1、 STD-SMPTE 2b5M-ENGL 3778 D 8357403 O003372 333 I CMPTE STANDARD SMPTE 265M-1998 Revision of ANSVSMPTE 265M-1993 for Television 1/2=in Type 625/50 Digital Recording - D-3 Composite Format - Table of contents Page 1 of 42 pages 2 Normative references 1 Scope 2 Normative references 3 Environment and t
2、est conditions 4 Video tape 5 Helical recording 6 Program track data 7 Video interface 8 Audio interface 9 Video processing 1 O Audio processing 11 Longitudinal tracks Annex A Tape tension Annex B Cross-tape track measurement technique Annex C Mathematically processed measured tape data Annex D Trac
3、k pattern during insert editing Annex E Bibliography 1 Scope This standard specifies the content, format, and recording method of the data blocks containing video, audio, and associated data which form the helical recods on 12.65m (0.5in)tapeincassettesasspecifiedinANSVSMPTE263M. In addition, this s
4、tandard specifies the content, format, and recording method of the longitudinal record con- taining tracking infonation for the scanning head associated with the helical records, and also the lon- gitudinal cue audio and time code tracks. One video channel and four independent audio channels are rec
5、orded in the digital format. Each of these channels is designed to be capable of independent editing.The video channel records and reproduces a composite television signal in the 625-line system with a frame frequency of 25 Hz. Figures 1 and 2 show a block diagram of the processes involved in the re
6、corder. The following standards contain provisions which, through reference in this text, constitute provisions of this standard. All standards are subject to revision and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition o
7、f the standards indicated below. SMPTE RP 155-1997, Audio Levels for Digital Audio Records on Digital Television Tape Recorders IEC 60461 (1986-09), Time and Control Code for Video Tape Recorders IEC 611 79 (1 993-03), Helical-Scan Digital Compos- ite Video Cassette Recording System Using 19 mm Magn
8、etic Tape, Format D2 (NTSC, PAL, PAL-M) ITU-R BC.647-2 (1994), A Digital Audio Interface for Broadcasting Studios ITU-R.470-4 (1 994), Television Systems 3 Environment and test conditions 3.1 Environment Tests and measurements made on the system to check the requirements of this standard shall be ca
9、r- ried out under the following conditions: - Temperature (20 f 1)“C - Relative humidity (50 k 2)% - Barometric pressure - Tape conditioning - Center tape tension 86 kPa to 106 kPa not less than 24 h (0.31 I 0.05) N (see annex A) Copyright Q 1998 by THE SOCIEPI OF MOTION PICTURE AND TELEVISION ENGIN
10、EERS 595 W. Hartsdale Ave., White Plailis, NY 10607 (914) 761-1100 Approved December 8,1998 STD-SMPTE 2bSH-ENGL 1998 W 8357901 0003373 258 SMPTE 265M-1998 AUDIO 4 BLOCK - ; ANALOG/ INTRA- OUTER ECC DIGITAL -.* FIELD INTERFACE SHUFFLE CODER SHUFFLE (DIGITAL) - - - VI DEO f A ANALOG/ CHANNEL OUTER INT
11、RA- DIGITAL -b DEMUX -b ECC FIELD CODER SHUFFLE INTERFACE SWITCH (DIGITAL) . . - - - - 7 DATA SYNC/ MUX ID GEN. CODER HELICAL DRIVER TRACK RECORD TIME CODE DRIVERS - - - - - - - - - - REC.AMP (ANALOG) CUEIREF Figure 1 - Record block diagram AUDIO BLOCK DESHUFFLE FIELD (ANALOG) *- DIGITAL/ AUDIO ANAL
12、OG + ERROR *- (DIGITAL) CHANNEL OUTER INTRA- ECC + FIELD DECODER DESHUFF LE 4 CONTROL TRACK TRACK P.E. y - - - - - I_ - - HEADS AND - TIME CODE 4 PLAY BACK T.C. READER - INTERFACE TIME CODE4 -I- (ANALOG) CUEIREF 4 P.B.AMP Figure 2 - Playback block diagram Page 2 of 42 pages STD-SMPTE 2bSfl-ENGL 1978
13、 I6357401 0003174 17Li M SMPTE 265M-1998 3.2 Reference tape Blank tape for reference recordings should be avail- able from any source meeting the tape characteristics specified by this standard. 3.3 Calibration tapes The calibration tapes meeting the requirements of 3.3.1 and clause 4 should be avai
