Method and apparatus for digital video signal processing

• US 4,392,159 A
• Filed: 02/01/1980
• Issued: 07/05/1983
• Est. Priority Date: 02/01/1980
• Status: Expired due to Term

• Current Assignee: Ampex Corporation (Delta Information Systems, Inc.)
• Original Assignee: Ampex Corporation (Delta Information Systems, Inc.)
• Inventors: Lemoine, Maurice G., Pasdera, Leonard A.
• Primary Examiner(s): Faber, Alan
• Application Number:
  US06/117,428
• Time in Patent Office: 1,250 Days
• Field of Search: 358/127, 358/134, 358/4, 358/8, 358/147, 358/12, 358/17, 358/141, 358/148, 358/138, 358/13, 358/150, 358/310, 358/319, 358/335, 358/320, 360/33, 360/32, 360/9, 360/84, 360/37, 360/8, 360/9.1, 360/33.1, 360/37.1, 360/36.2, 375/112
• US Class Current: 386/201
• CPC Class Codes: G09B 5/065 Combinations of audio and video presentations, e.g. videotapes, videodiscs, television systems
• CPC Class Codes: G11B 20/1833 by adding special lists or symbols to the coded information G11B20/1806, G11B20/1866 take precedence
• CPC Class Codes: H04N 5/935 Regeneration of digital synchronisation signals
• CPC Class Codes: H04N 9/808 involving pulse code modulation of the composite colour video-signal
• CPC Class Codes: H04N 9/8722 Regeneration of a colour reference signal, e.g. the colour synchronisaton burst signal, the chrominance signal carrier
• CPC Class Codes: H04N 9/877 by assembling picture element blocks in an intermediate memory

Abstract

A method and apparatus is disclosed for recording and reproducing color television signals on a magnetic media such as magnetic tape, wherein the signals recorded on and reproduced from the magnetic media are in a digital domain. The apparatus utilizes a rotating head wheel having a plurality of transducing heads spaced around its circumference which operate to record and reproduce the digital data transmitted through two separate channels at a very high data rate. The analog color television signal is converted to digital signals in a manner whereby the horizontal blanking interval is compressed and digital synchronizing information is inserted in the compressed horizontal blanking interval for every line. The portion of the real time horizontal blanking interval for which recording is not performed enables time base correction to be accomplished on an individual line by line basis. The digital television signal is processed through memory during recording to enable recording of the data on two channels at a slower than real time rate. During reproducing, the data is again processed through memory and is converted back to real time rate and then converted to an analog signal to which typical synchronizing signals are added.

Claims

1. A method of processing a continuous digital television information signal for recording by a recording apparatus to record said digital television information signal, comprising:

supplying successively occurring increments of said digital television information at a first rate to a plurality of digital memories wherein said memories are arranged in two groups, with each group being associated with a separate information channel;

writing said increments of said digital television information sequentially into selected memories at said first rate so that each increment of said digital television information is written into one of said memories; and

reading increments of digital television information at a second rate that is slower than said first rate simultaneously from selected memories of each group onto said associated information channels such that all of said information in said memories is read thereon, the selected memories being read are other than those into which increments of digital television information are being written.

2. A method of processing a continuous digital television information signal during recording and reproducing operations by a recording and reproducing apparatus, comprising:

during recording, supplying successive increments of said digital television information at a first rate to a plurality of digital memories that are arranged in two groups, with each group being associated with a separate information channel;

during recording, writing said increments of digital television information sequentially into selected ones of said memories at said first rate so that each increment of said information is written into one of said memories;

during recording, reading increments of digital television information in said memories at a second rate that is slower than said first rate such that an increment of said digital information from a selected memory of each group is simultaneously read onto one of two information channels for subsequent digital recording, the selected memories being read are other than those into which increments of digital television information are being written;

during reproducing, simultaneously writing an increment of said digital television information from each of said two information channels into a selected memory of each group at said second rate;

during reproducing, sequentially reading increments of digital television information from said memories at said first rate and combining the same to reconstitute a generally continuous digital television information signal.

