WO1994011991A1 - Format de bande magnetique permettant l'enregistrement de signaux audio-video et audio numeriques - Google Patents

Format de bande magnetique permettant l'enregistrement de signaux audio-video et audio numeriques Download PDF

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Publication number
WO1994011991A1
WO1994011991A1 PCT/US1993/011098 US9311098W WO9411991A1 WO 1994011991 A1 WO1994011991 A1 WO 1994011991A1 US 9311098 W US9311098 W US 9311098W WO 9411991 A1 WO9411991 A1 WO 9411991A1
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WO
WIPO (PCT)
Prior art keywords
track
segment
field
video
recording
Prior art date
Application number
PCT/US1993/011098
Other languages
English (en)
Inventor
Steven L. Magnusson
Eric F. Morrison
Ross M. Thomas
George R. Varian
Original Assignee
Ampex Systems Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ampex Systems Corporation filed Critical Ampex Systems Corporation
Publication of WO1994011991A1 publication Critical patent/WO1994011991A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/76—Television signal recording
    • H04N5/91—Television signal processing therefor
    • H04N5/92—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback
    • H04N5/926—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback by pulse code modulation
    • H04N5/9265—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback by pulse code modulation with processing of the sound signal
    • H04N5/9267—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback by pulse code modulation with processing of the sound signal using time division multiplex of the PCM audio and PCM video signals
    • H04N5/9268—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback by pulse code modulation with processing of the sound signal using time division multiplex of the PCM audio and PCM video signals with insertion of the PCM audio signals in the vertical blanking interval of the PCM video signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/76—Television signal recording
    • H04N5/78—Television signal recording using magnetic recording
    • H04N5/782—Television signal recording using magnetic recording on tape
    • H04N5/7824—Television signal recording using magnetic recording on tape with rotating magnetic heads
    • H04N5/7826—Television signal recording using magnetic recording on tape with rotating magnetic heads involving helical scanning of the magnetic tape
    • H04N5/78263—Television signal recording using magnetic recording on tape with rotating magnetic heads involving helical scanning of the magnetic tape for recording on tracks inclined relative to the direction of movement of the tape
    • H04N5/78266—Television signal recording using magnetic recording on tape with rotating magnetic heads involving helical scanning of the magnetic tape for recording on tracks inclined relative to the direction of movement of the tape using more than one track for the recording of one television field or frame, i.e. segmented recording

