Method and apparatus for producing an audio magnetic tape recording at high speed from a preselected music library

• US 4,851,931 A
• Filed: 02/24/1989
• Issued: 07/25/1989
• Est. Priority Date: 02/20/1987
• Status: Expired due to Fees

• Current Assignee: 1K Music International Limited
• Original Assignee: 1K Music International Limited
• Inventors: Hanrahan, Steven R., Parker, Lorne A., Kleiner, Julian
• Primary Examiner(s): Canney, Vincent P.
• Application Number:
  US07/314,269
• Time in Patent Office: 151 Days
• Field of Search: 360/15
• US Class Current: 360/15
• CPC Class Codes: G09B 5/04 with audible presentation of the material to be studied sound recording or reproducing G11B
• CPC Class Codes: G11B 20/00007 Time or data compression or expansion audio compression based on psychoacoustics G10L19/00; data processing for reproducing audio data at different playback speeds G10L21/04; video compression H04N19/00; data compression per se H03M7/30
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 2220/2587 Laser Discs; Optical disc using analog recording
• CPC Class Codes: G11B 2220/41 Flat as opposed to hierarchical combination, e.g. library of tapes or discs, CD changer, or groups of record carriers that together store one title
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• 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 27/024 on tapes G11B27/028, G11B27/029 take precedence
• CPC Class Codes: G11B 27/031 Electronic editing of digitised analogue information signals, e.g. audio or video signals
• 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 27/34 Indicating arrangements indicating means incorporated in magazine or cassette G11B23/046 and G11B23/0875; indicating measured values in general G01D
• CPC Class Codes: G11B 5/86 Re-recording, i.e. transcribing information from one magnetisable record carrier on to one or more similar or dissimilar record carriers by varying the order of the information G11B27/029, G11B27/036
• CPC Class Codes: H04N 9/802 involving processing of the sound signal H04N9/806, H04N9/835 take precedence

Abstract

The present invention relates to a novel method and apparatus for taking an analog audio signal, converting the signal into a digital audio signal, and thereafter converting the digital audio signal into a standard bandwidth video signal and thereby substantially compressing it. In this format, it can be placed onto a master video tape from which it can be transferred to a video disk. The present invention further comprises a method and apparatus from which a selected number of recordings on the video disk can be retrieved by playing the video disc in still frame mode to create an analog video signal, converting the analog video signal into a string of digital values, converting the digital audio stream into an analog audio signal and thereafter recording the audio signal onto an audio tape at high speed. This method and apparatus is used as the central technology in a consumer electronic music center wherein a consumer can randomly select a given number of song selected from a music library and thereafter create his or her own customized audio tape in a matter of minutes.

Claims

1. A method for producing a custom audio tape consisting of selections from a prerecorded selection library comprising:

a. creating a selection library from a multiplicity of selections from a multiplicity of master audio tapes in which the audio is recorded in analog signal form by;

(i) supplying each analog audio signal from its respective audio tape wherein the audio input is a signal in the range of 20 Hz to 20 kHz;

(ii) filtering said analog audio signal through a 20 kHz low pass filter to prevent aliasing;

(iii) converting said analog audio signal to a digital audio signal by passing the filtered analog audio signal through an 8 Bit analog to digital converter;

(iv) storing the digital audio signal on a signal storage means;

(v) removing said digital audio signal from said signal storage means and converting said digital audio signal into a standard bandwidth video signal by passing the digital audio signal through a 256 Kbyte video frame buffer and thereafter outputting the signal from the video frame buffer sequentially through an 8 bit digital to analog converter thereby converting the signal into a standard bandwidth video signal which is a compressed audio signal;

(vi) passing the compressed audio signal through a 4.5 MHz low pass filter to remove high frequency components;

(vii) recording the compressed filter audio signal on a videotape recorder;

(viii) repeating steps a. (i) through a. (vii) for each signal from each selection chosen from the multiplicity of master audio tapes;

(ix) mastering the video tapes containing the compressed filtered audio signals onto a video laser disc to create an RS-170A Gray Scale formatted video laser disc wherein each analog audio signal is an RS-170 format video signal, comprising all of the desired selections;

b. selecting a specified subset of audio recordings from the selections on said video laser disc;

c. creating said specified subset of audio recordings from the selections on said video laser disc by;

(i) playing a particular frame from the video laser disc in still frame mode to create an analog video signal;

(ii) passing the analog video signal frame by frame through a video frame buffer to convert said analog video signal into a string of digital values and storing the digital values in a 256 kbyte frame storage buffer and thereafter sending the digital values out its digital port;

(iii) sending the string of digital values through a first in first out buffer to control the output data transfer rate of the digitized compressed audio and to take up any gaps in the digital data stream caused during the frame grabbing process;

(iv) converting the digital audio stream into an analog audio signal by passing the digital audio signals through and 8 bit digital to analog converter;

(v) controlling the data transfer rate during the time a digital signal is sent through the first in first out buffer and during conversion of the digital signal into an analog audio signal and creating a time delay between the two steps to permit the data bits to stabilize prior to leaving the first in first out buffer;

(vi) filtering the analog audio signal through a 160 kHz low pass filter to remove high frequency components;

(vii) recording the analog audio signal onto an audio tape; and

(viii) repeating steps c. (i) through c. (vii) for each signal from each of the desired selections on the specified subset of audio recordings from the selections on said video laser disc.

