Editor for combining digitally recorded audio signals

• US 4,351,007 A
• Filed: 01/21/1981
• Issued: 09/21/1982
• Est. Priority Date: 08/20/1979
• Status: Expired due to Term

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Youngquist, Robert J.
• Primary Examiner(s): Canney, Vincent P.
• Application Number:
  US06/226,616
• Time in Patent Office: 608 Days
• Field of Search: 360/13, 360/32
• US Class Current: 360/13
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 2220/913 Digital audio tape [DAT] format
• CPC Class Codes: G11B 27/002 Programmed access in sequence to a plurality of record carriers or indexed parts, e.g. tracks, thereof, e.g. for editing; transfer of record carriers from magazine G11B15/68, G11B17/10; G11B17/22
• CPC Class Codes: G11B 27/032 on tapes G11B27/036, G11B27/038 take precedence
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: G11B 27/036 Insert-editing
• CPC Class Codes: G11B 27/10 Indexing; Addressing; Timing or synchronising; Measuring tape travel
• CPC Class Codes: G11B 27/323 Time code signal, e.g. on a cue track as SMPTE- or EBU-time code
• CPC Class Codes: G11B 31/00 Arrangements for the associated working of recording or reproducing apparatus with related apparatus with cameras or projectors G03B31/00 ; recording/reproducing of music for electrophonic musical instruments G10H1/0033; automatic arrangements for answering calls or for recording messages for absent subscribers H04M1/64; telephonic communication systems adapted for combination with dictation recording and playback systems H04M11/10; connection of TV recorder with other related apparatus, e.g. TV camera or receiver, in which the TV signal is significantly involved H04N, e.g. H04N23/00, H04N5/765; combination of radio or TV with other apparatus, e.g. with vehicles H05K11/00

Abstract

An apparatus for editing digitally recorded audio signals in which entry and exit edit points are designated based on a display of data derived from audio signal data proximate to the edit points. The apparatus enables the automatic selected and combination of portions of audio signals on at least two channels to produce a composite audio signal digitally recorded on a record medium.

Claims

1. A method for editing and combining selected portions of digitally encoded audio signals recorded on at least one record medium to form a composite digitally encoded audio signal, comprising the steps of

(a) reproducing signals digitally recorded on said at least one record medium to present audible displays of audio signals recorded on said at least one medium,

(b) operating in response to said audible displays to designate tentative entry and exit edit point words defining the spatial locations of selected portions of said reproduced signals to be joined in sequence to form said composite signal,

(c) storing the tentative edit point words defining said spatial locations,

(d) presenting audible displays of selected portions of the audio signals which are proximate to said spatial locations defined by said tentative edit point words,

(e) iteratively refining said spatial locations defined by said edit point words in steps of discrete time intervals of decreasing duration by operating in response to repeated audible displays of the selected portions of the audio signals to establish increasingly refined entry and exit edit points,

(f) storing the refined edit point words, and

(g) switching between audio signals located on said at least one medium at spatial locations defined by said refined edit point words to sequentially join selected portions of said signals at the thus defined spatial locations to thereby form said composite digitally encoded audio signal.

2. A method according to claim 1, for editing and combining selected portions of digitally encoded audio signals recorded on one channel of a record medium on another channel of which is recorded a digital signal train representing time code data each segment of which identifies the spatial location of a corresponding segment of digitally encoded audio signal recorded on said another channel, said method further comprising the steps of

reproducing digital signals corresponding to said recorded time code data,

iteratively operating on said reproduced time code related signals in response to said audible displays to designate selected segments thereof as said tentative and refined exit and entry edit point words,

storing said selected segments designated as edit point words,

operating under control of said stored selected segments to combine portions of said digitally encoded audio signals to form said composite audio signal, and

forming a record of said composite signal on at least one channel of said record medium.

