SMPTE ST 12-2-2014 Transmission of Time Code in the Ancillary Data Space.pdf

1、 Copyright 2014 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue, White Plains, NY 10601 (914) 761-1100 Approved February 20, 2014 Table of Contents Page Foreword . 3 Intellectual Property 3 Introduction 4 1 Scope . 5 2 Conformance Notation . 5 3 Normative References . 5 4 D

2、efinitions and Acronyms 6 4.1 Ancillary Time Code (ATC) . 6 4.2 Frame 6 4.3 Field 6 4.4 LSB . 6 4.5 MSB 6 4.6 UDW 6 5 Format of Ancillary Time Code Packets . 6 5.1 Ancillary Time Code Packet Layout 7 5.2 User Data Words in Ancillary Time Code . 7 6 Format of User Data Words in Ancillary Time Code Pa

3、cket 8 6.1 Bit Assignments within the UDW 8 6.1.1 UDW Bits b9 and b8 . 8 6.1.2 UDW Bits b7 through b4 . 8 6.1.3 UDW Bit b3 . 8 6.1.4 UDW Bits b2 through b0 . 8 6.2 Distributed Binary Bits (DBB) 8 6.2.1 DBB1 Payload Type . 8 6.2.2 DBB2 . 9 6.3 Mapping of the Time code Data into Ancillary Data Packets

4、 12 7 Transmission of Ancillary Time Code Packets. 14 7.1 Multiple Transmission of ATC Packets . 14 7.2 ATC Packet Transmission Rate 14 8 Ancillary Time Code Packet Location . 14 8.1 Permissible Insertion Locations . 14 8.2 Preferred Locations for Placement of ATC 14 8.2.1 High Definition Television

5、 (HDTV) Systems 15 8.2.2 Standard Definition Television (SDTV) Systems . 15 Page 1 of 18 pages SMPTE ST 12-2:2014 Revision of SMPTE 12M-2:2008 SMPTE STANDARD Transmission of Time Code in the Ancillary Data Space SMPTE ST 12-2:2014 Page 2 of 18 pages 9 Correspondence Between LTC/VITC and ATC . 15 9.1

6、 Flag Field for Interlaced Television Systems 15 9.2 Progressive Television Systems with Frame Rates Greter than 30 Frames Per Second . 16 9.3 Implementation Guidelines (Informative) . 16 Annex A Bibliography (Informative) 17 Annex B Time Code System “Roadmap“ (Informative) 18 Index of Tables Page T

7、able 1 User Data Word (UDW) format 7 Table 2 DBB1 (payload type) Distributed binary bit group coding . 9 Table 3 DBB2 (payload type) Distributed binary bit group coding . 10 Table 4 VITC Line select number (SDTV interfaces only) 11 Table 5 Coding of validity and process bits 11 Table 6 Mapping of ti

8、me Code Data into UDW 12 Table 7 Preferred locations for Insertion in HDTV signals . 15 SMPTE ST 12-2:2014 Page 3 of 18 pages Foreword SMPTE (the Society of Motion Picture and Television Engineers) is an internationally-recognized standards developing organization. Headquartered and incorporated in

9、the United States of America, SMPTE has members in over 80 countries on six continents. SMPTEs Engineering Documents, including Standards, Recommended Practices and Engineering Guidelines, are prepared by SMPTEs Technology Committees. Participation in these Committees is open to all with a bona fide

10、 interest in their work. SMPTE cooperates closely with other standards-developing organizations, including ISO, IEC and ITU. SMPTE Engineering Documents are drafted in accordance with the rules given in its Standards Operations Manual. SMPTE Standard ST 12-2 was prepared by Technology Committee 33TS

11、. Intellectual Property At the time of publication no notice had been received by SMPTE claiming patent rights essential to the implementation of this Engineering Document. However, attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.

12、SMPTE shall not be held responsible for identifying any or all such patent rights. SMPTE ST 12-2:2014 Page 4 of 18 pages Introduction This section is entirely informative and does not form an integral part of this document. This standard forms a portion of one of the oldest SMPTE Standards for Telev

13、ision. SMPTE Time Code was developed originally for analog 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 defi

14、nition and high definition. The actual transport of the codewords for digital systems varies significantly from the transport methods defined for analog systems, and is defined in this document (formerly named SMPTE RP 188). The time and control code information is carried as the payload of ancillar

15、y packets which are located in the Ancillary data space of a digital television signal. This type of a time and control code transport is applicable to 8-, 10-, or 12-bit television systems. For television storage systems the time address that forms part of the time code is primarily intended as a l

16、abel to identify discrete frames. SMPTE ST 12-2:2014 Page 5 of 18 pages 1 Scope This standard defines a transmission format for conveyance of linear (LTC) or vertical interval (VITC) time code data formatted according to SMPTE ST 12-1 in 8-, 10-, or 12-bit digital television data interfaces. Time co

17、de information is transmitted in the ancillary data space as defined in SMPTE ST 291-1. Multiple time codes can be transmitted within a single digital video data stream. Other information (such as real time clock, film transfer, DTTR tape timer, and user-defined information) may also be carried in t

18、he ancillary time code packet. This standard is applicable to digital television data interfaces, whether high definition or standard definition. 2 Conformance Notation Normative text is text that describes elements of the design that are indispensable or contains the conformance language keywords:

19、“shall“, “should“, or “may“. Informative text is text that is potentially helpful to the user, but not indispensable, and can be removed, changed, or added editorially without affecting interoperability. Informative text does not contain any conformance keywords. All text in this document is, by def

20、ault, normative, except: the Introduction, any section explicitly labeled as “Informative“ or individual paragraphs that start with “Note:” The keywords “shall“ and “shall not“ indicate requirements strictly to be followed in order to conform to the document and from which no deviation is permitted.

