[191
`United States Patent
`[11]
`4,280,147
`.
`Baldwin
`[45_] Jul. 21, 1981
`
`
`
`4,159,480
`
`6/1979
`
`Tachi .........................
`
`358/4X
`
`Primary Examz'ner—Bernard Konick
`Assistant Examz'ner—Donald McElheny, Jr.
`Attorney, Agent, or Fz'rm—-Laubscher & Laubscher
`
`[57]
`
`ABSTRACT
`
`A method and apparatus are disclosed for assembling
`digital data representing a T. V. picture, including the
`steps of producing digital words representing a line of
`video, producing a digital code indicative of each line of
`video, producing a digital code indicative of the field
`containing the line, combining the digital codes and the
`digital words for each line of video, storing the digital
`words 1ine—by-line until a number of lines at least equal
`in number to the number of lines in a field has been
`stored, and reading out the digital words. One advan-
`tage afforded by the invention is that for fast winding
`during editing, the stored field of video can be made up
`of lines derived from a number of different fields,
`thereby not only reducing the amount of storage re-
`quired, but also speeding up the process.
`
`16 Claims, 11 Drawing Figures
`
`[54] DIGITAL TELEVISION SYSTEM AND
`METHOD
`
`[75]
`
`Inventor:
`
`John L. ‘E. Baldwin, Eastleigh,
`England
`
`[73] Assignee:
`
`Independent Broadcasting Authority,
`London, England
`
`[21] Appl. No.: 9,185
`
`[22] Filed:
`
`Feb. 2, 1979
`
`Foreign Application Priority Data
`[30]
`Feb. 2, 1978 [GB] United Kingdom ............. .. 04326/78
`
`Int. Cl.3 ............................................. .. H04N 5/79
`[51]
`[52] U.S. Cl. .................................... .. 360/10; 358/127;
`360/33
`[58] Field of Search ................. .. 360/9, 10, 14, 32, 33,
`360/38, 40; 358/4,127, 8
`References Cited
`U.S. PATENT DOCUMENTS
`
`[56]
`
`360/9
`Law ............ ..
`360/9
`Law .... ..
`Pandey ................................ 360/9X
`
`
`
`3,541,244
`3,571,502
`4,016,361
`
`11/1970
`3/1971
`4/1977
`
`Video
`Amt/og
`Signal
`
`Code Indicative
`of Each Line
`of Video
`
`0'
`5
`can
`‘ Coding
`Means
`
`.52
`
`Code /II4I‘C‘tII/V6
`_a/' Field of V/'a’e_L,' Auxiliary
`
`Memory
`
`Write
`Address
`Moan:
`
`Combining
`Alarms
`
`. i -
`"law
`- Scan
`Recording
`Mada:
`
`PMC Exhibit 202
`
`Apple v. PM
`|PR2016-0075
`
`Page 1
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`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
`Page 1
`
`

`
`U.S. Patent
`
`Jul. 21, 1981
`
`Sheet 1 of6
`
`4,280,147
`
`
`
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`PMC Exhibit 202
`
`Apple v. PM
`|PR2016-0075
`
`Page
`
`DROP-OU T
`+
`
`‘ERROR
`DETECTOR
`
`
`HORIZONTAL
`
`ADDRESS
`GENERATOR
`
`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
`Page 2
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`

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`U.S. Patent
`
`Jul. 21, 1981
`
`Sheet 2 of6
`
`4,280,147
`
`
`
`
`HOR/ZONTAL
`READ ADDRESS
`GENERATOR
`
`35
`
`
`
`32
`
`PMC Exhibit 202
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`Apple v. PM
`|PR2016-0075
`
`Page
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`
`
` V/DEO
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`
`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
`Page 3
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`

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`U.S. Patent
`
`Ju1.21, 1981
`
`‘Sheet 3 of6
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`4,280,147
`
`POSITION
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`PMC Exhibit 202
`
`Apple v. PM
`|PR2016-0075
`
`Page
`
`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
`Page 4
`
`

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`U.S. Patent
`
`Jul. 21, 1981
`
`Sheet4 of6
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`4,280,147
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`PMC Exhibit 202
`
`Apple v. PM
`|PR2016-0075
`
`Page
`
`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
`Page 5
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`

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`U.S. Patent
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`Jul. 21, 1981
`
`Sheet 5 of6
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`4,280,147
`
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`PMC Exhibit 202
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`Apple v. PM
`|PR2016-0075
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`Page
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`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
`Page 6
`
`

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`U.S. Patent
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`Jul. 21, 1981
`
`Sheet 6 of 6
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`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
`Page 7
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`

`
`1
`
`4,280,147
`
`DIGITAL TELEVISION SYSTEM AND METHOD
`
`BACKGROUND OF THE INVENTION
`
`I0
`
`15
`
`The present invention relates to a method of_ and 5
`apparatus for displaying digitally encoded video signals,
`and preferably for replaying such signals which have
`been recorded on a recording medium and at a speed
`different to that at which the signals have been re-
`corded.
