1、 IEC/TS 62644 Edition 1.0 2012-10 TECHNICAL SPECIFICATION Professional video storage equipment Guideline of time code transmission IEC/TS 62644:2012(E) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2012 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this pub
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8、er Service Centre - webstore.iec.ch/csc If you wish to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csciec.ch. IEC/TS 62644 Edition 1.0 2012-10 TECHNICAL SPECIFICATION Professional video storage equipment Guideline of time code tra
9、nsmission INTERNATIONAL ELECTROTECHNICAL COMMISSION K ICS 33.160.40 PRICE CODE ISBN 978-2-83220-414-6 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. 2 TS 62644 IEC:2012(E) CONTENTS FOREWORD .
10、 3 INTRODUCTION . 5 1 Scope . 6 2 Normative references . 6 3 Terms and definitions . 6 4 Transmission of time code 7 4.1 Time address of a frame pair in progressive systems 7 4.2 Relationship between frame pair and ATC . 7 4.3 Relationship between the reference signal and ATC 8 Bibliography 10 Figur
11、e 1 Time address of frame pair 7 Figure 2 Relationship between reference signal and ATC 8 Figure 3 Example of relationship between reference signal and ATC (1/2 speed play) . 9 TS 62644 IEC:2012(E) 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ PROFESSIONAL VIDEO STORAGE EQUIPMENT GUIDELINE OF TIME C
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25、 technical area 6: Storage media, data structures, equipment and systems, of IEC technical committee 100: Audio, video and multimedia systems and equipment. 4 TS 62644 IEC:2012(E) The text of this technical specification is based on the following documents: Enquiry draft Report on voting 100/1968/DT
26、S 100/2022/RVC Full information on the voting for the approval of this technical specification can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. The committee has decided that the contents of this p
27、ublication will remain unchanged until the stability date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be transformed into an International Standard, reconfirmed, withdrawn, replaced by a revised editi
28、on, or amended. A bilingual version of this publication may be issued at a later date. TS 62644 IEC:2012(E) 5 INTRODUCTION Time and control code is standardized in IEC 60461 and SMPTE ST 12-1:2008. Transmission of time code is standardized in SMPTE ST 12-2:2008. Reference signal is often used for pr
29、ofessional video storage in order to synchronize all equipment in a system. However there are no clear specifications for the transmission of time code under such system operation in these standards. When the system treats progressive video whose frame rate is 50 Hz or 59,94 Hz and when it uses refe
30、rence signal, time code transmission of equipment may be treated differently and the interoperability may not be maintained. Therefore, clear guidelines of time code transmission for professional video storage in such a system operation are expected. 6 TS 62644 IEC:2012(E) PROFESSIONAL VIDEO STORAGE
31、 EQUIPMENT GUIDELINE OF TIME CODE TRANSMISSION 1 Scope This Technical Specification specifies the relationship between the reference signal and Ancillary Time Code (ATC) for use in professional storage equipment operating at 50 frames- per-second or 59,94 frames-per-second and handling progressive v
32、ideo signal under the system operation to maintain the frame pair which is composed of two frames. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited
33、applies. For undated references, the latest edition of the referenced document (including any amendments) applies. SMPTE ST 12-1:2008, Television Time and Control Code SMPTE ST 12-2:2008, Television Transmission of Time Code in the Ancillary Data Space SMPTE ST 318:1999, Television and Audio Synchro
34、nization of 59.94 or 50-Hz Related Video and Audio Systems in Analog and Digital Areas Reference Signals SMPTE ST 274:2008, Television 1 920 1 080 Image Sample Structure, Digital Representation and Digital Timing Reference Sequences for Multiple Picture Rates 3 Terms and definitions For the purposes
35、 of this document, the following terms and definitions apply. 3.1 time code abbreviation of time and control code defined in SMPTE ST 12-1:2008 3.2 frame pair two time-consecutive frames of a video signal for which there is a first frame and a second frame 3.3 ATC_VITC1 Ancillary Time Code Vertical
