of claim 1 further comprising: a general purpose computer with a storage device and a peripheral slot; and peripheral interface circuitry installed in said peripheral slot and configured to transfer said digital video and digital audio samples from said audio input and video input ports to said storage device, and to transfer data from said storage device to said audio output and video output ports.
Claim 4
Dependent Claim
34 words
The audio/video I/O apparatus of claim 2 wherein said peripheral interface circuitry further comprises FIFOs for coupling asynchronous operation of said computer to synchronous operation of said video and audio input and output ports.
Claim 5
Dependent Claim
50 words
The audio/video I/O apparatus of claim 2 wherein said peripheral interface circuitry further comprises a CODEC for compressing said digital video into compressed video data for storing on said storage device and for decompressing said video data as they are transferred from said storage device to said video output port.
Claim 6
Dependent Claim
54 words
The audio/video I/O apparatus of claim 1 wherein said frequency synthesizer further comprises: an oversampled clock synthesizer that generates an oversampled clock whose frequency is at least twice as great as the frequency of said audio sampling clock; and a frequency divider that frequency divides said oversampled clock to generate said audio sampling clock.
Claim 7
Dependent Claim
100 words
The audio/video I/O apparatus of claim 1 further comprising a digital signal processor programmed to: selectively associate a varying number of digital audio samples to each respective frame of said digital video to achieve a precise ratio of the number of said digital audio samples over a finite time to the number of associated frames of said digital video over said finite time; and selectively associate a varying number of said digital audio samples to each respective frame of said digital video as said digital audio samples and said digital video are presented to said video and audio output ports.
Claim 8
Dependent Claim
100 words
The audio/video I/O apparatus of claim 1 further comprising a digital signal processor programmed to: selectively associate a varying number of digital audio samples to each respective frame of said digital video to achieve a precise ratio of the number of said digital audio samples over a finite time to the number of associated frames of said digital video over said finite time; and selectively associate a varying number of said digital audio samples to each respective frame of said digital video as said digital audio samples and said digital video are presented to said video and audio output ports.
Claim 9
Dependent Claim
63 words
The audio/video I/O apparatus of claim 1 wherein said audio input port further comprises: an analog-to-digital converter for converting said input analog audio into said digital audio samples, said analog-to-digital converter being clocked by said audio sampling clock; and a digital-to-analog converter for converting said digital audio samples to said output analog audio, said digital-to-analog converter being clocked by said audio sampling clock.
Claim 10
Dependent Claim
89 words
The audio/video I/O apparatus of claim 1 further comprising: a host computer with a storage device for storing said digital audio samples and said digital video; first and second FIFOs for storing said digital audio samples between said audio input port and said storage device; third and fourth FIFOs for storing said digital audio samples between said storage device and said audio output port; and a digital signal processor for controlling flow of said digital audio samples between said first and second FIFOs and said third and fourth FIFOs.
Claim 11
Dependent Claim
87 words
An audio/video input apparatus for acquiring one or multiple channels of digital audio samples, the apparatus comprising: a video input port configured to convert input analog video into digital video and generate a video synchronization signal; a frequency synthesizer connected to receive said video synchronization signal from said video input port and configured to derive an audio sampling clock based on said video synchronization signal; and an audio input port configured to sample and convert input analog audio into digital audio samples according to said sampling clock.
Claim 12
Dependent Claim
87 words
An audio/video input apparatus for acquiring one or multiple channels of digital audio samples, the apparatus comprising: a video input port configured to convert input analog video into digital video and generate a video synchronization signal; a frequency synthesizer connected to receive said video synchronization signal from said video input port and configured to derive an audio sampling clock based on said video synchronization signal; and an audio input port configured to sample and convert input analog audio into digital audio samples according to said sampling clock.
Claim 13
Dependent Claim
53 words
The audio/video input apparatus of claim 10 further comprising: a general purpose computer with a storage device and a peripheral slot; and peripheral interface circuitry installed in said peripheral slot and configured to transfer said digital video and digital audio samples from said audio input and video input ports to said storage device.
Claim 14
Dependent Claim
33 words
The audio/video input apparatus of claim 11 wherein said peripheral interface circuitry further comprises a FIFO for coupling asynchronous operation of said computer to synchronous operation of said video and audio input ports.
Claim 15
Dependent Claim
31 words
The audio/video input apparatus of claim 11 wherein said peripheral interface circuitry further comprises a CODEC for compressing said digital video into compressed video data for storing on said storage device.
Claim 16
Dependent Claim
65 words
The audio/video input apparatus of claim 10 wherein the video input port further comprises: a detector configured to detect a synchronizing signal of said input analog video; and a pulse generator configured to provide an input synchronization pulse to said audio input port, said input synchronization pulse being generated for each frame of said input analog video and being based on said detected synchronizing signal.