`Although the bulk'of the description is given in rela-
`tion to the replaying of recorded information,
`the
`method and apparatus are equally useful for accepting
`transmitted digitally encoded video signals, say for
`instant replay in slow motion or for accepting one trans-
`mitted broadcast and synchronising that broadcast with
`another transmitter broadcast.
`,
`The most common existing recording medium is mag-
`netic tape and at present there are two types of so called
`“helical scan” recording and playback apparatus for 20
`magnetic tape. The first type utilizes a revolving drum
`of relatively large diameter which in making one revo-
`lution records or plays back one complete field of a
`television picture from magnetic tape entrained on the
`surface of the drum. The information being recorded as 25
`an angled stripe on the tape. The second tape utilizes a
`drum of smaller diameter which revolves at a higher
`speed than the first type. In this case, one complete field
`is recorded on the tape in a number of segments, say 6,
`and for each revolution of thedrum, one of the seg- 30
`ments is played back. The first type will hereinafter be
`called a non-segmental apparatus and the second type, a
`segmental apparatus.
`For non-segmented recorders there is an inevitable
`gap in information lasting several lines which is nor- 35
`mally arranged to occur during field blanking.
`Such a gap would also occur on segmented recorders,
`between segments, if only one head is used. To over-
`come this problem two heads are used, diametrically
`opposite one another, and the tape is wrapped about 40
`190° around the drum causing an overlap during which
`time switching from one head to the other occurs.
`When editing video tape it is often only necessary to
`have a fairly good visual representation of the picture
`recorded on the tape and it is important that the tape 45
`can be run through faster than usual in orderto save
`time. When using non-segmental type apparatus it is
`possible to run the tape through at a fairly rapid rate,
`say 5 or 6 times the normal rate and stillproduce a
`picture which is acceptable for editing purposes.
`Further, if slow motion is required this cannot be
`achieved with a satisfactory picture quality without
`utilizing expensive ancilliary equipment‘.
`SUMMARY OF THE INVENTION
`We have devised a method of and apparatus for re-
`playing video signals which allows more satisfactory
`slow motion pictures to be obtained and which allows
`editing of video tape regardless of whether the playback
`apparatus is of the segmental or non-segmental type. 60
`For the purposes of this specification slow motion is
`where the picture is shown at a speed 3 times or more
`slower than normal.
`'
`The present invention provides a method of assem-
`bling digital data representing a T.V. picture compris-' 65
`ing, producing digital words representing a line of
`video; producing a digital code indicative of each line of
`video; producing a digital code indicative of the field
`
`50
`
`55
`
`2
`containing the line being sampled; combining said digi-
`tal codes and said digital words; storing said digital
`words until a number of lines at least equal in number to
`the number of lines in a field has been stored; and read-
`ing out said digital words.
`The present invention also provides a digital T.V.
`system comprising a line of video; first coding means for
`producing digital words representing the line of video;
`second coding means for producing a digital code indic-
`ative of each line of video; third coding means for pro-
`ducing a digital code indicative of the field containing
`the line being sampled; combining means for combining
`said digital codes and said digital words; memory means
`for storing said digital words representing a number of
`lines at least equal in number to a field of video; and
`read out means for reading out said digital words.
`In one embodiment, the digital words are recorded
`on a magnetic tape before being stored and read out.
`This allows the picture made up of the digital words to
`be shown at a speed different to that at which it was
`recorded.