3. A method of processing a digital television information signal during recording in a recording apparatus to enable time expanded recording of a generally continuous digital television information signal, comprising:

supplying said digital television information signal to each of four digital memories with first and third memories being associated with a first information channel and second and fourth memories being associated with a second information channel;

writing first and second increments of said digital television information signal into respective first and second memories at a first rate;

writing third and fourth increments of said digital television information signal into respective third and fourth memories at said first rate;

reading said first and second increments from said first and second memories onto separate channels at a second rate slower than said first rate during writing of said third and fourth increments; and

reading said third and fourth increments from said third and fourth memories onto separate channels at said second rate during the writing of said first and second increments thereby providing a time expanded digital video information signal on two channels for recording in a manner whereby none of said memories is simultaneously reading and writing.

4. A method of processing a digital television information signal during a recording operation in a recording apparatus to permit time expanded recording of a generally continuous digital television information signal, comprising:

supplying said digital television information signal to each of four digital memories at a first rate, said digital television information signal being comprised of successively occurring groups of four increments, first and third of said memories being associated with a first information channel and second and fourth memories being associated with a second information channel;

writing first and second increments of each group into respective first and second memories;

writing third and fourth increments of each group into respective third and fourth memories;

reading said first and second increments from said first and second memories at a second rate slower than said first rate onto said respective first and second channels during writing of said third and fourth increments;

and

reading said third and fourth increments from said third and fourth memories at said second rate onto said respective first and second channels during the writing of said first and second increments.

5. A method as defined in claim 4 wherein each of said increments comprises a horizontal line interval of digital television information.

6. A method as defined in claim 4 wherein said first rate is equal to the frequency of the color subcarrier component of a composite analog color television information signal.

7. A method of processing a continuous digital television information signal for recording by a recording apparatus to record said digital television information signal, comprising:

supplying successively occurring increments of said digital television information signal at a first rate to a plurality of digital memories wherein said memories are arranged in two groups, with each group being associated with a separate information channel, each of said increments comprising a horizontal line interval including the horizontal blanking interval and the video interval;

writing a portion of each of said increments of said digital television information signal sequentially into selected memories at said first rate so that said portion of each increment of said digital television information signal is written into one of said memories said portion of said increment being written comprising less than the entire horizontal blanking interval and substantially all of said video interval; and

reading said written portions of said increments of digital television information signal at a second rate that is slower than said first rate simultaneously from selected memories of each group onto said associated information channels such that all of said information is read thereon, the selected memories being read are other than those into which said portions of increments of digital television information signal are being written.

8. A method of processing a continuous digital television information signal during recording and reproducing operations by a recording and reproducing apparatus, comprising:

during recording, supplying successive increments of said digital television information signal at a first rate to a plurality of digital memories that are arranged in two groups, with each group being associated with a separate information channel, each increment of digital television information signal comprising a horizontal line interval including the horizontal blanking interval and a video interval;

during recording, writing a portion of said increments of digital television information signal sequentially into selected ones of said memories at said first rate so that said portion of each increment of said information is written into one of said memories, said portion including all of said video interval and a predetermined amount of said horizontal blanking interval that is less than the entire blanking interval;

during recording, reading said written portion of said increments of digital television information signal at a second rate that is slower than said first rate such that said portion of said increment of said information from a selected memory of each group is simultaneously read onto one of two information channels for subsequent digital recording, the selected memories being read are other than those into which portions of increments of digital television information signal are being written;

during reproducing, simultaneously writing a portion of an increment of said digital television information signal from each of said two information channels into a selected memory of each group at said second rate;

during reproducing, sequentially reading said portions of said increments of said digital television information signal from said memories at said first rate, said reading being delayed for a time period between successive increments that corresponds to the said predetermined amount of said horizontal blanking interval, and combining said increments to reconstitute a generally continuous digital television information signal.