21、 The keywords, “should“ and “should not“ indicate that, among several possibilities, one is recommended as particularly suitable, without mentioning or excluding others; or that a certain course of action is preferred but not necessarily required; or that (in the negative form) a certain possibility

22、 or course of action is deprecated but not prohibited. The keywords “may“ and “need not“ indicate courses of action permissible within the limits of the document. The keyword “reserved” indicates a provision that is not defined at this time, shall not be used, and may be defined in the future. The k

23、eyword “forbidden” indicates “reserved” and in addition indicates that the provision will never be defined in the future. A conformant implementation according to this document is one that includes all mandatory provisions (“shall“) and, if implemented, all recommended provisions (“should“) as descr

24、ibed. A conformant implementation need not implement optional provisions (“may“) and need not implement them as described. 3 Normative References The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the

25、editions indicated were valid. 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 of the standards indicated below. SMPTE ST 12-1:2014, Time and Control Code SMPTE ST 291-1:2011, An

26、cillary Data Packet and Space Formatting SMPTE RP 168:2009, Definition of Vertical Interval Switching Point for Synchronous Video Switching SMPTE ST 12-2:2014 Page 6 of 18 pages 4 Definitions and Acronyms 4.1 Ancillary Time Code (ATC) The acronym ATC refers to the bitstream carried in either the Ver

27、tical Ancillary space (VANC) or the Horizontal Ancillary space (HANC) of a digital television data stream, as described in this document, and is used to convey time code data formatted as LTC, VITC, or both. Note: ATC may also be used to carry other information as defined in other documents. ATC is

28、a data transport applicable to both High Definition television (HDTV) and Standard Definition television (SDTV) digital video formats. 4.2 Frame A frame contains all of the lines of spatial information of a video signal required to make up one complete picture (including any necessary associated syn

29、chronization lines). For progressive video, these lines contain picture samples, captured at one time instant, starting from the top of the frame and continuing through successive lines to the bottom of the frame. 4.3 Field For interlaced video, a frame consists of two fields. One of these fields wi

30、ll commence one field period later than the other. See SMPTE ST 170 for an example of such a system. Composite television standards require multiple fields in a “color sequence,” but that does not alter this documents nominal terminology. 4.4 LSB Least significant bit. 4.5 MSB Most significant bit.

31、4.6 UDW The acronym UDW is an abbreviation for “user data word“ as defined in SMPTE ST 291. 5 Format of Ancillary Time Code Packets Each data packet shall comply with the format defined in SMPTE ST 291 for a type 2 ANC packet. It consists of the ancillary data flag (ADF), the data ID (DID), the seco

32、ndary data ID (SDID), the data count (DC), the user data words (UDW), and the checksum (CS). The UDW consists of the data payload. The DID and SDID shall be set to: DID 60h SDID 60h The data count word for ancillary time code shall be set to: DC 10h References to User Data Word (UDW) bits in this st

33、andard are for a 10-bit User Data Word. Correspondence between an 8-bit word and a 10-bit word is shown in Table 1. In the case of 12-bit representation, the ancillary data is defined by the seven most significant bits of the 12-bit data and the five least significant bits are defined to be zero. SM

34、PTE ST 12-2:2014 Page 7 of 18 pages Figure 1 Ancillary Time Code packet format 5.1 Ancillary Time Code Packet Layout One ancillary data packet shall fully represent an ancillary time code (ATC) codeword (see Figure 1). 5.2 User Data Words in Ancillary Time Code All User Data Words of the Ancillary T

35、ime Code packets are formatted as shown in Table 1. Table 1 User Data Word (UDW) format UDW bit (12-bit words) UDW bit (10-bit words) UDW8 bit (8-bit words) Assignment b0 (LSB) N/A N/A Set to 0 in 12-bit words, N/A in 10-bit and 8-bit words b1 N/A N/A Set to 0 in 12-bit words, N/A in 10-bit and 8-bi

36、t words b2 b0 (LSB) N/A Set to 0 in 12-bit and 10-bit words, N/A in 8-bit words b3 b1 N/A Set to 0 in 12-bit and 10-bit words, N/A in 8-bit words b4 b2 b0 Set to 0 in 12-bit, 10-bit, and 8-bit words b5 b3 b1 Distributed binary bit (DBB) b6 b4 b2 ANC binary group LSB b7 b5 b3 ANC binary group b8 b6 b