`
`One advantage of the above method and apparatus is
`that for some purposes, e.g. fast winding during editing,
`the stored field of video can be made up of lines derived
`from a number of different fields which reduces the
`amount of storage required, and speeds up the process.
`BRIEF DESCRIPTION OF THE DRAWING
`
`Features and advantages of the present invention will
`become apparent from the following description of an
`embodiment thereof given by way of example when
`taken in conjunction with the accompanying drawings,
`in which:
`FIG. 1 shows a diagrammatic representation of seg-
`ments of a picture recorded on magnetic tape;
`FIG. 2 shows a block diagram of one part of appara-
`tus for replaying the information on the tape shown in
`FIG. 1;
`FIG. 3 shows a block diagram of another part of the
`apparatus for replaying the information on the tape
`shown in FIG. 1;
`FIG. 4 shows a diagrammatic representation of the
`spatial position of sample points occurring on a small
`part of a television picture;
`"
`FIG. 5 shows the signal format;
`FIG. 6 shows a simple interpolation scheme for turn-
`ing information recovered on one field to that suitable
`for use on another field;
`FIG. 7 shows the interpolation function used in this
`simple scheme;
`FIG. 8, including 8A and 8B, shows a more complex
`interpolation scheme yielding more acceptable results;
`FIG. 9 shows the interpolation function for this more
`complex interpolation scheme; and -
`.
`FIG. 10 is a block diagram of the system of the pres-
`ent invention for processing a T.V. signal.
`DETAILED DESCRIPTION
`
`The embodiment to be described is based on the fact
`that a field or a colour television picture is made up of
`a plurality of lines each of which can be subjected to an
`analogue to digital conversion and then recorded as a
`digital signal. Further, it is possible to identify individ-
`ual lines of each field and to produce a digital signal
`indicative of and exclusive to an individual line.
`In the embodiment, lines of each field of the picture
`are stored in the appropriate part of a memory together
`
`PMC Exhibit 202
`
`Apple v. PM
`|PR2016-0075
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`Page
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`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
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`4,280,147
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`3
`with information regarding the lines stored and these
`lines are then read out in a sequence which has been
`determined will produce a reasonable picture given the
`manner in which the information has been stored.
`The method and apparatus to be described is applica-
`ble to both PAL, NTSC and SECAM derived video
`signals. However, the bulk of the description is given in
`relation to PAL signals. The main difference between
`the method and apparatus for the types of signals is that
`for NTSC signals fewer lines have to be recorded. This
`comes about due to the fact that a PAL signal will
`repeat itself every eight fields whereas a NTSC signal
`will repeat itself every four fields.
`If every line of a PAL signal were recorded until the
`pattern repeated itself, it would be necessary to record
`2500 lines which would require a twelve bit word giv-
`ing 4096 combinations. It is preferable to use three bits
`to identify the eight fields and nine bits to identify lines
`in a field (either 312 or 313). For some applications a
`sequence of 3l2,312,312,3l6 may be better. Normally
`positive identification of position in sequence can only
`be made at about field sync time by comparison of field
`syncs, line syncs and phase alteration. There remains an
`ambiguity between fields l and 5 of a PAL signal as
`they differ only in sub-carrier phase and since this is not
`defined at present the ambiguity cannot be resolved.
`However, the difference is real and for some applica-
`tions arbitrary decisions have to be made and complied
`with for a production sequence e.g. animation on tape.
`For some applications numbering every line is unnec-
`essary and a reduction of the number of bits for identifi-
`cation may be effected. If, for example, once in four lins
`is sufficient then only three hits need to be sent per'line,
`giving 12 in 10 lines. Under these conditions only 10 bits
`total are necessary for the information but the possibil-
`ity of confusing one set of three bits with another has to
`be resolved. One method is to precede the field number-
`ing bits by say a one and each block of three line num-
`bering bits by a zero; this would normally use four bits
`per line. Another method which takes longer to resolve
`unambiguously is to subtract from the last 12 bits re-
`ceived the previous twelve bits. If note is only taken of
`the last twelve bits when the difference is one, the ambi-
`guity may be resolved. By this means positive identifica-
`tion of a line may be achieved with a maximum eight
`lines starting from scratch.
