1、STD-SMPTE RP L50-ENGL 2000 E 8357403 0004LBO 385 RP 150-2000 SMPTE RECOMMENDED PRACTICE Revision of RP 150-1993 Channel Assignments and Test Leader for Magnetic Film Masters Intended for Transfer to Video Media Having Stereo Audio 1 Scope This practice specifies the left- and right-channel assignmen
2、ts for stereo usage on magnetic film masters intended for transfer to video media. It also gives recommended test signals for use on the head leader of the magnetic master. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions
3、of this practice. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this practice are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. ANSVIEEE 152-1
4、992, Audio Program Level Measurement ANSVSMPTE 86-1 996, Motion-Picture Film - Magnetic Audio Records - Two, Three, Four and Six Records on 35-mm and One Record on 17.5-mm Magnetic Film ANSVSMPTE 208M-1992 (R1998), Motion-Picture Film - 35- and 16-mm Magnetic Audio Records - Recorded Characteristics
5、 SMPTE EG 9-1 995, Audio Recording Reference Level for Post-Production of Motion-Picture Related Materials 3 Track assignment 3.1 Track 1 shall contain the record intended for the left loudspeaker, and track 2 shall contain the record intended for the right loudspeaker, with left and right determine
6、d from the position Page 1 of 2 pages of a viewer watching a screen. When more than two tracks are recorded, all odd-numbered tracks shall contain information for the left loud- speaker, and all even-numbered tracks shall contain information for the right loudspeaker. 3.2 The identity of the track n
7、umbers is con- tained in ANSVSMPTE 86, which specifies the position, dimensions, and reproducing speed for the track format in use. 4 Headleader 4.1 The first test section of the leader shall be a 1 -kHz sine-wave signal recorded at reference level. The tone shall be recorded simultaneously and in p
8、hase on the channels of the master for a duration of 10 s. The reference level is speci- fied in SMPTE EG 9. 4.2 The second section shall identify the channels audibly by sequencing in time one beep on the left channel and two beeps on the right channel. 4.3 The third section shall be a 10-kHz sine-
9、 wave signal recorded at a relative flux level equal to reference level, with the recorded char- acteristic frequency response of ANSVSMPTE 208M applied. The tone shall be recorded simul- taneously and in phase on the channels of the master for a duration of 20 s. 4.4 The fourth section shall be pin
10、k noise recorded simultaneously and in phase on the two channels of the master for a duration of 30 s. It shall be recorded at the reference level as read by a vu meter at 15 dB below the reference level, with the recorded characteristic specified in 4.3 applied. (The objective of using a pink-noise
11、 test signal is to obtain a reference signal with equal energy in equal logarithmic frequency intervals within the audio bandwidth.) Copyright O 2000 by the SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartxiale Ave., White Plains. NY 10607 (914)761-1100 Approved May 30,2000 RP 150-2000
12、 STD=SMPTE RP 150-ENGL 2000 D 8357403 0004383 2LL H 4.4.1 The level in each one-third octave band shall be to the tolerances given in ANSVSMPTE 208M. 4.5 If companding noise-reduction systems are in use, the fifth section of the leader shall be the tone generated by the noise-reduction system for it
13、s reference level for a duration of 10 s. Such tones generally have audible identifying charac- teristics, such as a deliberate periodic frequency shift, to identify the type of noise reduction audibly. 4.4-2 The VU meter shall be as specified in ANSIAEEE 152. Annex A (informative) Additional inform
14、ation A.1 Uses of referencelevel tone A.1.1 Clauses A.1.1.1 and A.1.1.2 provide interactive ad- justments which may have to be performed more than once to optimize the results. A.l.l.1 The reference level tone may be used for setting the preliminary head-mounting adjustments such as coarse ro- tatio
15、n, azimuth, zenith, and height by setting the appropriate mechanical adjustments for the highest and most level-sta- ble output. A.1.1.2 An X-Y display of the reference tone on an oscillo- scope may be used for coarse azimuth setting using the following method: Connect the preamplifier outputs corre
16、sponding to the two channels which represent the outside tracks on the film to the X and Y inputs of an oscilloscope, respectively. With the sensitivity of the preamplifier channels set to play the film at the oscilloscope connection point at equal voltages, and the sensitivity of the X and Y oscill
17、oscope channels made equal, adjust the azimuth for a 45“ diagonal line on the oscilloscope. Setting the azimuth coarsely, first at medium frequencies before adjusting at high frequencies, ensures that when fine adjustments are made for best high-frquency azimuth, they take place on the same cycle of
18、 the high frequency without the possibility of displacement by one full cycle which can lead to a false peak. A.1.2 The reference-level tone may also be used as a rela- tive channel polarity test by using an x-Y display to check that each of the preamplifier outputs corresponding to the records, com
19、pared to a reference channel output, has the same slope, not the opposite slope, which would indicate a polarity reversal in the head or preamplifier wiring. A.2 Uses of pink noise A.2.1 Pink noise can be used to obtain the best overall azimuth by observing a Lissajous pattern on an oscilloscope wit
20、h the X and Y axes connected to the signals from the two channels. When the reproducer sensitivity and equalization have been set for equal performance in the channels, and the azimuth is correct, a line will be displayed at a 45“ angle, not a fuzzy ellipse. Pink noise has an advantage over sine- wa
21、ve tones for azimuth adjustment as it produces unambig- uous results. One cannot misadjust by one full cycle. A.22 In addition, pink noise can be used with a constant- percentage bandwidth spectrum analyzer, such as a one- third-octave band analyzer, to set equalization adjustments. Page 2 of 2 pages