37、4 ANC binary group b9 b7 b5 ANC binary group MSB b10 b8 b6 12-bit - Even parity for data contained in UDW bit 9 through bit 0 10-bit - Even parity for data contained in UDW bit 7 through bit 0 8-bit - Even parity for data contained in UDW bit 5 through bit 0 b11 (MSB) b9 (MSB) b7 12-bit - Not bit 10

38、. 10-bit - Not bit 8. 8-bit - Not bit 6. DIDSDIDDCChecksumU D W p a y l o a d = T i m e C o d e d a t a( 1 6 A N C d a t a g r o u p s )( t a b l e 6 )B i t b 3 = D B B 1 B i t b 3 = D B B 2B i t b 2 = se t t o 0 B i t b 2 = se t t o 0B i t b 0 = b 1 = se t t o 0 B i t b 0 = b 1 = se t t o 0B i t b

39、9 = n o t b i t b 8B i t b 8 = P a r i t y10bitinterfaceU D W 1 t h r u U D W 8 U D W 9 t h r u U D W 1 660h60h10hb9b 8b7b6b5b4b3b2b1b0b7b6b5b4b3b2b1b0b11b10b9b 8b7b6b5b4b3b2b1b01 0 b i t1 2 b i t 8 b i tA T C p a cke tSMPTE ST 12-2:2014 Page 8 of 18 pages 6 Format of User Data Words in Ancillary Ti

40、me Code Packet 6.1 Bit Assignments within the UDW 6.1.1 UDW Bits b9 and b8 Bits b9 shall equal not b8, and b8 shall be the even parity for bits b7 through b0. 6.1.2 UDW Bits b7 through b4 Bits b7 through b4 of UDW-1 through UDW-16 shall form an array of ancillary data groups into which the time code

41、 codewords formatted per SMPTE ST 12-1 shall be mapped. Bit b4 of each UDW represents the LSB of each group (see Table 6). 6.1.3 UDW Bit b3 Two groups of control bits shall be distributed across Bit b3 of UDW-1 through UDW-16 (see Figure 1, Section 6.2, Table 2, and Table 3). 6.1.4 UDW Bits b2 throu

42、gh b0 Bits b2 through b0 shall be set to zero. 6.2 Distributed Binary Bits (DBB) Bit b3 of UDW-1 through UDW-16 shall form two groups of distributed binary bits known as DBB1 and DBB2. Information coded in the DBB1 and DBB2 distributed binary bit groups are defined in Table 2 and Table 3, and is ill

43、ustrated in Figure 1. 6.2.1 DBB1 Payload Type The first group of distributed binary bits (DBB1) shall be formed by bit 3 of UDW-1 through UDW-8, where UDW-1 (b3) represents the LSB and UDW-8 (b3) represents the MSB. The DBB1 bits shall define what type of data is being carried in the time code bits

44、(b7 to b4) of the UDW as defined in Table 2. 6.2.1.1 Ancillary Time Code Linear Code Payload Type The acronym “ATC_LTC” refers to ATC packets that carry linear time code (LTC) codewords as defined in SMPTE ST 12-1 and have the distributed binary bit group 1 (DBB1) value of 00h (see Table 2). 6.2.1.2

45、 Ancillary Time Code Vertical Interval Code #1 Payload Type The acronym “ATC_VITC1” refers to ATC packets that carry vertical interval time code (VITC) codewords as defined in SMPTE ST 12-1 and have the distributed binary bit group 1 (DBB1) value of 01h (see Table 2). The codeword contents shall com

46、ply with the requirements of SMPTE ST 12-1, Section 10.2 (“Codeword data content”), should carry a matching time address to any ATC_LTC packet carried in the same frame of video, and shall further comply with the requirements of Section 9 in this document. 6.2.1.3 Ancillary Time Code Vertical Interv

47、al Code #2 Payload Type The acronym “ATC_VITC2” refers to ATC packets that carry vertical interval time code (VITC) codewords as defined in SMPTE ST 12-1 and have the distributed binary bit group 1 (DBB1) value of 02h (see Table 2). The codeword contents shall comply with the requirements of SMPTE S

48、T 12-1, Section 10.2 (“Codeword data content”) and should carry a matching time address to any ATC_LTC packet carried in the same frame of video. See Section 9 for additional information. SMPTE ST 12-2:2014 Page 9 of 18 pages Table 2 DBB1 (payload type) Distributed binary bit group coding Bit 3 of U

49、DW Distributed binary bit (DBB1) MSB LSB Definition UDW-8 through UDW-1 0 0 0 0 0 0 0 0 Linear time code (ATC_LTC) 0 0 0 0 0 0 0 1 Vertical interval time code #1 (ATC_VITC1) 0 0 0 0 0 0 1 0 Vertical interval time code #2 (ATC_VITC2) 0 0 0 0 0 0 1 1 through 0 0 0 0 0 1 0 1 User defined 0 0 0 0 0 1 1 0 Film data block (transferred from reader1) 0 0 0 0 0 1 1 1 Production data block (transferred from reader1) 0 0 0 0 1 0 0 0 through 0 1 1 1 1 1 0 0 Locally generated time a