`The difficulties involved using helical scan apparatus
`will be more apparent from the following discussion of
`FIG. 1 which shows, in diagrammatic form a portion of
`magnetic tape with three recording tracks thereon. If
`the tape has been recorded using non-segmental appara-
`tus, each track will contain one complete field of a
`television picture but if it has been recorded using seg-
`mental apparatus, each track will only contain part of a
`field. The angle of the tracks is determined by the rota-
`tional speed of the drum and the speed of the tape. Thus,
`if either or both of the drum or tape speeds is altered,
`the angle of the path which the scanning heads will
`make as they travel over the tape will alter, becoming
`more upright as the relative tape/head speed increases
`and more nearly horizontal with decreasing tape/head
`speed. The result of that only a portion of each track
`will be properly played back if the playback apparatus
`operates at a different speed to the recording apparatus
`as indicated by cross-hatching in_ FIG. 1.
`The preferred method is to record on the tape digital
`signals, preferably of twelve bits, indicating the field
`and individual line. On playback, these signals, together
`
`#3-
`with the digital signals representing the actual video are
`stored and then retrieved from the store at the proper
`time in order to compose a meaningful representation of
`the original picture. As shown inthe system of FIG. 10,
`first coding means 50 produce from the analog video
`signal‘ digital words representing a line of video, and
`second coding means 52 produce a digital code indica-
`tive of each line of video. Third coding means 54 pro-
`duce a digital code indicative of the field containing the
`lines of video being encoded by the second coding
`means. Combining means 56 combine the digital words
`for each line of video. Memory means 58 store the digi-
`tal words representing a number of lines at least equal in
`number to a field of video, and read out means 60 read
`out the digital words. A separate auxiliary memory 62 is
`provided for storing digital codes representing the fields
`of video, and write address means 64 responsive to the
`digital codes representing the lines of video serve to
`write the digital words into the first memory. Helical
`scan recording means 66 record the combined digital
`words and digital codes on magnetic tape 20, and play
`back means 68 replay the recorded words and codes at
`a speed different to the speed of recording. The write
`address means 64 write the digital words into the mem-
`ory means in a first order, and read address generator
`means 70 read the digital words out of the memory in a
`second order different to the first. Details of the sam-
`pling of the analogue signals and the production of a
`digital word for each sampled analogue value is now
`well known in the art and it is not considered necessary
`to describe the method or the apparatus for doing this.
`Turning now to FIG. 2, this shows part of the play-
`back apparatus. On playback, digital signals are picked
`up from a tape 20 and are checked for errors and drop
`outs using a detector 21. The digital signals also go
`through series
`to parallel conversion means
`(not
`shown). When a complete line -has been correctly re-
`ceived, together with its field and line identification
`codes, the digital video information signals are stored in
`a main store 22, via a data highway and terminals 23, in
`this representation, into the plane of the paper using a
`horizontal address generator 24. Simultaneously,
`the
`line identification code is fed via a further data highway
`and terminals 25 to a line address generator 26 which
`provides the memory line address for the video signals.
`Also the field identification code is fed via yet another
`data highway and terminals 28 to an auxiliary store 29 ,
`_ connected to the main store 22 such that the field identi- '
`fication code for the video signals on terminals 23 can
`also be determined. Should a drop-out occur or there be
`any other error in the information, writing into the main
`store 20 is inhibited by a “write inhibit” signal generated
`by the detector -21.
`'
`It is apparent that the recording tracks containing the
`digital signals can be disposed in any convenient rela-
`tionship e.g. angled using a helical scan type apparatus
`or parallel to the edges of the tape using apparatus such
`as disclosed in our copending application Ser. No.
`888,863, now U.S. Pat. No. 4,199,793 of Apr. 22, 1980.
`This comes about due to the fact that only those por-
`tions of the tracks which contain complete lines are
`stored; all others are rejected.
`FIG. 3 shows how the digital signals in the main and
`auxiliary stores are read out and processed to provide a
`field of video. It will be appreciated that the main store
`22 will have associated with it “write” apparatus as
`shown in FIG. 2 and “read” apparatus as shown in FIG.
