1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationTime and control codeBS EN 60461:2011National forewordThis British Standard is the UK implementation of EN 60461:2011. It is identi-cal to IEC 60461:2010. It supersedes BS EN 604
2、61:2001 which is withdrawn.The UK participation in its preparation was entrusted to Technical CommitteeEPL/100, Audio, video and multimedia systems and equipment.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to incl
3、ude all the necessary provisions of acontract. Users are responsible for its correct application. BSI 2011ISBN 978 0 580 67049 7ICS 33.160.40; 33.170Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the Standard
4、sPolicy and Strategy Committee on 31 July 2011.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 60461:2011EUROPEAN STANDARD EN 60461 NORME EUROPENNE EUROPISCHE NORM March 2011 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalis
5、ation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60461:2011 E ICS 33.160.40; 33.170 Supersedes EN 6
6、0461:2001English version Time and control code (IEC 60461:2010) Code temporel et de pilotage (CEI 60461:2010) Zeit- und Steuercode (IEC 60461:2010) This European Standard was approved by CENELEC on 2011-01-02. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipul
7、ate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard
8、 exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national
9、electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, S
10、weden, Switzerland and the United Kingdom. BS EN 60461:2011EN 60461:2011 - 2 - Foreword The text of document 100/1515/CDV, future edition 4 of IEC 60461 prepared by Technical Area 6, Professional electronics storage media, data structures and equipment, of IEC TC 100, Audio, video and multimedia sys
11、tems and equipment, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60461 on 2011-01-02. This European Standard supersedes EN 60461:2001. EN 60461:2011 includes the following significant change with regard to EN 60461:2001: The time code for progressive television sy
12、stems with a frame rate greater than 30 frames per second is added. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent rights. The following dates w
13、ere fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2011-10-02 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2014-01-02 Annex ZA has been added by CENE
14、LEC. _ Endorsement notice The text of the International Standard IEC 60461:2010 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following note has to be added for the standard indicated: IEC 61169-8:2007 NOTE Harmonized as EN 61
15、169-8:2007 (not modified). _ BS EN 60461:2011- 3 - EN 60461:2011 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following referenced documents are indispensable for the application of this document. For dated references, onl
16、y the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year I
17、SO/IEC 646 1991 Information technology - ISO 7-bit coded character set for information interchange - - ISO/IEC 2022 1994 Information technology - Character code structure and extension techniques - - ITU-R BT.1700 2005 Characteristics of composite video signals for conventional analogue television s
18、ystems - - SMPTE 170M 2004 Television - Composite Analog Video Signal - NTSC for Studio Applications - - SMPTE 258M 1993 Television - Transfer of Edit Decision Lists - - SMPTE 262M 1995 Television, Audio and Film - Binary Groups of Time and Control Codes - Storage and Transmission of Data - - SMPTE
19、309M 1999 Television - Transmission of Date and Time Zone Information in Binary Groups of Time and Control Code - - BS EN 60461:2011 2 60461 IEC:2010(E) CONTENTS INTRODUCTION.8 1 Scope.9 2 Normative references9 3 Terms, definitions and reserved 9 3.1 Terms and definitions 9 3.2 Reserved.11 4 Time re
20、presentation in 30 frames per second and 60 frames per second systems .11 4.1 Definitions of real time and NTSC time.11 4.1.1 Definition of real time.11 4.1.2 Definition of NTSC time .11 4.2 Time address of a frame11 4.2.1 Definition of time address of a frame11 4.2.2 Non-drop frame Uncompensated mo
21、de .12 4.2.3 Drop frame NTSC time compensated mode.12 4.3 Colour frame identification in NTSC analogue composite television systems.12 5 Time representation in 25 frames per second and 50 frames per second systems .12 5.1 Definition of real time.12 5.2 Time address of a frame12 5.3 Colour frame iden
