1、 Approved February 26, 2016 Copyright 2016 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue., White Plains, NY 10601 (914) 761-1100 SMPTE ST 12-3:2016 SMPTE STANDARD Time Code for High Frame Rate Signals and Formatting in the Ancillary Data Space Page 1 of 15 pages Table of
2、Contents Page Foreword . 3 Intellectual Property 3 Introduction . 3 1 Scope . 4 2 Conformance Notation . 4 3 Normative References . 4 4 Terms and Definitions 5 4.1 Ancillary Time Code (ATC) 5 4.2 Ancillary Time Code for High Frame Rate Time Code (ATC_HFRTC) . 5 4.3 Binary Coded Decimal system (BCD)
3、5 4.4 Codeword . 5 4.5 Drop Frame (DF) 5 4.6 Frame . 5 4.7 Mod . 5 4.8 Time Address . 5 5 Overview (Informative) 5 6 Representation of Time Address in Time Code . 6 6.1 Super-Frame 6 6.2 Frame Identifier Bits . 7 6.3 Frame Number . 8 6.4 Time Address with Frame Counting of 120 (30x4) and 120 with Dr
4、op-Frame Compensation . 8 6.5 Time Address with Frame Counting of 100 . 9 6.6 Time Address with Frame Counting of 72, 96 and 120 (24x5) 9 7 Structure of the Time Code 9 7.1 Numeric Code 9 7.2 Time Address . 9 7.3 Drop Frame Flag 10 7.4 Use of the Binary Group 10 7.5 Codeword Format 10 7.6 Codeword D
5、ata Content 10 SMPTE ST 12-3:2016 Page 2 of 15 pages 8 Format of Ancillary Time Code Packets . 11 9 Format of User Data Words in Ancillary Time Code Packets 11 9.1 General . 11 9.2 Distributed Binary Bits (DBB) 11 9.3 Mapping of the Time Code Data into Ancillary Data Packets . 12 10 Transmission of
6、Ancillary Time Code Packets . 14 10.1 Transmission of Multiple ATC Packets 14 10.2 ATC Packet Transmission Rate . 14 11 Ancillary Time Code Packet Location . 14 11.1 Permissible Insertion Locations . 14 11.2 Preferred Locations for Placement of ATC 14 Annex A Bibliography (Informative) 15 SMPTE ST 1
7、2-3:2016 Page 3 of 15 pages Foreword SMPTE (the Society of Motion Picture and Television Engineers) is an internationally-recognized standards developing organization. Headquartered and incorporated in the United States of America, SMPTE has members in over 80 countries on six continents. SMPTEs Eng
8、ineering 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 interest in their work. SMPTE cooperates closely with other standards-developing organizations,
9、including ISO, IEC and ITU. SMPTE Engineering Documents are drafted in accordance with the rules given in its Standards Operations Manual. SMPTE ST 12-3 was prepared by Technology Committee 32NF. Intellectual Property At the time of publication no notice had been received by SMPTE claiming patent ri
10、ghts 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. SMPTE shall not be held responsible for identifying any or all such patent rights. Introduction This secti
11、on is entirely informative and does not form an integral part of this Engineering Document. This standard forms a portion of one of the oldest SMPTE Standards for Television. SMPTE Time Code was developed originally for analog television recording systems and thus dealt only with interlaced televisi
12、on 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, either standard definition, high definition, and ultra-high definition. The other parts of this suite of documents (SMPTE ST 12-1 and SMPTE ST 12-2) d
13、o not support time code operating at system rates higher than 60 frames per second, even though high frame rate (HFR) devices are already coming into use. This standard is intended to support such devices. This standard defines the time code for HFR and its data structure in the ancillary data space
14、 in a way that is extensible to cover frame rates of up to 960 frames per second. To facilitate a simple approach that is consistent with existing implementations, the time address and ancillary data space formats are inherited from the existing time code standards (SMPTE ST 12-1, SMPTE ST 12-2). SM
15、PTE ST 12-3:2016 Page 4 of 15 pages 1 Scope This standard specifies time code formats with the frame counts 72, 96, 100 and 120 and the frame count 120 with drop-frame compensation. This standard also specifies a transmission format for conveyance of the time code and frame count in the ancillary da
16、ta space of serial digital interfaces. 2 Conformance Notation Normative text is text that describes elements of the design that are indispensable or contains the conformance language keywords: “shall“, “should“, or “may“. Informative text is text that is potentially helpful to the user, but not indi
17、spensable, 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 default, normative, except: the Introduction, any section explicitly labeled as “Informative“ or individual pa
