Advanced Time Code Setup

chip tcDrastic products like DrasticDDR and MediaNXS support a wide variety of time code sources.  The default selectable configurations will usually be the correct ones for most standard workflows.  For other workflows, the time code sources need to be more finely controlled.  This document covers the time code source precedence setup for Drastic products

Basic Time Code Setup

For most situations the recording is only after one time code.  The simplest way to set this up is to run the MediaNXS interface, select the Setup tab and select the time code source from the pulldown menu.  This menu gives you the following choices:

  • RP-188 LTC
  • RP-188 VITC
  • SMPTE (LTC) External
  • VITC
  • RP-215
  • IRIG
  • Time Of Day
  • Absolute Frame Count

Selecting any of these will reset the advanced precedence setups below to favor that time code input.  If it is not present, it will then look for other valid time code sources in a reasonable order.  Please note, due to the design of some boards, when RP-188 is selected external SMPTE may not be available as a secondary source, and vice versa.

 
tc pulldown 

 

Advanced Time Code Setup

The time code source precedence can be set up on a per channel basis using the DDRConfig application.  Run DDRConfig and go to the the Advanced tab.  Open the VVW branch and the channel branch you want to change (usually Internal0).  There will be a series of entries for LTC source and VITC source.  They are separate because Drastic software tries to maintain two time codes for each video stream.  Here they are with their defaults:

  • LTCSourcePrecedence0 - 0x20 / 32
  • LTCSourcePrecedence1 - 0x40 / 64
  • LTCSourcePrecedence2 - 0x02 / 2
  • LTCSourcePrecedence3 - 0x04 / 4
  • LTCSourcePrecedence4 - 0x01 / 1
  • LTCSourcePrecedence5 - 0x10 / 16
  • VITCSourcePrecedence0 - 0x20 / 32
  • VITCSourcePrecedence1 - 0x40 / 64
  • VITCSourcePrecedence2 - 0x01 / 1
  • VITCSourcePrecedence3 - 0x10 / 16
  • VITCSourcePrecedence4 - 0x02 / 2
  • VITCSourcePrecedence5 - 0x04 / 4

The 'Precedence' sets what time code source will be searched first for a valid time code.  Once one is found, the search is ended for that type (VITC or LTC) and that time code is used.  The possible time code sources are:

  • 0x01 / 1 = In Video RP-188 VITC (Hanc time code)
  • 0x02 / 2 = In Video RP-188 LTC (Hanc time code)
  • 0x04 / 4 = External SMPTE/LTC time code
  • 0x08 / 8 = Time of day (internally derived)
  • 0x10 / 16 = VITC in VANC
  • 0x20 / 32 = IRIG time code
  • 0x40 / 64 = RP-215 (KLV in VANC)

So in the default case, LTC would look for IRIG, RP-215, RP-188L, SMPTE, RP-188V, VITC.  The VITC would look for IRIG, RP-215, RP-188V, VITC, RP-188L, SMPTE.  The order is entirely up to the user, but each source should only appear once in each list.