3. A method according to claim 1 for editing and combining selected portions of digitally encoded audio signals positioned in a succession of frames containing a predetermined number of data words representing the digital equivalents of increments of analog signals, comprising the further steps of

(a) progressively modifying the digital representation of a first predetermined number of frames of digitally encoded audio signals recorded on said at least one record medium preceding and following said exit point word to form a digital fade-out signal in which the digitally encoded audio signal within said first predetermined number of frames gradually decreases to zero amplitude at the last frame following said exit edit point word,

(b) progressively modifying the digital representation of a second predetermined number of frames of digitally encoded audio signals recorded on said record medium preceding and following said entry edit point word to form a digital fade-in signal in which the digitally encoded audio signal within said second predetermined number of frames gradually increases from zero amplitude at the first frame preceding said entry edit point word to its original digital state at the last frame following said entry edit point word,

(c) electrically summing in real time said digital fade-out and fade-in signals to provide a composite digital cross-fade signal of relatively constant equivalent amplitude, which at the first frame of the first predetermined number of frames preceding said exit edit point word is wholly derived from the first set of audio signals and which at the last frame of the second number of predetermined frames following said entry edit point word is wholly derived from the second set of audio signals, and

(d) recording onto a record medium digital signals derived from said first set of signals ending with the frame immediately preceding the first frame of said first predetermined number of frames, recording thereafter said cross-fade signal and recording after said cross-fade signal signals derived from said second set of signals beginning with the frame immediately following the last of the second number of predetermined frames following said entry edit point word.

4. A method according to claim 1, wherein said switching step comprises

operating on said selected portions of said audio signals to directly rerecord said portions onto another channel of record medium to provide a final edited composite digitally encoded audio signal.

5. A method according to claim 4, wherein said selected portions are located on first and second record media and wherein said switching step comprises

synchronizing the motion of both media with respect to associated playback transducers such that the refined entry edit point word on one of said channels is sensed immediately following the sensing of the refined exit point word on the other of said channels, and

directly recording onto a channel of record medium at least one said selected portion to provide on a single channel of record medium said composite signal consisting of said both components of said selected portions of digitally encoded audio signals.

10. A method according to claim 1, further comprising the step of retrieving said selected portions of said reproduced signals and storing said selected portions, such that said audible displays may thereafter be generated from said stored selected portions.

6. A method for editing and combining selected portions of digitally encoded audio signals recorded on a first and on a second record medium to form a composite digitally encoded audio signal, comprising the steps of

(a) presenting audible displays of audio signals recorded on said first and second media,

(b) operating in response to said audible displays to designate a tentative exit edit point word defining the spatial location of the end of a first portion of a displayed audio signal reproduced from said first medium and a tentative entry edit point word defining the spatial location of the beginning of a portion of another displayed audio signal reproduced from said second medium to be joined in sequence after said first portion to form said composite signal,

(c) storing the tentative edit point words,

(d) presenting an audible display of selected portions of the audio signals which are proximate to said tentative edit point words,

(e) iteratively refining the spatial location defined by the edit point words in steps of discrete time intervals of decreasing duration in response to repeated audible displays of the selected portions of the audio signals to establish increasingly refined exit and entry edit points,

(f) storing the refined edit point words, and

(g) synchronously playing said first and second media and combining selected portions of the audio signals as defined by the refined edit point words to form a composite audio signal by switching between audio signals located on said separate channels at the spatial locations defined by said refined edit point words.

7. A method according to claim 6, further comprising the steps of

(a) progressively modifying the digital representation of a first predetermined number of frames of digitally encoded audio signals recorded on said first medium preceding and following said exit edit point word to form a digital fade-out signal in which the digitally encoded audio signal amplitude within said first predetermined number of frames gradually decreases to zero amplitude at the last frame following said exit edit point word,

(b) progressively modifying the digital representation of a second predetermined number of frames of digitally encoded audio signals recorded on said second medium preceding and following said entry edit point word to form a digital fade-in signal in which the digitally encoded audio signal amplitude within said second predetermined number of frames gradually increases from zero amplitude at the first frame preceding said entry edit point word to its original digital state at the last frame following said entry edit point word,

(c) electrically summing in real time said digital fade-out and fade-in signals to provide a composite digital cross-fade signal of relatively constant equivalent amplitude, which at the first frame of the first predetermined number of frames preceding said exit edit point word is wholly derived from the first set of audio signals and which at the last frame of the second number of predetermined frames following said entry edit point word is wholly derived from the second set of audio signals, and

(d) recording onto a record medium digital signals derived from said first set of signals ending with the frame immediately preceding the first frame of said first predetermined number of frames, recording thereafter said cross-fade signal and recording after said cross-fade signal signals derived from said second set of signals beginning with the frame immediately following the last of the second number of predetermined frames following said entry edit point word.