14、lable from manufac- turers who produce video tape recorders and players in accordance with this Standard. 3.3.1 Record locations and dimensions evaluated by measuring the tape width at 10 points each separated by a distance of 1 O0 mm. 4.4 Reference edge straightness The reference edge straightness
15、maximum deviation is 6 pm peak to peak. Edge straightness fluctuation is measured at the edge of a moving tape guided by three guides having contact to the same edge and having a distance of 85 mm from the first to second guide and 85 mm from the second to third guide. Edge measurements are averaged
16、 over 1 O-mm lengths and are made 5 mm from the midpoint between the first and second guide, toward the first guide. The tolerances shown in table 1 shall be reduced by 50%. 4.5 Tape thickness 3.3.2 Calibration signals Two types of signals shall be recorded on the calibra- tion tape: (a) - Video: 10
17、0% color bars; - Audio: l-kHz tone at -20 dB below full level; - Cue: l-kHz tone at reference level; 10-kHz tone at reference level. (b) A signal of constant recorded frequency (i.e., one- half the Nyquist frequency) only with tracks of field O, segment O for the purpose of mechanical alignment. 4 V
18、ideo tape 4.1 Base The base material shall be polyester or equivalent. The thickness of the tape (including all coatings) shall be 10.2 pm to 11 .O pm and 13.0 pm to 14.0 pm, recpectively. 4.6 Transmissivity Transmissivity shall be less than 5%, measured over the range of wavelengths 800 nm to 900 n
19、m. 4.7 Offset yield strength The offset yield strength shall be greater than 9 N for 11 pm tape and 10 N for 14 pm tape. The force to produce 0.2% tangential elongation of a 1000-mm test sample with a pull rate of 10 mm per minute shall be used to confirm the offset yield strength. The line beginnin
20、g at 0.2% elongation parallel to the initial tangential slope is drawn and then read at the point of intersection of the line and the stress-strain curve. 4.2 Width 4.8 Magnetic coating The tape width shall be 12.650 mm rt 0.008 mm. The tape, covered with glass, is measured without tension at a mini
21、mum of five different positions along the tape using a calibrated comparator having an accuracy of 1/1000 mm = 1 pm. The tape width is defined as the average of the five readings. 4.3 Width fluctuation Tape width fluctuation shall not exceed 5 pm peak to peak. Measurement of tape width fluctuation s
22、hall be over a tape length of 900 mm at the beginning of tape winding. The value of tape width fluctuation shall be The magnetic tape used shall have a coating of metal particles or equivalent. 4.9 Coating coercivity Thecoatingcoercivityshall beaclass 1600 (1273OOAlm), with an applied field of 5000
23、Oe as measured by a 50- or WHz BH meter or vibrating sample magnetometer (VSM). 4.10 Particle orientation The metal particles shall be longitudinally oriented. Page 3 of 42 pages Table 1 - Record location and dimensions Mi II imeters Dimensions Nominal Tolerance A B C D E F G H I K L Mi M P1 P2 W XI
24、 x2 x3 x4 x5 Y 9 a0 a1 Time code track lower edge Time code track upper edge Control track lower edge Control track upper edge Program area lower edge Program area width Cue audio track lower edge Cue audio track upper edge Helical track pitch Video sector length Helical track total length Audio sec
25、tor 1 length ) Audio sector 2-4 length *) Control reference pulse to program reference point (see figure 22) Cue/time code signal (bit No. O) to program reference point Tape width Location of start of video sector Location of start of audio sector A4 3, Location of start of audio sector A2 3, Locati
