SMPTE ST 137-2000 Motion-Picture Film (35-mm) - Release Prints - Four Magnetic Audio Records.pdf

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1、STD-SMPTE 137-ENGL 2000 = 8357401 0004119 199 D SMPTE STANDARD SMPTE 137-2000 Revision of ANCIISMPTE 137-1994 for Motion-Picture Film (35-mm) - Release Prints - Four Magnetic Audio Records Page 1 of 2 pages 1 Scope 1.1 This standard specifies the position, dimen- sions, reproducing speed, identity,

2、and use of the four magnetic audio records on 35-mm motion-picture release prints. 1.2 The standard also specifies the longitudinal picture-audio displacement on the film. 2 Audio records 2.1 The lateral location and width of the mag- netic audio records shall be as specified in figure 1 and table 1

3、. 2.1.1 The records shall be referred to by number, as shown in figure 1, with record No. 1 nearest the reference edge. The left and right channel apply to a listener facing the screen. Record No. 1 shall be used for the left loudspeaker channel. Record No. 2 shall be used for the center loud- speak

4、er channel. Record No. 3 shall be used for the right loudspeaker channel. Record No. 4 shall be used for the surround or auditorium loudspeakers or control signals or both. 2.2 The recording shall be made so that the azimuth of the record is at an angle of 90 15 to the reference edge of the film. 2.

5、3 With the direction of film travel as shown in figure 1, the magnetic striping shall be on the surface of the film facing the projector lens. 2.4 The audio records shall be recorded in such a manner that they can be reproduced properly by reproducing heads whose gaps are posi- tioned along a common

6、 plane and in line. - REFERENCE EDGE FILM TRAVEL 1 Figure 1 - Magnetic audio records Table 1 - Specifications Dimensions Inches Mi II imet ers A 0.040 f 0.002 1.02 f 0.05 B 0.171 f 0.002 4.34 f 0.05 C 1.148 I 0.002 29.16 I 0.05 D 1.298 I 0.002 32.97 f 0.05 E 0.059 min 1.50 min F 0.036 f 0.002 0.91 $

7、r 0.05 Copyright O 2000 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Harsdale Ave., White Plains, NY 1W7 (914) 761-1100 Approved May 30,2000 STD.SMPTE L37-ENGL 2000 357403 0004120 700 SMPTE 137-2000 3 Reproducing speed NOTE - The dimensions which locate the reproducing heads are

8、based on the assumtion that the film has shrunk 0.2% in width. Since the shrinkage of the film will normally increase between the time of recording and the time of values should be taken to determine the dimensions which locate the recording and reproducing heads, but the same The recordings shall b

9、e made so that the second (approximately 18 in I457 mm per second) which is 24 frame&. records will reproduce properly at 96 perforations per reproducing, fi would be logical that different shrinkage ft 27 ml per minute Or value of 0.2% (which corresponds to low-shrinkage safety- type film) is adopt

10、ed for practical reasons. This value has been chosen to represent rather more than the shrinkage 4 Longitudinal pictureaudio displacement likely to have occurred at the time of recording and rather less than the shrinkage likely to have occurred at the time of reproducing. The magnetic audio records

11、 on the film shall lag behind the center of the corresponding picture by a distance of 28 frames t l/r! frame (see annex A.5). Annex A (informative) Additional data A.l Recordwldth The width of the recorded area must be measured with great care as it enters directly into the calculation of flux per

12、unit track width. A.3 Erase heads reproducing head gaps of the same width dimension or wider than the recorded track must be used to prevent edge effects or fringing. When the recording head gap is narrower than the width of the coating or stripe, as is normal for all motion-picture test films, ther

13、e is a measurement complication involving both the uncertainties in seeing the track and in determining the recording fringing. A4 Basic standards If the recording head is available, the track width is best Motion-picture prints conforming to this standard are usually measured indirectly by measurin

14、g the gap width and adding made on film made in accordance with ANSIISMPTE 102, to this dimension twice the thickness of the test record with magnetic striping done in accordance with magnetic coating. This correction will usually be 0.0003 in ANSIISMPTE 177, and projected in accordance with to 0.00

15、06 in (8 pm to 15 pm). ANSIISMPTE 194. Erasing head gaps used to erase the record specified in this standard should be substantially wider than the record specified. If the recording head is unavailable, the recorded record may be made visible by the use of a carbonyl iron suspen- sion. Care should

16、be taken to apply the minimum quantity that makes the recording visible, so that the developed image is not wider than the actual recorded area. A.2 Reproduclng head gap width If precision measurements or calibrations are to be made on magnetic audio records made in accordance with this standard, 11

17、5 Longliudlnai picture-audlo dlsplacement As a working procedure, the accuracy of picture-audio dis- placement in a projection print is frequently judged by screening in a review room. It is important that the standard thread-path in this review room projector be set accurately to the value specifie

18、d in this standard plus 1 frame for every 50 ft (15 m) separating the loudspeaker from the observer. Otherwise, nonstandard prints may be produced. Annex B (informative) Bibliography ANSIISMPTE 102-1997, Motion-Picture Film (35-mm) - ANSIISMPTE 194-1997, Motion-Picture Film (35-mm) - Perforated CS-1870 Projector Usage - Release Prints Having Four Perforations per Frame ANSVSMPTE 177-1995, Motion-Picture Film (35-mm) - Four-Track Magnetic Audio Release Prints - Magnetic Striping Page 2 of 2 pages