18、ragraphs 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. The keywords, “should“ and “should not“ indicate that, among several possibilities, one is recommended as
19、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 or course of action is deprecated but not prohibited. The keywords “may“ and “need not“ indicate courses o
20、f 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 keyword “forbidden” indicates “reserved” and in addition indicates that the provision will never be defined
21、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 described. A conformant implementation need not implement optional provisions (“may“) and need not implement the
22、m as described. Unless otherwise specified, the order of precedence of the types of normative information in this document shall be as follows: Normative prose shall be the authoritative definition; Tables shall be next; then formal languages; then figures; and then any other language forms. 3 Norma
23、tive References The following standards contain provisions which, through reference in this text, constitute provisions of this engineering document. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this engineer
24、ing document are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. SMPTE ST 12-2:2014, Transmission of Time Code in the Ancillary Data Space SMPTE ST 291-1:2011, Ancillary Data Packet and Space Formatting SMPTE ST 12-3:2016 Page 5 of 15 p
25、ages 4 Terms and Definitions For the purposes of this document, the following terms and definitions apply. 4.1 Ancillary Time Code ATC Ancillary data packets carried in the Ancillary space (VANC or HANC) of a digital television data stream, as defined in SMPTE ST 12-2 and this standard, and payloads
26、 of these packets convey LTC or VITC as well as the “time code” defined in this standard. 4.2 Ancillary Time Code for High Frame Rate Time Code ATC_HFRTC ATC that carries high frame rate time code codewords as defined in this standard. 4.3 Binary Coded Decimal System BCD A means for encoding decimal
27、 numbers as groups of binary bits. Each decimal digit (0-9) is represented by a unique four-bit code. The four bits are weighted with the digits decimal weight multiplied by successive powers of two. Note: For example, the bit weights for a “units” digit would be 1 x 20, 1 x 21, 1 x 22, and 1 x 23,
28、while the bit weights for a “tens” digit would be 10 x 20, 10 x 21, 10 x 22, and 10 x 23. 4.4 Codeword Time address, the flag bit (i.e. drop frame flag) and a binary group for user-defined data codes comprise the codeword, commonly abbreviated as simply “time code” (note that some users spell this “
29、timecode”). 4.5 Drop Frame DF Fractional system rate compensated mode as defined in Section 6.4.3. 4.6 Frame A frame is a complete image unit of a video sequence. 4.7 Mod An abbreviated name of the modulo operator. The expression “n k mod m” would be equivalent to: n is the remainder from the divisi
30、on of k by m. 4.8 Time address An address consisting of hours, minutes, seconds, super-frames, and frame identifier bits. It is intended as a label to identify discrete frames. 5 Overview (Informative) This standard defines time code formats with the frame counts 72, 96, 100 and 120 and the frame co
31、unt 120 with drop-frame compensation and also defines the formatting structure of the ancillary data space for the HFR time code. Implementation of a variable frame count is out of scope of this standard. These frame counts are needed to support the type of HFR equipment already in use. The ancillar
32、y data packet defined in this standard can be conveyed in serial digital interfaces or other applications, e.g., MXF (SMPTE ST 436-1). Reserved bits are assigned for possible future extended frame counts, i.e. counts greater than 120 frames up to 960 frames. SMPTE ST 12-3:2016 Page 6 of 15 pages Fig
33、ure 1 Overview e.g. 120 (24x5) frames This figure illustrates the time code defined in SMPTE ST 12-1 and in this standard, together with an outline of the structure of the ATC packet defined in SMPTE ST 12-2. SMPTE ST 12-3 inherits the time address structure from SMPTE ST 12-1 and defines the frame
34、identifier bits (sub-frame_1, sub-frame_2, sub-frame_3, sub-frame_4 and sub-frame_5, see Section 6.2) to extend the frame counts. Use is made of a super-frame (defined Section 6.1) that comprises an integer multiple of frames at conventional (non-HFR) frame counts of 24, 25, 30 frames or 30 frames w