Definitions

  • This invention relates to digital video tape recording and reproducing apparatus and more particularly to a digital helical magnetic tape having a modified format for optimizing the recording of video and ; audio information.
  • Magnetic tape utilized in video tape recording and reproducing apparatus there are certain standard formats for applying the video and audio information on the magnetic tape.
  • Many of the formats apply to what is referred to as helical formats, that is the information is recorded in digital form on magnetic tape by means of a rotary scanner assembly, in which the tape traverses the drum of the scanner at an angle so that the magnetic tracks recorded thereon are recorded at an angle to the lengthwise direction of the tape.
  • These magnetic video tape formats have become known by different names, such as D-l, D-2, etc., with each having a track including digital video data along with digital audio data or information associated with the particular video information.
  • the scanner runs at its normal rotational speed and the longitudinal tape speed is changed to the desired value (usually between -IX and +3X the normal tape speed).
  • the playback heads are mounted on actuators that allow them to: 1) remain on the desired track during each scan even though the path they would normally follow would not match the recorded track angle, and 2) during the relatively long time interval of each scanner rotation when each playback head is not in contact with the tape, the playback heads can be repositioned to recover the next appropriate track.
  • the time interval for each television field (which is 16.683 msec for the 525 line television picture format)
  • the playback heads must recover all sectors that contain the information for a complete television field.
  • Figure 1 shows a prior at D-l helical track format where the aligned rows or tracks show a lower video sector aligned with a plurality of audio sectors, with an intervening edit gap, followed by an upper video sector.
  • the helical track structure for the D-l 525 line format places the audio sectors, designated A0-A3, in the center of the track for protection, but it is important to note that the video information for each field is recorded in 20 one-half track sectors (10 total tracks) but is spread out over 12 tracks (D-l for the 625 line European format has 24 one-half track video sectors, 12 total tracks, spread out over 14 tracks).
  • This 20 half- track sector arrangement is denoted by the bold dashed lines encircling the video sectors, in which the tracks are designated tracks 1 through 12.
  • playback For a given field of video data, playback is commenced with the upper video sectors of tracks 1 and 2, which are designated “start” with an arrow thereon showing the scan direction.
  • the playback head then tracks to the lower video sectors of tracks 3 and 4, through the audio sectors, through the upper video sectors, and then on to the next pair of tracks, in sequence to finish up at the end of the lower video sectors of tracks 11 and 12.
  • Figures 2 and 3 show the more recent D-2 and D-3 525 line picture formats, with bold lines around one field of video data. Both formats have the audio sectors at the opposite ends of the video sector, which is in the middle of each row.
  • the D-2 format of Figure 2 there are six tracks designated 1 through 6, which are played back in pairs; that is, the "start” of the video field is on tracks 1 and 2, and the "end” of the field is on tracks 5 and 6.
  • This format lends itself well to variable play but the audio sectors are at the ends of the tracks and accordingly, during repositioning of the playback heads, certain portions of the audio may be lost.
  • tracks 1 through 6 include one field of video data with playback commencing at "start” tracks 1 and 2, and ending at "end” tracks 5 and 6.
  • a helical track format for a digital television recorder that provides improved protection for the audio data recorded in each helical track, while at the same time allowing the conventional (simple) implementation of variable play operation that does not require extra playback heads /channels nor complex "overscanning" techniques.
  • a magnetic tape having a helical track format
  • an automatic scan tracking video tape recording and reproducing apparatus utilizing a rotary scanner assembly in which the audio sectors are protected in a track by placement between and in alignment with a pair of video sectors.
  • a field of video data is contained within one or more full track pairs of adjacent tracks for enabling playback at a speed other than normal playback speed thereby enabling playback head repositioning at the end of each field in a time interval during which the playback head is out of contact with the tape.
  • Figure 1 is a diagrammatic representation of the prior art helical track format, known as the D-l 525 line picture format;
  • Figure 2 is a diagrammatic representation of the prior art helical track format, known as the D-2 525 line picture format;
  • Figure 3 is a diagrammatic representation of the prior art helical track format, known as the D-3 525 line picture format;
  • Figure 4 is a diagrammatic representation of a helical track format in accordance with the invention for a 525 line picture format
  • Figure 5 is a diagrammatic representation of a helical track format in accordance with the invention for a 625 line picture format
  • Figure 6 is an exaggerated diagrammatic plan view of a section of magnetic tape showing a plurality of fields of video data; and
  • Figure 7 is a diagrammatic plan view of a rotary AST scanner assembly showing the magnetic tape of Figure 6 in contact therewith.
  • a helical tape format showing one field of video data, which is comprised of six tracks, designated 1 through 6, wherein each track includes three segments; a lower video sector, followed by an edit gap, followed by a plurality of audio sectors designated A0-A3, followed by an upper video sector.
  • the video and audio sectors in each track are aligned and constitute one full track. This arrangement places the audio data sectors in the middle of the helical track for maximum protection, and ensures that the video data for each television field is contained within the same number of tracks as the total video track length of the field.
  • Figures 4 and 5 show the helical track layout for the 525 and 625 line picture formats, respectively.
  • the audio sectors are located in the middle of each track, and 12 one-half track video sectors (6 total tracks) are contained within 6 tracks 1 through 6 for the 525 line picture format, while 16 one-half track video sectors (8 total tracks) are contained within 8 tracks 1 through 8 for the 625 line picture format.
  • the more critical audio sectors A0-A3 are protected by placement between the half track video sectors, with any given half track video sector being in alignment with another half track video sector.
  • the audio sectors A0-A3 in Figures 5 and 6 have been exaggerated in size for the purposes of illustration.
  • each video sector occupies a distance very close to a half track distance, with the audio sectors occupying a very small portion of the total track length.
  • the term "half track" video sector is to be construed liberally in this regard as approximately a one-half track length.
  • the reproducing speed may be at any speed other than normal speed, such as 0.9X, 2X, 3X, etc., these being nine- tenths of normal, twice normal, three times normal speed, etc., or even backwards.
  • Figure 6 diagrammatically illustrates a plurality of fields of video data, designated Fl, F2, F3, etc., helically recorded on a length of magnetic tape 20, wherein the playback head scan is in the direction of the arrow 21, that is diagonally from lower left toward upper right in alignment with the tracks of each of the fields.
  • the fields are played back alternately, that is in the order Fl, F3, F5, etc.
  • the fields are played back in the order Fl, F4, etc., that is, every third field.
  • variable play the information is not recovered continuously. For example, when running at IX you display field 1, field 2, field 3 . . . this is continuous recovery of information and head repositioning is not a problem. But when operating at 2X, for example, the apparatus speeds the tape up to twice the speed and this is where AST (automatic scan tracking) comes in. At double the speed, the heads would not follow the tracks correctly so this requires a mechanism that can move the playback heads. So upon doubling of the tape speed, field 1 is recovered and field 1 is moved away but the AST mechanism is used to keep the playback head on track. Then the head skips over field 2 completely and jumps to field 3. As discussed for 3X operation, two fields are skipped for each field recovered, the main point being that after a field has been recovered, the head has to be moved or repositioned to recover the next field to be read (not necessarily the next successive field).
  • Figure 7 shows diagrammatically a scanner 30 rotating clockwise as indicated by the arrow 25 thereon with the magnetic tape 20 wrapped thereabout through an angle of about 180 degrees, (between points 28 and 29) .
  • formats such as those shown in Figure 1
  • the information is so arranged on the tape as to render it difficult, during variable play, for the playback head to accurately reposition itself from the end of a field to the beginning of the next field (which as described above, may be two or three fields away).
  • the time (between points 26 and 27) may be in the order of only 400-500 microseconds.
  • point 26 would correspond to the position at the end of the lower video sectors while point 27 would correspond to the beginning of the upper video sector.
  • the playback head would then have to reposition itself to read the start of the upper video sector of the next field. Essentially, this repositioning then takes place in a time proportional to the length of the intervening audio sectors.
  • the length of the audio sectors has also been exaggerated and the audio data only occupies a very small length of the total track length.
  • one track played back takes about 5,000 microseconds, while one revolution of the scanner takes about 10,000 microseconds.
  • the time between points 26 and 27 takes about 400 to 500 microseconds, or about 10% of the track playback time. This equates to the length of the audio sectors A0-A3 being only about 10% or less of the total track length.
  • the end of a field corresponds to point 29, with the start of the next field corresponding to point 28, thus providing about a half revolution of the scanner for repositioning of the playback head, a time corresponding to about 5000 microseconds.
  • This particular problem of the small length of time between end of one field and start of another field applies only to the D-l format; however, with respect to the D-2 and D-3 formats illustrated in Figures 2 and 3, those formats have the problem of the audio being at the end of the tracks, where any mis-positioning of the playback head, or premature positioning of the playback head would result in audibly perceptible silence due to the missed audio signals at the end or beginning of the track.
  • the playback head in the event of erroneous repositioning, the playback head will start reading the lower video sector, at whatever point, it lands, while the audio sectors, placed in the middle, will always be read, whether the head starts moving too soon at the end of the upper video sector, or positions itself too late at the beginning of the lower video sector.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Signal Processing For Digital Recording And Reproducing (AREA)