2. The method in accordance with claim 1 wherein said signal storage means is a computer hard disk.

3. The method in accordance with claim 1 wherein said first in first out buffer receives information at approximately 2.5 Mbyte per second and outputs information at approximately 320 kbyte per second.

4. The method in accordance with claim 1 wherein the recording of the analog audio onto audio tape is performed at approximately 8 times normal speed.

5. The method in accordance with claim 1 wherein selecting a specified subset of audio recordings from the selections on said video laser disc further comprises inputting commands through a user interface means to a central processing unit which controls the processes specified in c. (i) through c. (vii).

6. A method for producing a custom audio tape consisting of selections from a prerecorded selection library comprising:

a. creating a selection library from a multiplicity of selections from a multiplicity of master audio tapes in which the audio is recorded in analog signal form by;

(i) supplying each analog audio signal from its respective audio tape;

(ii) filtering said analog audio signal through a low pass filter to prevent aliasing;

(iii) converting said analog audio signal to a digital audio signal by passing the filtered analog audio signal through an analog to digital converter;

(iv) storing the digital audio signal on a signal storage means;

(v) removing said digital audio signal from said signal storage means and converting said digital audio signal into a standard bandwidth video signal by passing the digital audio signal through a video frame buffer and thereafter outputting the signal from the video frame buffer sequentially through a digital to analog converter thereby converting the signal into a standard bandwidth video signal which is a compressed audio signal;

(vi) passing the compressed audio signal through a low pass filter to remove high frequency components;

(vii) recording the compressed filtered audio signal on a videotape recorder;

(viii) repeating steps a. (i) through a. (vii) for each signal from each selection chosen from the multiplicity of master audio tapes;

(ix) mastering the video tapes containing the compressed filtered audio signals onto a video laser disc to create an RS-170A Gray Scale formatted video laser disc wherein each analog audio signal is an RS-170 format video signal, comprising all of the desired selections;

b. selecting a specified subset of audio recordings from the selections on said video laser disc;

c. creating a specified subset of audio recordings from the selections on said video laser disc by;

(i) playing a particular frame from the video laser disc in still frame mode to create an analog video signal;

(ii) passing the analog video signal frame by frame through a video frame buffer to convert said analog video signal into a string of digital values and storing the digital values in frame storage buffer and thereafter sending the digital values out its digital port;

(iii) sending the string of digital values through a first in first out buffer to control the output data transfer rate of the digitized compressed audio and to take up any gaps in the digital data stream caused during the frame grabbing process;

(iv) converting the digital audio stream into an analog audio signal by passing the digital audio signals through a digital to analog converter;

(v) controlling the data transfer rate during the time a digital signal is sent through the first in first out buffer and during conversion of the digital signal into an analog audio signal and creating a time delay between the two steps to permit the data bits to stabilize prior to leaving the first in first out buffer;

(vi) filtering the analog audio signal through a low pass filter to remove high frequency components;

(vii) recording the analog audio signal onto an audio tape; and

(viii) repeating steps c. (i) through c. (vii) for each signal from each of the desired selections on the specified subset of audio recordings from the selections on said video laser disc.

7. The method in accordance with claim 6 wherein said signal storage means is a computer hard disk.

8. The method in accordance with claim 6 wherein said first in first out buffer receives information at approximately 2.5 Mbyte per second and outputs information at approximately 320 kbyte per second.

9. The method in accordance with claim 6 wherein the recording of the analog audio signal onto audio tape is performed at approximately 8 times normal speed.

10. The method as defined in claim 6 wherein said analog audio signal from the master audio tape is in a range from 20 Hz to 20 kHz.

11. The method as defined in claim 6 wherein said filtering of the analog audio signal to prevent aliasing is performed through a 20 kHz low pass filter.

12. The method as defined in claim 6 wherein the conversion of said analog audio signal to a digital audio signal in step a. (iii) is performed through an 8 Bit analog to digital converter.

13. The method as defined in claim 6 wherein the signal storage means used is a computer hard disk.

14. The method as defined in claim 6 wherein the digital audio signal is converted into a compressed audio signal by passage through a video frame buffer and then through and 8-bit digital to analog converter.

15. The method as defined in claim 6 wherein the filtering of the compressed audio signal in step a. (vi) is performed through a 4.5 MHz low pass filter.

16. The method as defined in claim 6 wherein the converting of the digital audio signal into an analog audio signal in step c. (iv) is performed through an 8-bit deglitched digital to analog module.