`3. However, it is preferred to have two main stores and
`
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`4,280,147
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`5
`two auxiliary stores which are used alternately so that
`as one set of a main and auxiliary store is being “writ-
`ten” intothe other set is being “read.” Thus, in FIG. 3
`only as much of the apparatus is shown as is required ‘for
`an understanding of the “read” operation.
`In FIG. 3 another main store 30 is addressed via a
`read-out means in the form of a line address sequencer
`31. The sequencer can operate in one of two ways de-
`pending on how the information is written into the
`memory. One way is for the information to be written
`into the memory such that the sequencer 31 need only
`sequentially address the memory and read out such line
`stored one after another. Alternatively, the information
`may be written into the store sequentially as it is re-
`ceived. In that case, the line address sequencer has to
`scan the line addresses of the information and extract
`the line information in the correct order for composing
`the picture. This will be explained in more detail later.
`The information contained in the store 30 is thus read
`out via terminals 32 and fed to a video processor 33.
`Simultaneously, the auxiliary store 35 is addressed to
`provide the information regarding the field from which
`that line of video being read out via terminals 32 was
`obtained. The field information is also fed to the video
`processor 33. There it is compared with field reference
`data fed to the processor 33 via terminals 36 and indica-
`tive of the field being displayed by the playback appara-
`tus. The processor 33 makes the necessary corrections if
`any, to the signals fed to it from the stores 30, 35 in
`order that the line information from the main store
`looks like information of the desired field and then feeds
`the processed data to further apparatus (not shown) for
`transmitting or displaying the picture.
`The field reference data is generated from local synch
`pulse data derived from the output of a synch pulse
`generator 37.
`Turning now to the detailed operation of the appara-
`tus; there are two distinct modes, namely slow motion
`and fast winding for editing purposes. Slow motion will
`be discussed first.
`.
`Information has been stored on the tape in the form of
`angled tracks and it is assumed, for simplicity that a
`complete field is‘ recorded on one angled track hence
`the apparatus has two heads. For slow motion display,
`the relative tape/head speed is reduced thus on replay
`the scan of the heads on the tape is more nearly horizon-
`tal than are the actual tracks on the tape hence one of
`the two heads only reproduces a portion of the track
`for, say, field 1 e.g. lines 1 to 50 of field one. It is thus
`apparent that the various fields will be reproduced bit
`by bit but eventually each field will be completely re-
`produced.
`The line information is processed as described above
`in relation to FIG. 2 and stored in the main store 22 or
`30 depending on which is being used at that time for
`writing. The line address generator preferably allocates
`the information received the same address as that infor-
`mation will be used to make up the picture e.g. lines 1 to
`50 will be allocated addresses 1 to 50 and lines 201 to
`250 will be allocated addresses 201 to 250 with the
`stores being filled gradually but not sequentially. This
`allows the information to be read out sequentially. As
`described above, in relation to FIG. 3, it is possible to
`write the information in sequentially and read it out in a
`non-sequential manner but a manner such that lines 1 to
`312 appear at the video processes sequentially.
`The signals to be viewed needs to have the correct
`sequence of fields. Under normal operations this is
`
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`achieved by appropriately phasing the video tape re-
`corder. During fast winding or during slow motion this
`is not possible. For slow motion it is not permissible to
`show fields 1 and 2 alternately a number of times before
`going on to fields 3 and 4, again shown alternately, since
`this would result in an oscillation of the moving parts of
`the picture; the required process is to alternate between
`a signal like field 1 and a signal produced from field 1,
`but with the interlace changed; after a number of repeti-
`tions one then passes on to information recovered from
`field 2.
`
`The video processor 33 is used to ensure that, where
`necessary,
`the information to be transmitted or dis-
`played is in the correct form. How this is achieved will
`now be described with reference to FIGS. 4 to 9. The
`description of FIGS. 4 and 5 is equally applicable to
`both fast winding or slow motion.
`For FIGS. 4 to 9 and the description which follows,
`the signal recorded on the tape and representing the
`video signal is assumed to be either;
`(a) a component coding scheme in which the chromi-
`nance and luminance information is carried by separate
`words recorded on tape; or
`(b) a composite signal e.g. PAL, is recorded on tape
`and on replay this is decoded to give component signals
`with separate words carrying the chrominance and
`luminance information.
