5/9/13Alpermann+Velte time code and ancillary data systems, faq, Ancillary Time Code (ATC) according to SMPTE 12M-2 Ancillary Time Code (ATC) according to SMPTE 12M2 Overview The SMPTE standard SMPTE 12M22008 defines the “Transmission of Time Code in the Ancillary Data Space” and replaces the RP 188. In the past there were different methods of implementations regarding ATC. This note describes the implementation of ATC according to SMPTE 12M2 and what are the changes regarding Alpermann+Velte time code modules. The following specifications are concerned with ancillary time code: Standard RP 196 DID 64h 64h F5h 60h DBN/SDID 64h 7Fh 00h 60h DC 8h 9h 8h 10h Time Code Type HANC LTC HANC VITC LTC ATC Remark No longer listed! SMPTE 291M RP 188/SMPTE 12M 2 Specification unknown! RP 188 led to different im plementations! It is strongly recommended to implement ATC according to SMPTE 12M2! Introduction There are four transport methods of time code known (regarding only “12M” time codes, so not dealing with MPEG, film, digital audio, midi etc.): LTC VITC DVITC ATC Transported as a serial (analogue audio) signal independent of any video signal. Inserted in an active line within the VBI of an analogue video signal. Similar to the VITC inserted in an active line within the VBI of a digital video signal. Ancillary data packets carried in the ancillary data space of a digital data stream. Remarks regarding the DVITC: There is no specification of DVITC for HD digital video! ATC can be used for SD digital video as well. For HD digital video ATC should be used. ATC can be of type ATC_LTC and ATC_VITC. The ancillary data spaces of a digital television data stream are HANC in the horizontal blanking area and VANC in the vertical blanking interval. HANC:All lines after EAV but before SAV. VANC: In the vertical blanking region after SAV but before EAV. Ancillary data packets should not be located in the lines identified as a switch point – defined by SMPTE RP 168. Format of Ancillary Time Code Packets SMPTE 291M defines the format for a type 2 ANC packet. 16 User Data Words consist of time code data and the type of time code, i.e. LTC or VITC or further user defined time codes. For HD digital video the ANC packets shall be carried in the Y stream. ATC according to SMPTE 12M2 is applicable to 8, 10, or 12bit television systems. www.alpermann-velte.com/faq_e/e_atc.html 1/2 faq. inserting the ATC_LTC in the first field. November 2009. 50/60 frames: Something New and Special ATC_VITC: In detail the ATC_VITC consists of two types.com/faq_e/e_atc. Interlaced: Progr. line 10. these converter modules are able to convert the ATC_LTC to an ATC_VITC. PCIHD/PCIeD/PCIeHD from version 7.html 2/2 . The first frame of the frame pair receives the new time address which then will be repeated at the second frame. Others: You can download the latest versions from: Software Please don’t hesitate to contact Alpermann+Velte if you have any ATC problems. We would like to help analyzing this problem. but the VITC marks the individual frames using the field flag. This method will keep the time addresses and add the advantage of the field flags. In interlaced video formats the transmission rate may be once a frame or every field. Ancillary Time Code (ATC) according to SMPTE 12M-2 Recommendations of SMPTE 12M2 Location for ATC in HD video: Location for ATC in SD video: ATC_VITC in HANC.168. so for progressive systems running at greater than 30 framespersecond each time code count references a frame pair. and the internal encoder or decoder handles the VITC1 and VITC2 type.. this now has changed: DT/DV and HT/HV from version 2.19. line 9. If only ATC_LTC is present in a progressive video system with frame rate greater than 30 frames per second or in interlaced systems. This concerns our RUBIDIUM modules DT/DV and HT/HV. We decided to offer the onceaframe method as a default. in VANC as early as possible from line 9 of 625/50/I and line 13 of 525/59.5/9/13 Alpermann+Velte time code and ancillary data systems. ATC_LTC: The SMPTE 12M2 gives not a clear recommendation about the transmission rate of the ATC_LTC: „.alpermann-velte. Now only ATC_VITC will be presented... Evaluating this flag enables a time code reader or inserter to identify the first or second frame. After an update please take care using only the latest configuration tools and drivers. Implementations of VITC1 and VITC2 should be used to distinguish between the fields of interlaced formats and the frames of a frame pair of progressive formats.0. Counting frames up to 50 or 60 is not provided.. Older versions of the RUBIDIUM modules DT/DV and HT/HV as well as our PC boards PCIHD. Deutsch | Home | About us | Sitemap www. PCIeD and PCIeHD have treated VITC1 and VITC2 as separate time codes. together with the field mark flag. VITC1 and VITC2. The user may select the everyfield method by activating the „All Fields“ checkbox. at least once a frame . ATC_LTC > ATC_VITC: The HT and HV modules are our time code converters in HD digital video systems.“. Apart from this type definition the payload of both types is identical.94/I. ATC_LTC in HANC. With LTC it is not possible to distinguish between the frames of a pair. 25/30 frames: Progr. thus making the individual frames/fields distinguishable. October 2009.
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