22、tification in PAL analogue composite television systems .13 5.3.1 Colour frame identification .13 5.3.2 Logical relationship 13 5.3.3 Arithmetic relationship .13 6 Time representation in 24-frame systems13 6.1 Definitions of real time and NTSC time.13 6.1.1 Definition of real time.13 6.1.2 Definitio
23、n of NTSC time .14 6.2 Time address of a frame14 7 Structure of the time address and control bits14 7.1 Numeric code 14 7.2 Time address 14 7.3 Flag bits 14 7.3.1 Definition of flag bits 14 7.3.2 Drop frame flag (NTSC composite television system only) 14 7.3.3 Colour frame flag (NTSC and PAL composi
24、te television systems only)14 7.3.4 Binary group flags15 7.3.5 Modulation method specific flag .15 7.4 Use of the binary groups15 7.4.1 Binary group flag assignments .15 7.4.2 Character set not specified and unspecified clock time (BGF2=0, BGF1=0, BGF0=0) .15 7.4.3 Eight-bit character set and unspec
25、ified clock time (BGF2=0, BGF1=0, BGF0=1)15 7.4.4 Date/time zone and unspecified clock time (BGF2=1, BGF1=0, BGF0=0)16 7.4.5 Page/line multiplex system and unspecified clock time (BGF2=1, BGF1=0, BGF0=1) .16 BS EN 60461:201160461 IEC:2010(E) 3 7.4.6 Clock time specified and unspecified character set
26、 (BGF2=0, BGF1=1, BGF0=0)16 7.4.7 Unassigned binary group usage and unassigned clock time (BGF2=0, BGF1=1, BGF0=1) .16 7.4.8 Date/time zone and clock time (BGF2=1, BGF1=1, BGF0=0) 16 7.4.9 Specified clock time and page/line multiplex system (BGF2=1, BGF1=1, BGF0=1) .16 7.5 Clock time reference Binar
27、y group flag combinations.16 8 Linear time code application17 8.1 Code word format 17 8.2 Code word data content .17 8.2.1 LTC code word content 17 8.2.2 Time address.17 8.2.3 Flag bits 17 8.2.4 Binary groups 18 8.2.5 Synchronization word.18 8.2.6 Biphase mark polarity correction 19 8.3 Modulation m
28、ethod 19 8.4 Bit rate 20 8.5 Timing of the code word relative to a television signal 20 8.6 Linear time code interface electrical and mechanical characteristics.21 8.6.1 Measurements.21 8.6.2 Rise/fall time21 8.6.3 Amplitude distortion .21 8.6.4 Timing of the transitions.21 8.6.5 Interface connector
29、21 8.6.6 Output impedance21 8.6.7 Output amplitude .21 9 Vertical interval application Analogue television systems 26 9.1 Code word format 26 9.2 Code word data content .26 9.2.1 VITC code word content.26 9.2.2 Time address.29 9.2.3 Flag bits 29 9.2.4 Binary groups 29 9.2.5 Field mark flag.30 9.2.6
30、Synchronization bits.30 9.2.7 Cyclic redundance check code .30 9.3 Modulation method 31 9.4 Bit timing .31 9.5 Timing of the code word relative to the television signal .32 9.5.1 525/59,94 television system .32 9.5.2 625/50 television system 32 9.6 Location of the address code signal in the vertical
31、 interval .32 9.6.1 Location of the VITC code32 9.6.2 525/59,94 television system .32 9.6.3 625/50 television system 32 9.6.4 Component television system.32 9.7 Redundancy 32 BS EN 60461:2011 4 60461 IEC:2010(E) 9.8 Vertical interval time code waveform characteristics.33 9.8.1 Waveform characteristi
32、cs.33 9.8.2 Logic level .33 9.8.3 Rise/fall time33 9.8.4 Amplitude distortion .33 10 Relationship between LTC and VITC.33 10.1 Time address data.33 10.2 Binary group data 33 10.2.1 General .33 10.2.2 Transferring vertical interval binary group data to linear binary group data.34 10.2.3 Transferring
33、linear binary group data to vertical interval binary group data.34 10.3 VITC and LTC code word comparison 34 11 Progressive systems with frame rates greater than 30 frames per second .36 11.1 Time address of a frame pair in 50 and 60 frames per second progressive systems.36 11.2 Implementation guide
34、lines .36 Annex A (informative) Explanatory notes 37 Annex B (informative) Converting time codes when converting video from 24 fps television systems.39 Bibliography42 Figure 1 Linear time code source output waveform .20 Figure 2 29,97/30 frame linear time code example22 Figure 3 25 frame linear tim
35、e code example .23 Figure 4 24 frame linear time code example .24 Figure 5 Linear time code relationship to 59,94 frame progressive video example .25 Figure 6 525/59,94 vertical interval time code address bit assignment and timing27 Figure 7 625/50 vertical interval time code address bit assignment
36、and timing 28 Figure 8 Vertical interval time code waveform.31 Figure 9 Example of frame labeling for 50 and 60 frames per second progressive systems 36 Figure B.1 Example of conversion of 23,98 fps video to 525/59,94/I40 Figure B.2 Example of conversion of 24 fps high definition video to 625/50/I .