`It is also assumed that the sample positions are lined
`up vertically, or near vertically below one another
`when one considers a T.V. picture.
`These assumptions may result in a signal in which the
`sample positions repeat every two fields for a PAL
`signal and this is assumed. In FIG. 4 showing the spatial
`position of the sample points for a number of lines con-
`stituting a picture,
`the luminance sample points are
`shown by a cross, the sample of one of the chrominance
`signals e.g. R-Y is shown by circles and the position of
`the other chrominance signal sampling points e.g. B-Y is
`shown by diamonds. For the particular system chosen
`two chrominance words are produced at alternate sites
`of luminance words. Obviously other arrangements
`could be realized in which the chrominance sample sites
`occur less frequently e.g. every fourth luminance site.
`The production of separate chrominance and lumi-
`nous information can be achieved using any suitable
`apparatus e.g. spacial filters. It is thought that such
`apparatus is now well known in the art but further
`information regarding such apparatus can be obtained
`from I.B.A. Technical Review Vol. 8 September~l976.
`The lines are numbered as they would occur in a
`picture and not as they occur in time; lines n-2, n and
`n+2 occur on one field and n—l, n+1 etc., on the
`other field.
`.
`‘
`FIG. 5 shows the signal format recovered from tape,
`after appropriate decoding if composite coding is used,
`in which E1, represents a B-Y chrominance digital word,
`E1 represents a luminance digital word and E, repre-
`sents an R-Y digital chrominance word. It is convenient
`to arrange that chrominance words together with the
`co-sited luminance words are adjacent as shown in the
`figure. These are separated from the next co-sited group
`by the intervening-luminance word.
`By adopting precisely the same format for each line
`of information it will become apparent from the interpo-
`lation which may follow will always interpolate be-
`tween vertically displaced like word and will result in a
`signal of the same format.
`
`PMC Exhibit 202
`
`Apple v. PM
`IPR2016-0075
`
`Page 1
`
`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
`Page 10
`
`

`
`7
`As mentioned above for slow motion, it is necessary
`to repeat field l a number of times and then slow and
`repeat field 2 a number of times, etc. It is apparent,
`however, that field 1 consists of only 312 lines which is
`only one half of a picture. It is necessary therefore for
`the processor 33 to use the information from field 1 to
`provide the matching interlace for field l.
`A method of changing the interlace is shown in FIG.
`6. Assume that field 2 is to be displayed and that field 2
`information stored will constitute lines n—— 1 and n + 1 of 10
`the eventual picture. It is necessary for the interlacing
`field to produce lines n, n+2 etc of the eventual picture
`and this is done using interpolation techniques on the
`information. In this figure information from lines n—l
`and n+1 pass in step to an adder and after addition the
`signal is multiplied by half and may be used as a substi-
`tute for the information on line 11.
`
`5
`
`15
`
`During slow motion on some fields the information is
`used directly and this leaves the vertical resolution
`unimpaired; on the interleaving fields interpolation will
`normally be used. The interpolation function shown in
`FIG. 7 represents these two cases. When an average of
`the two lines n—l and n+1 is used the vertical resolu-
`tion is impaired and this variation of resolution can be
`disturbing.
`The variation of resolution may be decreased by
`using the arrangement shown in FIG. 8(a) where n— l,
`n+1, etc. relate to the field in question and not the
`picture line numbering as before. With this scheme, by
`an appropriate choice of coefficient k, it is possible to
`arrange that the variation is reduced to zero at one
`particular vertical resolution frequency. Unfortunately
`this variation is only zero at the one frequency and it is
`often found that the variation of resolution at other
`frequencies can be disturbing on certain pictures. A
`better compromise can be obtained by impairing the
`vertical resolution at all times when slow motion is in
`use and this may be achieved by “interpolating” the
`lines n——2, n and n+2 of the field in question as shown
`in FIG. 8 (b) and using this in place of line n when
`interpolation is not theoretically required, using the
`FIG. 8(a) scheme when it‘ is required. An appropriate
`choice of coefficients j and k can be used to give accept-
`able results.