Claim 17
Dependent Claim
54 words
The audio/video input apparatus of claim 10 wherein said frequency synthesizer further comprises: an oversampled clock synthesizer that generates an oversampled clock whose frequency is at least twice as great as the frequency of said audio sampling clock; and a frequency divider that frequency divides said oversampled clock to generate said audio sampling clock.
Claim 18
Dependent Claim
63 words
The audio/video input apparatus of claim 10 further comprising: a digital signal processor programmed to selectively associate a varying number of digital audio samples to each respective frame of said digital video to achieve an accurate ratio of the number of said digital audio samples over a finite time to the number of associated frames of said digital video over said finite time.
Claim 19
Dependent Claim
63 words
The audio/video input apparatus of claim 10 further comprising: a digital signal processor programmed to selectively associate a varying number of digital audio samples to each respective frame of said digital video to achieve an accurate ratio of the number of said digital audio samples over a finite time to the number of associated frames of said digital video over said finite time.
Claim 20
Dependent Claim
38 words
The audio/video input apparatus of claim 10 wherein said audio input port further comprises an analog-to-digital converter for converting said input analog audio into said digital audio samples, said analog-to-digital converter being clocked by said audio sampling clock.
Claim 21
Dependent Claim
64 words
The audio/video input apparatus of claim 10 further comprising: a host computer with a storage device for storing said digital audio samples and said digital video; first and second FIFOs for storing said digital audio samples between said audio input port and said storage device; and a digital signal processor for controlling flow of said digital audio samples between said first and second FIFOS.
Claim 22
Dependent Claim
88 words
An audio/video output apparatus for synthesizing one or multiple channels of digital audio samples into output audio, the apparatus comprising: a video output port configured to synthesize output analog video from digital video and generating a video synchronization signal; a frequency synthesizer connected to receive said video synchronization signal from said video output port and configured to derive an audio sampling clock based on said video synchronization signal; and an audio output port configured to synthesize output analog audio from digital audio samples according to said sampling clock.
Claim 23
Dependent Claim
88 words
An audio/video output apparatus for synthesizing one or multiple channels of digital audio samples into output audio, the apparatus comprising: a video output port configured to synthesize output analog video from digital video and generating a video synchronization signal; a frequency synthesizer connected to receive said video synchronization signal from said video output port and configured to derive an audio sampling clock based on said video synchronization signal; and an audio output port configured to synthesize output analog audio from digital audio samples according to said sampling clock.
Claim 24
Dependent Claim
47 words
The audio/video output apparatus of claim 20 further comprising: a general purpose computer with a storage device and a peripheral slot; and peripheral interface circuitry installed in said peripheral slot and configured to transfer data from said storage device to said audio output and video output ports.
Claim 25
Dependent Claim
33 words
The audio/video output apparatus of claim 21 wherein said peripheral interface circuitry further comprises a FIFO for coupling asynchronous operation of said computer to synchronous operation of said video and audio output ports.
Claim 26
Dependent Claim
33 words
The audio/video output apparatus of claim 21 wherein said video peripheral further comprises a CODEC for decompressing said video data as they are transferred from said storage device to said video output port.
Claim 27
Dependent Claim
54 words
The audio/video output apparatus of claim 20 wherein said frequency synthesizer further comprises: an oversampled clock synthesizer that generates an oversampled clock whose frequency is at least twice as great as the frequency of said audio sampling clock; and a frequency divider that frequency divides said oversampled clock to generate said audio sampling clock.
Claim 28
Dependent Claim
51 words
The audio/video output apparatus of claim 20 further comprising: a digital signal processor programmed to selectively associate a varying number of said digital audio samples to each respective frame of said digital video as said digital audio samples and said digital video are presented to said video and audio output ports.
Claim 29
Dependent Claim
38 words
The audio/video output apparatus of claim 20 wherein said audio output port further comprises a digital-to-analog converter for converting said digital audio samples to said output analog audio, said digital-to-analog converter being clocked by said audio sampling clock.
Claim 30
Dependent Claim
64 words
The audio/video output apparatus of claim 20 further comprising: a host computer with a storage device for storing said digital audio samples and said digital video; first and second FIFOs for storing said digital audio samples between said storage device and said audio output port; and a digital signal processor for controlling flow of said digital audio samples between said first and second FIFOs.
Claim 31
Independent Claim
88 words
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: receiving said video at a video input port; generating a video synchronization signal based upon said video; deriving an audio sampling clock based upon said video synchronization signal; 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.
Claim 32
Independent Claim
88 words
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: receiving said video at a video input port; generating a video synchronization signal based upon said video; deriving an audio sampling clock based upon said video synchronization signal; 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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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-05-04 | 2001-11-03 | 2002-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-04 | 2005-11-03 | 2006-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-04 | 2009-11-03 | 2010-05-05 | $7700.00 | Window Closed / Lapsed |