Abstract

Une bande magnétique présente un format de piste hélicoïdal spécifique pour une utilisation avec un magnétoscope à suivi de balayage automatique qui recourt à un ensemble de balayage rotatif à tête de lecture repositionnable. Dans ce format, les secteurs audio d'un piston sont protégés en étant placés entre, et alignés avec, une paire de segments vidéo. Un champ de données vidéo commence au début d'un segment vidéo donné d'une piste donnée et s'achève à la fin du segment vidéo de cette piste, ce qui permet une lecture à une vitesse autre que la vitesse de lecture normale et le repositionnement de la tête de lecture à la fin de chaque champ, dans un laps de temps pendant lequel cette tête n'est plus en contact avec la bande.
PCT/US1993/011098 1992-11-16 1993-11-16 Format de bande magnetique permettant l'enregistrement de signaux audio-video et audio numeriques WO1994011991A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US97692692A 1992-11-16 1992-11-16
US976,926 1992-11-16

Publications (1)

Publication Number Publication Date
WO1994011991A1 true WO1994011991A1 (fr) 1994-05-26

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996022081A1 (fr) * 1995-01-17 1996-07-25 Omega Pharmaceutical, Incorporated Compositions liquides stables de vitamine c, leurs systemes d'administration, leurs procedes de preparation et d'utilisation