17. The method as defined in claim 6 wherein the step of filtering the analog audio signal to remove high frequency components in step c. (vi) is performed through a 160 kHz low pass filter.

18. An apparatus for producing an audio magnetic tape recording at high speed consisting of selections from a preselected selection library comprising:

a. user interface means to permit a user to select which selections the user wishes to record, further comprising;

(i) a central processing unit means;

(ii) a video monitor means;

(iii) a video adapter means for interconnecting said video monitor means with said central processing unit means;

(iv) a keypad means;

(v) a keypad interface means for interconnecting said keypad means to said central processing unit means;

(vi) printer means;

(vii) printer interface means for interconnecting said printer means with said central processing unit means;

b. a prerecorded selection library comprised of a multiplicity of selections comprising audio signals from master audio tapes which signals have been filterd through a low pass filter to prevent aliasing, converted into a digital audio signal by having been passed through an analog to digital converter and thereafter converted into a standard bandwidth video signal by being passed through a video frame buffer and digital to analog converter to thereby be converter into a standard bandwidth video signal which is a compressed audio signal, subsequently passed through a low pass filter to remove high frequency components, recorded onto a videotape recorder and subsequently mastered onto a video laser disc such that the prerecorded selection library is comprised of compressed audio signals formatted as video signals on a video laser disc;

c. at least one video disc player for playing a particular frame from the video laser disc in still frame mode to create an analog video signal;

d. at least one video frame buffer for converting the analog signal from the at least one video disc player into a string of digital values;

e. at least one first in first out buffer for controlling the input data transfer rate of the digitzed compressed audio and for taking up any gaps in the digital data stream caused during the frame grabbing process;

f. at least one digital to analog converter for converting the digital audio stream into an analog audio signal;

g. an output clock circuit for controlling the data transfer rate during the time the digital audio signal is sent through said first in first out buffer and also through the digital to analog converter to thereby create a time delay between the first in first out buffer and the digital to analog coverter to permit the data bits to stabilize prior to leaving the first in first out buffer;

h. at least one low pass filter for filtering the signal which has been converted into the analog audio signal;

i. an audio tape; and

j. an audio tape recorder for recording the filtered analog audio signal into the audio tape.

19. An apparatus for producing an audio magnetic tape recording at high speed consisting of selections from a preselected selection library comprising:

a. a user interface means to permit a user to select which selections the user wishes to record, further comprising;

(i) a central processing unit means;

(ii) a video monitor means;

(iii) a video adapter means for interconnecting said video monitor means with said central processing unit means;

(iv) a keypad means;

(v) a keypad interface means for interconnecting said keypad means to said central processing unit means;

(vi) printer means;

(vii) printer interface means for interconnecting said printer means with said central processing unit means;

b. a prerecorded selection library comprised of a multiplicity of selections comprising audio signals from master audio tapes which signals have been filtered through a low pass filter to prevent aliasing, converted into a digital audio signal by having been passed through an analog to digital converter and thereafter converted into a standard bandwidth video signal by being passed through a video frame buffer and digital to analog converter to thereby be converter into a standard bandwidth video signal which is a compressed audio signal, subsequently passed through a low pass filter to remove high frequency components, recorded onto a videotape recorder and subsequently mastered onto a video laser disc such that the prerecorded selection library is comprised of compressed audio signals formatted as video signals on a video laser disc;

c. a multiplicity of video disc players for simultaneously playing selected particular frames from the video laser disc in still frame mode to create an analog video signal from each frame played;

d. a multiplicity of video frame buffers wherein a respective video frame buffer is connected to a respective video disc player for converting the analog signal from the video disc player to which it is connected into a string of digital values;

e. a de-multiplexer circuit for selecting a given one of said multiplicity of video disk players for playing a particular frame from the video laser disc;

f. a multiplicity of first in first out buffers wherein a respective first in first out frame buffer is connected to a respective video frame buffer for controlling the input data transfer rate of the digitzed compressed audio and for taking up any gaps in the digital dat stream caused during the frame grabbing process;

g. a multiplicity of analog to digital converters wherein a respective digital to analog converter is connected to a first in first out buffer for converting the digital audio stream from the first in first out buffer into an analog audio signal;

h. an output clock circuit connected to said multiplicity of video frame buffers for controlling the data transfer rate during the time the digital audio signal is sent through each first in first out buffer and also through each digital to analog converter to thereby create a time delay between each first in first out video frame buffer and the respective digital to analog converter to which it is connected to permit the data bits to stabilize prior to leaving each first in first out video frame buffer;

i. a multiplicity of low pass filters wherein a respective low pass filter is connected to a digital to analog converter for filtering the signal from the respective digital to analog converter which has been converted into the analog audio signal;

j. an audio tape; and

k. an audio tape recorder for recording each filtered analog audio signal onto the audio tape.