8. A method for editing and combining selected portions of digitally encoded audio signals recorded on separate channels on record medium to form a composite digitally encoded audio signal, comprising the steps of

(a) iteratively reproducing on a first digital audio recorder audio signals recorded on a first of said channels to provide an audible display thereof and refining in steps of discrete time intervals of decreasing duration an increasingly refined exit edit point which defines the spatial location of the end of a portion of that signal to be sequentially followed by a portion of a signal from a second channel;

(b) storing digital information representative of said exit edit point;

(c) iteratively reproducing on a second digital audio recorder audio signals recorded on said second of said channels and refining in steps of discrete time intervals of decreasing duration an increasingly refined entry edit point which defines the spatial location of the beginning of a signal portion to sequentially follow the end of the signal portion defined by the exit edit point;

(d) storing digital information representative of said entry edit point;

(e) previewing a proposed edited composite signal by

(i) synchronously reproducing on said first recorder audio signals recorded on said first channel proximate to said spatial location defined by said exit edit point and reproducing on said second recorder audio signals recorded on said second channel proximate to said spatial location defined by said entry edit point, and

(ii) coupling output signals from both recorders to provide an audible display and automatically switching from the output signal from the first recorder to that from the second recorder upon command of an edit signal derived from the stored representations of said exit and entry edit points, and

(f) completing a desired edited composite by repeating said synchronous playing of signals from said first and second channels on said first and second recorders respectively and automatically switching said first recorder into its record mode upon command of said edit signal to cause digitally recorded signals from said second channel occurring after said entry edit point to be recorded on said first channel following the end of the playing of signals on said first channel as designated by the exit edit point.

9. A method of editing and combining selected portions of digitally encoded audio signals recorded on separate channels of record medium to form a composite audio signal comprising the steps of

(a) recording onto one channel of a first record medium digitally encoded audio signals partitioned in a succession of frames containing a predetermined number of data words representing the digital equivalents of increments of analog audio signals and recording onto another channel of said first medium digitally encoded spatial location identifying signal codes likewise partitioned into a succession of frames of equal length as the audio signal frames, the digital code within each spatial location identifying frame corresponding to a unique audio signal frame recorded on said one channel,

(b) recording onto a one channel of a second record medium digitally encoded audio signals partitioned into a like succession of frames containing the same number of data words and recording onto another channel of said second record medium similarly partitioned frames of digitally encoded spatial location identifying signals each of which identifies the spatial location of a unique audio signal frame recorded on said one channel of the second medium,

(c) iteratively playing on a first digital audio recorder audio signals recorded on said one channel of said first medium and determining in steps of discrete time intervals of decreasing duration a location identifying digital signal which represents an increasingly refined exit edit point corresponding to the end frame of a signal portion to be followed by a signal portion from another recording;

(d) storing said digital signal representing said exit edit point;

(e) iteratively playing on a second digital audio recorder audio signals recorded on said one channel of said second medium and determining in steps of discrete time intervals of decreasing duration a location identifying digital signal which represents an increasingly refined entry edit point corresponding to the beginning frame of a signal portion recorded on said second medium to follow the end of the signal portion recorded on the first medium coresponding to the exit edit point;

(f) storing said digital code identifying said entry edit point;

(g) previewing a proposed edited composite signal by

(i) synchronously playing on said first and second recorders audio signals recorded on and first and second media respectively, and

(ii) coupling output signals from both recorders to provide an audible display and automatically switching from the output signal from the first recorder to that from the second recorder upon command of an edit signal derived from the stored digital codes corresponding to said exit and entry edit points, and

(h) completing a desired edited composite by repeating said synchronous playing of signals from said first and second recorders respectively and automatically switching said first recorder into its record mode upon command of said edit signals to cause digitally recorded signals from said second medium starting with said beginning frame as designated by the entry edit point to be recorded on said first channel of said first medium following the end of the playing of said end frame as designated by the exit edit point.