36、Interval Code #1 Payload Type defined in SMPTE ST 12-2:2008 3.4 ATC_VITC2 Ancillary Time Code Vertical Interval Code #2 Payload Type defined in SMPTE ST 12-2:2008 3.5 field mark flag field identification flag defined in SMPTE ST 12-1:2008 TS 62644 IEC:2012(E) 7 3.6 reference signal external referenc
37、e signal for synchronization defined in SMPTE ST 318:1999 or SMPTE ST 274:2008 4 Transmission of time code 4.1 Time address of a frame pair in progressive systems This subclause is given for information. Time address of a frame pair in progressive systems is specified in SMPTE ST 12-1:2008 as follow
38、s. Since the frame frequency of 50 frames-per-second and 59,94 frames-per-second progressive system exceeds the frame count capacity of the time address, the count is constrained to increment only every other frame (as shown in Figure 1). This results in an edit resolution of two frames. Where the t
39、ime code is conveyed as VITC data (for example as in ATC), it is recommended that the field mark flag is used to identify each frame of the frame pair. The preferred implementation is to set the field mark flag of the VITC data to zero for the first frame of a pair and to one for the second frame of
40、 a pair. Figure 1 Time address of frame pair 4.2 Relationship between frame pair and ATC This subclause is given for information only. The relationship between frame pair and ATC is specified in SMPTE ST 12-2:2008 as follows. For progressive systems running at 50 frames-per-second or 59,94 frames-pe
41、r-second, it is recommended that a packet of the ATC_VITC1 payload type with the field mark flag set to zero and associated with the first frame of a pair alternate with a packet of the ATC_VITC2 payload type with the field mark flag set to one and associated with the second frame of a pair. IEC 189
42、2/12 8 TS 62644 IEC:2012(E) VITC data in ATC_VITC1 and ATC_VITC2 payload types use the field mark flag to identify each of the frames of a frame pair as follows: A logical zero represents the first frame and a logical one represents the second frame of the pair of progressive frames. 4.3 Relationshi
43、p between the reference signal and ATC This guideline is for use in professional storage equipment operating at 50 frames-per-second or 59,94 frames-per-second and handling a progressive video signal under the operation using the reference signal to maintain a frame pair by limiting the edit resolut
44、ion of two frames. A packet of the ATC_VITC1 payload type in the output of storage equipment associated with the first frame of a pair should associate with field1 of the reference signal. A packet of the ATC_VITC2 payload type in the output of storage equipment associated with the second frame of a
45、 pair should associate with field2 of the reference signal. Figure 2 shows the relationship between the reference signal and ATC. A field mark flag associated with the time code of recorded video content should be played back synchronized with the play back video content. When the storage equipment
46、is playing back at the same speed as the recorded speed, the relationship of reference signal, ATC_VITC1, ATC_VITC2 and field mark flag should be as follows. reference signal field1: ATC_VITC1 payload type, field mark flag set to 0 reference signal field2: ATC_VITC2 payload type, field mark flag set
47、 to 1 Figure 2 Relationship between reference signal and ATC The transmission of ATC Packets playing back at a different speed from the recorded speed is not the same as the transmission in normal play speed. A field mark flag associated with the time code of recorded video content may synchronize w
48、ith the frame pair of the video content and may not synchronize with field 1 and 2 of the reference signal. Figure 3 shows an example of a relationship between reference signal and ATC at 1/2 speed play. IEC 1893/12 TS 62644 IEC:2012(E) 9 Figure 3 Example of relationship between reference signal and
49、 ATC (1/2 speed play) Playing back at different speed from the recorded speed reference signal field1: ATC_VITC1 payload type, field mark flag set to 0 or 1 reference signal field2: ATC_VITC2 payload type, field mark flag set to 0 or 1 EXAMPLE still mode of the video with field flag = 0 Time code of ATC remains the same value as associated video reference signal field1: ATC_VITC1 payload type, field mark flag set to 0 reference signal field2: ATC_VITC2 payload type, field m