35、ith drop-frame compensation. In SMPTE ST 12-3 the binary group flags are replaced with the frame identifier bits. These flags provide eight unique combinations which signify the use of the binary groups in SMPTE ST 12-1, whereas the use of binary group flags in this standard is deprecated. SMPTE ST
36、12-3 defines three differences so as to be able to embed the HFR time code onto the ATC defined in SMPTE ST 12-2. Firstly, SDID code is defined as 61h to indicate a HFR ancillary time code packet. Secondly, DBB1 is defined as 8xh where x identifies a HFR time code from up to 16 ATCs. Thirdly, DBB2 i
37、dentifies the particular super-frame count associated with each HFR frame count as well as the value of N, the multiple of the super-frame count that gives the HFR frame count. Section 9.2.2 describes the details. 6 Representation of Time Address in Time Code 6.1 Super-Frame A super-frame shall be a
38、 group of N frames such that the super-frame count is compatible with SMPTE ST 12-1 as defined in Table 1. SMPTE ST 12-3:2016 Page 7 of 15 pages Table 1 Super-frame counts N HFR Frame Count Super-frame Count Count Mode 4 120 30 Non-drop frame 4 120 30 Drop frame 4 100 25 Non-drop frame 5 120 24 Non-
39、drop frame 4 96 24 Non-drop frame 3 72 24 Non-drop frame Application formats can define the representation of N. Section 9.2.2 DBB2 defines the representation of N in DBB2. 6.2 Frame Identifier Bits The frame identifier bits shall be sub-frame_1, sub-frame_2 , sub-frame_3, sub-frame_4 and sub-frame_
40、5 as defined in Table 2. The frame identifier bits comprise the frame identifier number which identifies a count for a frame within a super-frame. Table 2 shows the positions of the frame identifier bits within the codeword (see also Table 3 and Table 4). For comparison, it also shows how the corres
41、ponding bits are used in SMPTE ST 12-1. Table 2 Frame identifier bit positions 120, 120DF frames (30, 30DF x 4) 100 frames 120 frames (24 x 5) 96, 72 frames ST 12-1 definition (informative) 11: Sub-frame_2 11: Sub-frame_2 11: Sub-frame_2 11: Sub-frame_2 Color frame flag 27: Sub-frame_1 59: Sub-frame
42、_1 27: Sub-frame_1 27: Sub-frame_1 Field identification flag 43: Sub-frame_3* 27: Sub-frame_3* 43: Sub-frame_3 43: Sub-frame_3* Binary group flag BGF0 58: Sub-frame_4* 58: Sub-frame_4* 58: Sub-frame_4* 58: Sub-frame_4* Binary group flag BGF1 59: Sub-frame_5* 43: Sub-frame_5* 59: Sub-frame_5* 59: Sub
43、-frame_5* Binary group flag BGF2 Bits b43, b58 and b59 shall be zero in codewords for 120(30x4), 120DF(30DFx4), 96 and 72 frames. Bits b27, b43 and b58 shall be zero in codewords for 100 frames. Bits b58 and b59 shall be zero in codewords for 120(24x5) frames. The combination of super-frame and the
44、frame identifier bits identifies the frame number (see Section 6.3). Note 1: *Sub-frame_3 (except 24x5), sub-frame_4 or sub-frame_5 are not used in this version of this standard, but are intended to enable future extension to higher frame counting beyond 120 frames and are zero. Note 2: Sub-frame_1
45、is the MSB of the count of the frame identifier number, in a position consistent with the “field identification flag“ of SMPTE ST 12-1. Sub-frame_n is intended to follow a cycle whose frame rate is 2n times the super-frame rate. This structure allows a subset of the frame identifier bits to be used
46、for a proxy time code of the original. For example, 60-frame count time code can be used as a proxy of 120 to 960 frame count time code in an off-line edit environment. Thus an edit list based on 60 frame time code is applied to any television systems operating at a system rate that is multiple of 6
47、0, i.e. 120, 180, 240 up to 960 frames per second. SMPTE ST 12-3:2016 Page 8 of 15 pages 6.3 Frame Number The frame number shall be calculated as follows. The frame number shall be incremented every frame. For the case of N = 3, 4, that is, 120, 120DF (as a multiple of 30, 30DF), 100, 96 and 72 fram
48、e time codes frame number = 10 x (Tens of super-frames) + (Units of super-frames) x N + (sub-frame_1 bit x 1/21 + sub-frame_2 bit x 1/22) x 22 For the case of N = 5, that is, 120 frame time code (as a multiple of 24) frame number = 10 x (Tens of super-frames) + (Units of super-frames) x N + (sub-fra
49、me_1 bit x 1/21 + sub-frame_2 bit x 1/22 + sub-frame_3 bit x 1/23) x 23 In 120, 120DF (as a multiple of 30, 30DF), 100, 96 and 72 frame time codes, the frame identifier bits consist of two bits: the sub-frame_1 bit and the sub-frame_2 bit. In 120 frame time code (as a multiple of 24), the frame identifier bits consists of three bits: the sub-frame_1 bit, the sub-frame_2 bit and the sub-frame_3 bit. frame identifier number frame number mod N, where N = (Time Code Frame Count) / (Super-frame C
