- 7 - TS62644IEC:2012(E) 3.6 reference signal reference signalfor synchronization defined din SMPTEST318:1999 external or SMPTE ST 274:2008 4 Transmissionoftime code 4.1 Timeaddressofaframepairinprogressivesystems This subclause is given for information. Time address of a frame pair in progressive systems is specified in SMPTE ST 12-1:2008 as (Scientific), Inc., follows. Since the frame frequency of 5o 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. Wherethe time 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 a pair. LTC8ObitCODEWORD Time Address = 01:12:23:21 VITC data in ATC VITC data in ATC Time Address = 01:12:23:21 Time Address = 01:12:23:21 Field Flag Bit =0 Field Flag Bit =1 Video Frame Video Frame Video Frame Frame Label = 01:12:23:21:0 Frame Label = 01:12:23:21:1 Frame Label = 01:12:23:20:1 Frame Pair IEC1892/12 reproduction or distribution is permitted. Figure 1-Time address of frame pair 4.2 RelationshipbetweenframepairandATC Thissubclauseisgivenforinformationonly. The relationship between frame pair andATC is specified in SMPTE ST12-2:2008 as follows. For progressive systems running at 50 frames-per-second or 59,94 frames-per-second, it is recommended that a packet of the ATC_ViTC1payload 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 . Uncontrolled when payload type with the field mark flag set to one and associated with the second frame of a pair. prin material - 8 - TS 62644IEC: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 logicalone represents the second frame of the pair of progressiveframes. 4.3 RelationshipbetweenthereferencesignalandATC 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 resolution 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 pair should associate with field2 of the reference signal. Figure 2 shows the relationship between the reference signal and ATC. entific), A field mark flag associated with the time code of recorded video content should be played nc. back synchronizedwiththeplayback video content. When the storage equipment 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. ec reference signal field1: ATC_VITC1 payload type, field mark flag set to 0 reference signal field2:ATC_VITC2payload type,field mark flag set to 1 50p/59.94p video referencesignal operation reference signal 50i/59.94i reference signal 50i/59,94i field1 field2 field1 field2 frame pair frame pair outputvideo No further ATC_VITC1 ATC_VITC2 ATC_VITC1i ATC_VITC2 50p/59.94p field mark field mark ifield mark field mark flag= 0 I flag= 1 iflag= 0 flag= 1 IEC1893/12 Figure2-Relationshipbetween referencesignal andATC ior 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. tion A field mark flag associated with the time code of recorded video content may synchronize with the frame pair of the video content