26、on of start of audio sector A3 3, Location of start of audio sector Ai 3, Program area reference Track angle 4.91 73“ basic Azimuth anale (track 1) Azimuth angle (track O) -20.017 f 0.150 19.983 f 0.150“ O 0.450 0.900 1.300 1.573 10.090 11.950 12.550 0.0180 108.898 117.713 1.902 1.828 176.900 178.60
27、0 12.650 O 11 1.441 109.256 2.185 4.370 1.960 Basic 10.050 k 0.050 f 0.050 Derived Derived I0.050 f 0.050 Ref Derived Derived Derived Derived f 0.050 f 0.100 f 0.008 f 0.050 f 0.050 f 0.050 f 0.050 f 0.050 Basic I. ) Audio sectors located at the start of helical tracks. 3, Audio channel numbers vary
28、 (see 10.9). All other audio sectors. NOTE - Measurements shall be made under the conditions specified in 3.1. The measurements shall be corrected to account for actual tape speed (see figures B.l and B.2). 5 Helical recording 5.1 Tape speed The tape speed shall be 83.880 mds; the tolerance shall be
29、 k 0.2 %. 5.2 Record location and dimensions 5.2.1 The format requires a full-width erase head for continuous recording and a flying erase head for insert editing. 5.2.2 Record location and dimensions for continu- ous recording shall be as specified in figures 3 and 4 and table 1. In recording, sect
30、or locations on each helical track shall be contained within the tolerance specified in table 1 and figure 3. 5.2.3 The reference edge of the tape for dimen- sions specified in this standard shall be the lower edge as shown in figure 3. The magnetic coating, with the direction of tape travel as show
31、n in figure 3, is on the side facing the observer. (Measuring techniques are shown in annexes B and C.) Page 4 of 42 pages STD-SMPTE ZLSM-ENGL 1998 8357403 0003L7b Tb7 0 SMPTE 265M-1998 DIRECTION OF TAPE TRAVEL * REFERENCE EDGE DETAILS OF A NOTES 1 AI, A2, A3, and A4 are audio sectors. 2 TO and TI a
32、re track numbers; SO is a segment number (typical). The track number is identified by the azimuth angle. 3 Tape viewed from magnetic coating side. 4 Dimensions Xl-X5 are determined by the program reference point as defined in figure 4. Figure 3 - Location and dimensions of recorded tracks Page 5 of
33、42 pages STD-SMPTE 2bSM-ENGL I998 8357403 0003377 9T3 9 SMPTE 265M-1998 1.CONTROL TRACK RECORD 2 I i HEAD MOTION i iA c w TAPE TRAVEL - PROGRAM REFERENCE PO I NT START OF PROGRAM REFERENCE PO I NT DETAIL C SERVO REFERENCE PULSE f RECORDING-CURRENT WAVEFORM CONTROL IN-S IS-N 1 I MAGNETIZATION ON THE
34、TAPE DETAIL A zu: REFERENCE EDGE TRACK DETAIL B 2. CUE/TIME CODE RECORD D3 CUE TRACK TAPE TRAVEL 7 - UTIME CODE TRACK B Figure 4 - Location of cue, time code and control track record Page 6 of 42 pages STD-SMPTE 2b5M-ENGL 1998 = 8357q01 0003178 83T m 52.4 As indicated in figure 3, this standard anti
35、cipates a zero guard band between recorded tracks, and the record head width should be equivalent to the track pitch of 18 pm. The scanner head configuration should be cho- sen such that the recorded track widths are con- tained within the limits of 16 ym to 20 ym. 5.2.5 In insert editing, this stan
36、dard provides a guard band of 2 pm (nominal) between the previously recorded track and the inserted track at editing points only. A typical track pattern for insert editing is shown in figure D.1. 5.3 Helical track record tolerance zones 5.3.1 The lower edges of any four consecutive tracks starting
37、at the first track in each video frame shall be contained within the pattern of the four tolerance zones established in figure 5. Each zone is defined by two parallel lines which are inclined at an angle of 4.9173 basic with respect to the tape reference edge. 5.3.2 The centerlines of all zones shal