37、41 Table 1 Binary group flag assignments .15 Table 2 LTC time address bit positions .17 Table 3 LTC flag bit positions .18 Table 4 LTC binary group bit positions18 Table 5 LTC synchronization word bit positions and values .19 Table 6 VITC time address bit positions29 Table 7 VITC flag bit positions2
38、9 Table 8 VITC binary group bit positions 30 Table 9 CRC bit positions.31 Table 10 VITC logic level ranges 33 BS EN 60461:201160461 IEC:2010(E) 5 Table 11 Summation of VITC and LTC codeword bit definitions 35 BS EN 60461:2011 8 60461 IEC:2010(E) INTRODUCTION IEC 60461 was originally developed for an
39、alogue television recording systems and thus dealt only with interlaced television systems operating with frame rates up to 30 frames per second. It is, however, flexible enough in design to be used in digital television systems, both standard definition and high definition. The support for progress
40、ive video systems with frame rates above 30 frames per second is described in this International Standard. Clauses 4, 5, and 6 specify the manner in which time is represented in frame-based systems. Clause 7 specifies the structure of the time address and control bits of the code, and sets guideline
41、s for storage of user data in the code. Clause 8 specifies the modulation method and interface characteristics of a linear time code (LTC) source. Clause 9 specifies the modulation method for inserting the code into the vertical interval of a television signal. Clause 10 summarises the relationship
42、between the two forms of time and control code. Clause 11 summarises time code implementations for video formats with frame rates greater than 30 fps. BS EN 60461:201160461 IEC:2010(E) 9 TIME AND CONTROL CODE 1 Scope This International Standard specifies a digital time and control code for use in te
43、levision, film, and accompanying audio systems operating at nominal rate of 60, 59,94, 50, 30, 29,97, 25, 24 and 23,98 frames per second. This International Standard specifies a time address, binary groups, and flag bit structure. In addition, the standard specifies a binary group flag assignment, a
44、 linear time code transport, and a vertical interval time code transport. This International Standard defines primary data transport structures for linear time code (LTC) and vertical interval time code (VITC). This standard specifies the LTC modulation and timing for all video formats. This standar
45、d also defines the VITC modulation and location for 525/59,94 and 625/50 analogue composite and component systems only. NOTE The digital representation of analogue VITC (D-VITC) is specified in SMPTE 266M and is defined for 525/59,94 and 625/50 digital component systems only. High definition formats
46、, such as those documented in SMPTE 274M and SMPTE 296M, should use ancillary time code (ATC) as specified in SMPTE 12M-2 (formerly SMPTE RP 188) for transport of time code in the digital video data stream. For future implementations of time code for digital standard definition formats, the use of A
47、TC rather than D-VITC is encouraged. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments
48、) applies. ISO/IEC 646:1991, Information processing ISO 7-bit coded character set for information interchange ISO/IEC 2022:1994, Information technology Character code structure and extension techniques ITU-R BT.1700-1(2005), Annex 2, Characteristics of composite video signals for conventional analog
49、ue television systems SMPTE 170M:2004, Television Composite Analog Video Signal NTSC for Studio Applications SMPTE 258M:1993, Television Transfer of Edit Decision Lists SMPTE 262M:1995, Television, Audio and Film Binary Groups of Time and Control Codes Storage and Transmission of Data SMPTE 309M:1999, Television Transmission of Date and Time Zone Information in Binary Groups of Time and Control Code 3 Terms, definitions and reserved 3.1 Terms