9. A method of processing a continuous digital television information signal comprising successively occurring groups of four increments during reproducing in a reproducing apparatus wherein the digital television information signal has been simultaneously recorded at a second rate on two information channels, said second rate being slower relative to a first rate, said method comprising:

supplying said digital television information signal from each of said channels to two of four digital memories, with the first and third of said memories being associated with a first channel and the second and fourth of said memories being associated with a second channel;

writing a first increment of each group from said first channel into said first memory at said second rate while writing a second increment of each group from said second channel into said second memory;

writing a third increment of each group from said first channel into said third memory while writing a fourth increment of each group from said second channel into said fourth memory;

reading said first increment from said first memory at said first rate followed by reading said second increment from said second memory at said first rate, said reading of said first and second increments occurring during the writing of said third and fourth increments;

reading said third increment from said third memory at said first rate followed by reading said fourth increment from said fourth memory at said first rate, said reading of said third and fourth increments occurring during the writing of said first and second increments; and

sequentially combining said read increments from said memories to reconstitute said continuous digital television information signal at said first rate.

10. In a video recording and reproducing system for processing digital television signals comprising:

first and second sets of digital memories for writing and reading digital television information signals, each of said memories being associated with one of two information channels, each memory being coupled to receive and write input digital television information signals and to read said written signals on to one of said channels during recording, each memory being coupled to receive digital signals from one of said channels during reproducing and write the same therein, and to read the same onto a single output;

control means

coupled to said memories for controlling the writing and reading of said digital television information signals into and out of said memories;

said control means being operable during recording to effect writing of predetermined increments of said digital television information signals into said memories at a first rate and to effect selective reading of said digital television information signals from said memories onto two separate channels at a second slower rate;

said control means being operable during reproducing to effect simultaneous and selective writing of digital television information signals from said two channels into said memories at said second slower rate and to effect selective reading of said digital video signals out of said memories at said first rate;

said control means selectively controlling the reading and writing of said memories so that reading and writing can only occur simultaneously in separate memories.

11. Apparatus as defined in claim 10 wherein each of said increments comprises the digital information for one horizontal video line interval.

12. Apparatus as defined in claim 10 wherein said first rate is equal to the frequency of the color subcarrier frequency of a composite analog television information signal.

13. Apparatus as defined in claim 10 wherein a rotating means has eight transducing heads attached thereto, said heads being equally spaced around the circumference thereof in a common plane that is perpendicular to the axis of said rotating means, for operative association with a record medium, at least two transducing heads being always positioned for operative association with said medium during rotation of said rotating means, one of said two heads coupled to one of said channels and the other of said two heads coupled to said other of said channels.

14. Apparatus as defined in claim 13 wherein one set of four heads is associated with said first channel and another set of four heads being associated with said second channel, the heads of one set being disposed alternately with respect to the heads of the other set around the circumference of said rotating means.

15. Apparatus for recording television information signals on a record medium using a rotating means carrying a plurality of transducing heads and for reproducing recorded television information signals from the record medium, comprising:

means for removing information during the horizontal blanking interval of each horizontal line interval from an input analog composite color television signal having a color burst and color subcarrier component;

means for sampling the analog television signal and converting said samples to digital words;

means for inserting line data during a portion of said horizontal blanking interval of each horizontal line interval, including a sequence of synchronizing digital words, said line data identifying at least the field and color frame of a multi-field sequence in which said horizontal line interval is located and providing timing information relative to the color subcarrier signal component of said television signal, said line data having a time duration less than the duration of the horizontal blanking interval;

digital memory means for receiving and writing into storage said digital words and line data at a first clock rate, said memory means reading said digital words and line data from storage onto at least two separate channels at a second clock rate;

means for applying said digital words and said line data to said transducing heads for recording on said medium;

and,

means for reproducing said digital words and line data from said media and for applying said digital words at least a portion of said line data to said memory means at said second clock rate, said memory means providing said digital words and said portions of said synchronizing digital word sequence at said first rate in a manner whereby said digital words are recombined in their original order.

16. Apparatus as defined in claim 15 further comprising means for converting said digital words to an analog signal, and means for inserting horizontal synchronizing pulses, vertical synchronizing pulses and color burst synchronizing signals in said converted analog signal at blanking interval locations therein.

17. Apparatus as defined in claim 15 wherein said line data inserting means inserts digital data identifying the number of each horizontal line interval in a full multi-field color sequence as part of said line data.

18. Apparatus as defined in claim 15 wherein said multi-field color sequence comprises a four field sequence in the NTSC television signal format.