`_
`FIG. 9 shows the interpolation function that results
`and this can be considered to be the equivalent of the
`time domain response to a unit impulse.
`The above description has been given in relation to a
`non-segmental apparatus but a segmental apparatus
`would operate in a similar manner. The main difference
`is that the blocks of lines fed to the memory would
`contain a smaller number of lines but eventually each
`field would be stored in the memory.
`Turning now to fast winding for editing purposes, the
`requirements here are quite different to those prevailing
`for slow motion. Whereas the slow motion mode is
`arranged to producea picture of a quality good enough
`for transmission,
`the fast winding mode is only for
`working purposes and hence it is often not even neces-
`sary to have colour. Thus it has been found that the
`video processor can be largely dispensed with in these
`circumstances.
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`As with slow motion, the change in relative tape/-
`head speed means that only portions of the tracks will
`be replayed. For a non-segmental apparatus the speed of 65
`fast winding is not important but for a segmental appa-
`ratus it may be necessary to wind at a specific rate to
`optimise picture quality. The following description will
`
`4,280,147
`
`8
`be given in relation to segmental apparatus. For Euro-
`pean standards T.V. 6 sweeps/field are used and for
`U.S. standard T.V. 5 sweeps/field are used. The follow-
`ing description will be given in relation of a 6 sweep/-
`field apparatus it being readily apparent how 5 sweep/-
`field apparatus would differ.
`Assuming relative tape/head speed of twice normal
`and the first head starts to sweep the beginning of the
`track recorded by the first head, then recording head
`sweep 2,4,6 of field one are missing which will cause
`parts of the eventual picture to be missing. This, of
`itself, may not be disasterous as far as the operator is
`concerned since the missing part or parts of the picture .
`may be unimportant as far as he is concerned. However,
`we have found that winding at seven times normal rate
`will produce an acceptable picture for editing purposes.
`The picture itself is composed of a number of horizontal
`bands with noisy edges but a complete picture is pres-
`ent. The noise comes about adjacent bands which come
`from different fields. In more detail again assume that
`the first head is arranged to start sweeping the middle of
`head sweep one as recorded. The first head will pro-
`duce information from say lines 1 to 40 of field 1; the
`next head will sweep head sweep 2 of field 2 and pro-
`duce lines 41 to 80 of field 2; the next head will sweep
`head sweep 3 of field 3 and produce lines 81 to 120 of
`field 3 etc.
`Thus the memory will contain information for each
`line of the eventual picture but there will be no com-
`plete field, hence the lack of colour and other problems
`but these are not critical for editing purposes.
`Returning to the slow motion mode, it is necessary if
`this is to be transmitted that the slow motion be syn-
`chronised with the existing transmission. This
`is
`achieved using the field reference data applied to the
`video processor 33 and allows the slow motion to be
`mixed with the transmission so as to be indistinguishable
`therefrom by delaying the slow motion by up to one line
`or up to one frame or more.
`The use of the apparatus as a synchroniser is not
`limited to where slow motion is concerned. Any two
`transmissions can be synchronised and the above appa-
`ratus will be quicker than existing apparatus because
`each broadcast will have its individual lines and fields
`identified, hence there is no need to wait for a specific
`point on one broadcast to come around before knowing
`how much delay should be introduced in order to ac- I
`ceptably match the two transmissions.
`I claim:
`1. A method of assembling digital data representing a
`T.V. picture comprising,
`_
`' producing digital words representing a line of video;
`producing a digital code indicative of each line of
`video;
`‘
`producing a digital code indicative of the field con-
`taining the line;
`_ combining said digital codes and said digital words
`for each line of video;
`storing said digital words line by line until a number
`of lines at least equal in number to the number of
`lines in a field has been stored; and
`reading out said digital words.
`2. A method according to claim 1, wherein the digital
`word is split so that the code representing the field is
`stored separately from said digital words, the digital
`code representing the line being used as the address for
`the stored digital words.
`
`PMC Exhibit 202
`
`Apple v. PM
`IPR2016-0075
`
`Page 11
`
`PMC Exhibit 2024
`Apple v. PMC
`IPR2016-00753
`Page 11
`
`

`
`10
`means for producing a digital code indicative of the
`field containing the lines of video being encoded by said
`se