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0051938A1 (fr) * 1980-11-07 1982-05-19 Sony Corporation Dispositif de reproduction de signaux vidéo
EP0081356A1 (fr) * 1981-12-04 1983-06-15 Sony Corporation Appareil de reproduction de signaux vidéo
US4819089A (en) * 1984-06-08 1989-04-04 Sony Corporation Digital video recorder having data distribution among four heads
EP0325256A2 (fr) * 1988-01-22 1989-07-26 Sony Corporation Dispositif pour la reproduction de signaux vidéo numériques
US4855843A (en) * 1983-10-11 1989-08-08 Sony Corporation Digital video recording
EP0336424A2 (fr) * 1988-04-08 1989-10-11 Sony Corporation Appareil de reproduction de signaux de données pour un enregistrement à balayage hélicoidal
EP0352980A2 (fr) * 1988-07-28 1990-01-31 Sony Corporation Contrôle de têtes pour un suivi dynamique de piste pour un magnétoscope
EP0364986A2 (fr) * 1988-10-18 1990-04-25 Sony Corporation Appareil de réproduction de signaux vidéo et audio
EP0371717A2 (fr) * 1988-11-29 1990-06-06 Sony Corporation Dispositif de reproduction de données numériques audio et vidéo
US4933784A (en) * 1988-10-31 1990-06-12 Ampex Corporation Automatic head position tracking system for video signals recorded in a segmented format
EP0407046A1 (fr) * 1989-06-16 1991-01-09 Sony Corporation Procédé et appareil de reproduction d'un signal vidéo numérique
EP0420280A2 (fr) * 1989-09-29 1991-04-03 Sony Corporation Appareil de reproduction de signaux d'information numérique pour reproduire le signal audio numérique à une vitesse de reproduction différente de la vitesse d'enregistrement
EP0508827A2 (fr) * 1991-04-11 1992-10-14 Sony Corporation Dispositif de contrôle de suivi de piste

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0051938A1 (fr) * 1980-11-07 1982-05-19 Sony Corporation Dispositif de reproduction de signaux vidéo
EP0081356A1 (fr) * 1981-12-04 1983-06-15 Sony Corporation Appareil de reproduction de signaux vidéo
US4855843A (en) * 1983-10-11 1989-08-08 Sony Corporation Digital video recording
US4819089A (en) * 1984-06-08 1989-04-04 Sony Corporation Digital video recorder having data distribution among four heads
EP0325256A2 (fr) * 1988-01-22 1989-07-26 Sony Corporation Dispositif pour la reproduction de signaux vidéo numériques
EP0336424A2 (fr) * 1988-04-08 1989-10-11 Sony Corporation Appareil de reproduction de signaux de données pour un enregistrement à balayage hélicoidal
EP0352980A2 (fr) * 1988-07-28 1990-01-31 Sony Corporation Contrôle de têtes pour un suivi dynamique de piste pour un magnétoscope
EP0364986A2 (fr) * 1988-10-18 1990-04-25 Sony Corporation Appareil de réproduction de signaux vidéo et audio
US4933784A (en) * 1988-10-31 1990-06-12 Ampex Corporation Automatic head position tracking system for video signals recorded in a segmented format
EP0371717A2 (fr) * 1988-11-29 1990-06-06 Sony Corporation Dispositif de reproduction de données numériques audio et vidéo
EP0407046A1 (fr) * 1989-06-16 1991-01-09 Sony Corporation Procédé et appareil de reproduction d'un signal vidéo numérique
EP0420280A2 (fr) * 1989-09-29 1991-04-03 Sony Corporation Appareil de reproduction de signaux d'information numérique pour reproduire le signal audio numérique à une vitesse de reproduction différente de la vitesse d'enregistrement
EP0508827A2 (fr) * 1991-04-11 1992-10-14 Sony Corporation Dispositif de contrôle de suivi de piste

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* Cited by examiner, † Cited by third party
Title
HEITMANN J.: "Electrical System Design for the SMPTE D-1 DTTR", SMPTE JOURNAL, vol. 95, no. 12, 30 December 1986 (1986-12-30), SCARSDALE, NY US, pages 1215 - 1221 *
P.LIVINGSTON ET AL: "The D-3 Composite Digital VTR Format", SMPTE JOURNAL, vol. 101, no. 9, 30 September 1992 (1992-09-30), SCARSDALE, NY US, pages 602 - 605, XP000309623 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996022081A1 (fr) * 1995-01-17 1996-07-25 Omega Pharmaceutical, Incorporated Compositions liquides stables de vitamine c, leurs systemes d'administration, leurs procedes de preparation et d'utilisation

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