11. A system for editing and combining selected portions of digitally encoded audio signals recorded on separate record media to form a composite digitally encoded audio signal, comprising

(a) transport means for controllably positioning each of said record media along a respective transport path to enable signals to be recorded on and reproduced from each of said media,

(b) read/write means associated with said transport means for recording or reproducing digitally encoded audio signals and related time code data on or from said record media,

(c) keyboard means for

(i) inputting digital control instructions,

(ii) designating tentative and refined exit and entry edit point words defining the spatial location of selected portions of said digitally recorded audio signals and

(iii) modifying said exit and entry edit point words,

(d) timing means for enabling the spatial location defined by said edit point words to be advanced or delayed in a plurality of discrete time intervals of decreasing duration during repeated shuttling of said media on said transport means and the presenting of audible displays of the audio signals proximate to said edit points to determine refined exit and entry edit point words,

(e) means for storing said edit point words,

(f) means for locating and aligning designated channels at the spatial locations defined by said refined edit point words, and

(g) means for effecting selective transfer of signals reproduced from the respective record media at the spatial locations defined by said refined edit point words to combine said selected portions of digitally encoded audio signals to form a composite signal.

12. A system according to claim 11, further comprising means for presenting an audible preview of a proposed edit contructed from selected portions of audio signals from both of said separate media in which the audible display is merged at the spatial locations defined by said refined edit point words, thereby enabling a further refinement of the edit points by iterative shuttling of both media, modifying the edit point words and again previewing the proposed edit point.

13. A system according to claim 11, wherein said transfer means comprises means for operating on said selected portions of said audio signals to directly record said portions onto another channel of record medium to provide a final edited composite digital audio signal.

14. A system according to claim 11 wherein said transfer means further comprises

means for synchronizing the motion of both media with respect to associated playback transducers such that the refined entry edit point word on one of said channels is sensed immediately following the sensing of the refined exit edit point word on the other of said channels,

means for directly recording onto a channel of record medium at least one said selected portion to provide on a single channel of record medium said composite signal consisting of said both components of said selected portions of digitally recorded audio signals.

15. A system according to claim 11, for editing and combining selected portions of digitally encoded audio signals recorded on one channel of a record medium on another channel of which is recorded a digital signal train representing time code data each segment of which identifies the spatial location of a corresponding segment of digitally encoded audio signal recorded on said another channel, said system further comprising the steps of

means for reproducing digital signals corresponding to said recorded time code data,

means for iteratively operating on said reproduced time code related signals in response to said audible displays to designate selected segments thereof as said tentative and refined exit and entry edit point words,

means for storing said selected segments designated as edit point words,

means for operating under control of said stored selected segments to combine portions of said digitally encoded audio signals to form said composite audio signal, and

means for forming a record of said composite signal on at least one channel of said record medium.

16. A system according to claim 11 for editing and combining selected portions of digitally encoded audio signals partitioned in a succession of frames containing a predetermined number of data words representing the digital equivalents of increments of analog signals, comprising

(a) means for progressively modifying the digital representation of a first predetermined number of frames of digitally encoded audio signals recorded on said at least one record medium preceding and following said exit point word to form a digital fade-out signal in which the digitally encoded audio signal amplitude within said first predetermined number of frames gradually decreases to zero amplitude at the last frame following said exit edit point word,

(b) means for progressively modifying the digital representation of a second predetermined number of frames of digitally encoded audio signals recorded on said record medium preceding and following said entry edit point word to form a digital fade-in signal in which the digitally encoded audio signal amplitude within said second predetermined number of frames gradually increases from zero amplitude at the first frame preceding said entry edit point word to its original digital state at the last frame following said entry edit point word,

(c) means for electrically summing in real time said digital fade-out and fade-in signals to provide a composite digital cross-fade signal of relatively constant equivalent amplitude, which at the first frame of the first predetermined number of frames preceding said exit edit point word is wholly derived from the first set of audio signals and which at the last frame of the second number of predetermined frames following said entry edit point word is wholly derived from the second set of audio signals, and

(d) means for recording onto a record medium digital signals derived from said first set of signals ending with the frame immediately preceding the first frame of said first predetermined number of frames, recording thereafter said cross-fade signal and recording after said cross-fade signal signals derived from said second set of signals beginning with the frame immediately following the last of the second number of predetermined frames following said entry edit point word.