38、l be spaced apart 0.0180 mm basic. The width of zones 1, 3, and 4 shall be 0.006 mm basic. The width of zone 2 shall be 0.004 mm basic. These zones are established to contain track angle errors, track straightness errors, and vertical. head offset tolerance. (Measuring techniques are shown in annexe
39、s 6 and C.) 5.4 Relative positions of recorded tracks 5.4.1 Relative positions of longitudinal tracks Audio, video, ancillary data, control track, time code, and cue track with information intended to be time coincident shall be positioned as shown in figures 3 and 4. 5.4.2 Helicacontrol track relat
40、ionship The spatial relationship among the cue track record, time code record, control track record, and helical tracks is specified in figures 3 and 4. 5.4.3 Program area reference point The program area reference point is determined by the intersection of a line parallel to the reference edge of t
41、he SMPTE 265M-1998 tape at a distance Y from the reference edge and the centerline of the first track in each video field (segment O, track O). The end of the preamble and the start of the video sector shall be recorded at the program area reference point, and the tolerance is dimension X1. The loca
42、- tions are shown in figures 3 and 4; dimensions X1 and Y are specified in table 1. The relationship between sectors and contents of each sector is specified in clause 6. 5.5 Gap azimuth 5.5.1 Cue track, control track, time code track The azimuth angle of the cue, control track, and time code head g
43、aps used to produce longitudinal track records shall be perpendicular to the track record. 5.5.2 Helical track The azimuth of the head gaps used for the helical track recording shall be inclined at angles ao and ai as specified in table 1 to the perpendicular to the helical track record. The azimuth
44、 of the first track of every field (segment O, track O) shall be oriented in a counterclockwise direction with respect to the line perpendicular to the track direction when viewed from the side of the tape containing the magnetic record. 5.6 Transport and scanner The effective drum diameter, tape te
45、nsion, helix angle, and tape speed taken together determine the track angle. Different methods of design and/or variations in drum diameter and tape tension can produce equivalent recordings for interchange purposes. One possible configuration of the transport uses a scanner with an effective diamet
46、er of 76.000 mm. Scan- ner rotation is in the same direction as tape motion during normal playback mode. Data is recorded by two head pairs mounted at 180“ angles from each other. Figure 6 shows one possible mechanical configuration of the scanner and table 2 shows the corresponding mechanical param
47、eters. Figure 7 shows the relationship between the longitudinal heads and the scanner. Other mechanical configurations are allowable pro- vided the same footprint of recorded information is produced on tape. Erase heads are described in 5.2.1 and figure 6. Page 7 of 42 pages STD-%SMPTE 2b5M-ENGL 379
48、8 m 8357401 0003377 77b SMPTE 265M-1998 1, I I - i i I TRACK LOWER EDGES CENTER DRUM LOWER DRUM Figure 5 - Location and dimensions of tolerance zones of helical track record H5-H6 : FLY I NG ERASE HEAD HI-H4:RECORDING HEAD TIPS I (INSERT EDITING ONLY) 76.000 mm (NOMINAL) DRUM DI AMETER I ! I I j O.
49、0434 1 UPPER DRUM O. 0 166 i Figure 6 - A possible scanner configuration Page 8 of 42 pages SMPTE 2651-1998 WRAP EFFECTIVE POLE TIP ROTAT I ON TAPE TRAVEL TOP VIEW PROGRAM 176. 90 NOTE - Unwrapped, viewed magnetic coating side. Figure 7 - A possible longitudinal head location and tape wrap Page 9 of 42 pages STD-SMPTE 2bSM-ENGL CMPTE 265M-1998 Table 2 - Parameters for a possible scanner design Parameters Scanner rotation speed (rpc) Number of tracks pe