19. Apparatus as defined in claim 15 wherein said sequence of synchronizing digital words comprises a predetermined number of identical digital words.

20. Apparatus for processing a digital television signal for transmission through a digital data transmission channel, said television signal including horizontal blanking intervals defining line intervals of video data, comprising:

means for inserting digital synchronizing information in place of each horizontal blanking interval to be transmitted through the digital data transmission channel, said synchronizing information defining the beginning of the video data portion of said each line and having a time duration less than the duration of the horizontal blanking interval, the inserted digital synchronizing information and video data portions forming a processed television signal; and

,

means for coupling said processed television signal to said data transmission channel for transmission therethrough.

21. The apparatus as defined in claim 20 wherein the coupling means includes:

memory means for storing the processed television signal, said memory means having an input coupled to receive the processed television signal and an output coupled to the data transmission channel;

first control means coupled to the memory means for initiating and effecting the writing into storage at a first rate of the processed television signal received at the input, the first control means initiating the writing of each line of the received processed television signal at a time corresponding to the occurrence of the digital synchronizing information in the line; and

second control means coupled to said memory means to effect reading of said stored processed television signal from the memory means to the output at a second rate that is slower than said first rate.

22. The apparatus as defined in claim 21 wherein the second rate is slower than the first rate by an amount proportional to the difference between the duration of the line interval of the television signal and the duration of the interval formed by said digital synchronizing information and video data portion associated with said line interval.

23. The apparatus as defined in claim 21 wherein:

the data transmission channel includes a plurality of N signal channels and a recording apparatus for recording the processed television signal transmitted through said signal channels, said recording apparatus having a plurality of signal transducers rotated in operative association with a record medium so that at least N signal transducers of said plurality of signal transducers are always positioned for operative association with said record medium, as said plurality of signal transducers are rotated, each of the N signal channels coupled to one of the N signal transducers in operative association with the record medium; and

,

the second rate is slower than the first rate by an amount proportional to 1/N and the difference between the duration of the line interval of the television signal and the duration of the interval formed by the digital synchronizing information and video data portion associated with said line interval.

24. The apparatus as defined in claim 23 wherein:

said apparatus has a data transmission operating mode and a data receiving operating mode;

the memory means has a data input and a data output;

the first control means is responsive to the apparatus being in a data transmission operating mode to couple the data input of said memory means to the inserting means for receiving the processed television signal provided thereby and to initiate and effect the writing into storage of each line of the received processed television signal at a time corresponding to the occurrence of the digital synchronizing information in the line interval;

the first control means is responsive to the apparatus being in a data receiving operating mode to couple the input of the memory means to the data transmission channel for receiving the processed television signal therefrom and is responsive to the occurrence of the digital synchronizing information in each line interval of the received processed television signal to initiate and effect the writing into storage of said each line interval;

the second control means is responsive to the apparatus being in a data transmission operating mode to couple the output of the memory means to the data transmission channel and to effect the reading of the stored processed television signal from the memory means to the data transmission channel; and

the second control means is responsive to the apparatus being in a data receiving operating mode to couple the output of the memory means to a data utilizing means and is responsive to the reference timing signal to effect the reading of the stored processed television signal from the memory means to the data utilizing means.

25. The apparatus as defined in claim 24 wherein:

the first control means is responsive to the apparatus being in a data transmission operating mode to effect writing into storage at a first rate of the processed television signal received from the inserting means;

the first control means is responsive to the apparatus being in a data receiving operating mode to effect writing into storage at a second rate of the processed television signal received from the data transmission channel;

the second control means is responsive to the apparatus being in a data transmission operating mode to effect the reading of the stored processed television signal from the memory means at said second rate;

the second control means is responsive to the apparatus being in a data receiving operating mode to effect the reading of the stored processed television signal from the memory means at said first rate; and

the second rate is slower than the first rate by an amount proportional to the difference between the duration of the line interval of the television signal and the duration of the interval formed by the digital synchronizing information and video data portion associated with said line interval.

26. The apparatus as defined in claim 20 adapted for processing the processed television signal following transmission through the data transmission channel, further comprising:

memory means coupled to receive and store the processed television signal from the data transmission channel;

first control means coupled to said memory means and responsive to the occurrence of the digital synchronizing information in each line interval of the received processed television signal to initiate and effect the writing of said processed television signal into the memory means for storage therein; and

second control means coupled to said memory means and responsive to a reference timing signal to effect the reading of said stored processed television signal from the memory means.

27. The apparatus as defined in claim 26 wherein:

the memory means is a randomly addressable digital store having address storage locations for receiving and storing successive intervals of the processed digital television signal received from the data transmission channel at different addressed storage locations of the digital stores;

the first control means is responsive to the occurrence of the digital synchronizing information in each line interval of the received processed digital television signal to effect the writing into storage of the successive intervals of the processed digital television signal at times determined by a clock signal coherent with the received processed digital television signal; and

the second control means is responsive to the reference timing signal to effect reading of the stored processed digital television signal from storage at times determined by a reference clock signal.

28. The apparatus as defined in claim 27 wherein:

said apparatus has a data transmission operating mode and a data receiving operating mode;

the randomly addressable digital store has a data input and a data output;

the first control means is responsive to the apparatus being in a data transmission operating mode to couple the data input of said randomly addressable digital store to the inserting means for receiving the processed television signal provided thereby and to initiate and effect the writing into storage of each line of the received processed television signal upon the occurrence of the digital synchronizing information in the line interval and at times determined by a clock signal coherent with the received processed digital television signal;

the first control means is responsive to the apparatus being in a data receiving operating mode to couple the input of the randomly addressable digital store to the data transmission channel for receiving and storing the processed television signal;

the second control means is responsive to the apparatus being in a data transmission operating mode to couple the output of the randomly addressable digital store to the data transmission channel and to effect the reading of the stored processed television signal from said store to the data transmission channel at times determined by a clock signal coherent with the transmitted processed television signal; and

the second control means is responsive to the apparatus being in a data receiving operating mode to couple the output of the randomly addressable digital store to a data utilizing means for reading the stored processed television signal.

29. Apparatus for processing a digital information signal for transmission through a data transmission channel, said information signal including periodically occurring synchronizing intervals defining intervals of information, comprising:

means for inserting digital synchronizing information in place of each synchronizing interval to be transmitted through the data transmission channel, said synchronizing information defining the beginning of each information interval and having a time duration less than the duration of the periodically occurring synchronizing interval, the inserted digital synchronizing information and information interval forming a processed signal; and

,

means for coupling said processed signal to said data transmission channel for transmission therethrough.

30. The apparatus as defined in claim 29 adapted for processing the processed signal following transmission through the data transmission channel, further comprising:

memory means coupled to receive and store the processed signal from the data transmission channel;

first control means coupled to said memory means and responsive to the occurrence of the digital synchronizing information preceding each information interval of the received processed signal to initiate and effect the writing of said processed signal into the memory means for storage therein;

and

second control means coupled to said memory means and responsive to a reference timing signal to effect the reading of said stored processed signal from the memory means.

31. The apparatus as defined in claim 30 wherein:

said apparatus has a data transmission operating mode and a data receiving operating mode;

the memory means has a data input and a data output;

the first control means is responsive to the apparatus being in a data transmission operating mode to couple the data input of said memory means to the inserting means for receiving the processed signal provided thereby and to initiate and effect the writing into storage of each interval of the received processed signal at a time corresponding to the occurrence of the digital synchronizing information of the interval;

the first control means is responsive to the apparatus being in a data receiving operating mode to couple the input of the memory means to the data transmission channel for receiving the processed signal therefrom and is responsive to the occurrence of the digital synchronizing information in each interval of the received processed signal to initiate and effect the writing into storage of said each interval;

the second control means is responsive to the apparatus being in a data transmission operating mode to couple the output of the memory means to the data transmission channel and to effect the reading of the stored processed signal from the memory means to the data transmission channel; and

the second control means is responsive to the apparatus being in a data receiving operating mode to couple the output of the memory means to a data utilizing means and is responsive to the reference timing signal to effect the reading of the stored processed signal from the memory means to the data utilizing means.