If We Could Turn
Back Timecode:
Finding a Way to Better
Ancillary Data

Presented by Kelly Haydon and Benjamin Turkus
October 26th, 2018 | British Film Institute | London
No Time to Wait 3rd Annual Conference

10:26:20;18

What do Cher and Timecode have in Common?
1. They’ve been around forever
2. Their relevance is constantly questioned

The Timecode Problem"...If [capturing timecode] were possible(and not super hard) to do in every
instance, I probably would. I think thereason it isn’t always captured is more thefact that it’s a huge pain in the ass with ouravailable tools." - Michael Angeletti, Stanford
Media Preservation LabThe Timecode Problem●

Most preservation container formats have not been developed tocontain the totality of ancillary data from an analog signal (theAS-07 working group is progressing on this specification for theMXF container format).

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Proprietary capture software often does not interpret timecodeas a stream which does not preserve the signals native
discontinuity. Rather, software will only capture the firsttimecode stamp and either lay down a bogus continuous track orjust capture the timecode of the first frame.

●Preservationists lack community-supported resources forcapturing and understanding timecode.
Cher is so over it

is Timecode?
WhatWhat
is TimecodeAnyway?

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01:04:24;40“Adopted in the 1960s by the Society of Motion Picture and Television Engineers,
SMPTE timecode is an industry standard frame numbering system that assigns aspecific number to each frame of video in hours, minutes, seconds, and frames
format.” (The Professional Video Sourcebook, BH Photo/Video).

Brief Timecode Timeline●1956 - videotape is here, yay! But editors can’t see the framelines; the cut and splice method is adapted upon but
imprecise and tedious.

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1960s - electronic splicing systems are introduced but
required the editor to search for a desired splice point andmark it with an electronic tone, also a tedious and imprecise
process.

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1967, EECO introduced the timecode synchronization
system to the industry and in 1969, SMPTE/EBU
standardized the timecode that we know today. Each frameof video has its own unique timecode and linear tape-to-tapeediting is efficient AF.

Source: “Time Code Basics,” Anonymous, American Cinematographer; Mar 1983;
64, 3; ProQuest pg. 23

Brief Timecode Timeline
Timecode becomes an integral part of productions workflows recorded on both film andtapeEdit Decision Lists (logs timecode of correspond to the final cut).

Timecode in Production
Video production workflows often logged thereel number of the tape shot in a day’s work.
Tape 1 - Start Timecode: 01:00:00;00
Tape 2 - Start Timecode: 02:00:00;00
Tape 3 - Start Timecode: 03:00:00;00

Characteristics of Timecode
Three characteristics to look out for when assessing your timecode*●

Is it VITC or LTC timecode?

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Is it Drop Frame or Non Drop Frame?

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Is it Continuous or Discontinuous?

*DV Time (DV timecode captured via firewire) and DAT are not included in this timecode discussion .

Characteristics of Timecode: VITC & LTC
Longitudinal TimeCode (LTC)

Vertical Interval TimeCode (VITC)

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The earlier of the two timecode types
Usually (but not always) recorded on audio
track 2.
Prone to drift, read errors, and cannot be readat fast speeds.
Listen to what ltc “sounds” like:
https://www.youtube.com/watch?v=zjH0RFV206M●●

VITC is integrated into the video track of thetape which resolves a number of problems
found with LTC
Provides indexing resolution down to thevideo field; this means VITC timecode can beread at all speeds the video is played back at
Frees up the 2nd audio channel for recording

Audio Track 2
Audio Track 1

Video Track

Video Track

Control Track

Control Track

Timec

ode

Audio Track 2 (Timecode)
Audio Track 1

Source: “Time Code Basics,” Anonymous, American
Cinematographer; Mar 1983; 64, 3; ProQuest pg. 23

NOTE: Track configurations can vary by format. Images
are non-format specific examples

Characteristics of Timecode: NDF & DF (it’s anNTSC thing)●Drop Frame [DF] and Non-Drop Frame [NDF] are distinguished by the colon orsemi-colon present before the frame count:

Drop Frame:
HH:MM:SS;FR (01:01:01;01)
Non Drop Frame: HH:MM:SS:FR (01:01:01:02)●●

Simply two different ways of labeling a frame. Drop Frame timecode accommodates
the 29.97fps framerate of color, introduced after the 30fps was already established
for monochrome.
“When an American TV frame-rate video production must be edited to actual clock
time, Non Drop Frame timecode must be used. If staying in time with an actual clock
is not important, especially on short video productions like commercials, the bastard
29.97 fps Drop Frame timecode is often used.” - Shawn Amaro, “How to Use Drop
Frame or Non-Drop Frame.”

Source: “SMPTE EBU”, Phill Rees:
https://drive.google.com/drive/folders/1fTTe27RhP1G_v-C8Acd_9L_ItBrg1xIs

Characteristics of Timecode:
Continuous & Discontinuous●Continuous timecode is an unbroken clocking moving forward from the first frame tothe last.

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Discontinuous timecode occurs when a recording abruptly stops and starts again.
Discontinuous timecode is common in recordings not made within strict broadcast
workflows: video art, independent media, home movies

01:04:24;36

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xx:xx:xx;xx

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So why should archivists care about Timecode?
Legacy timecode (or “time code”) is a tool for:●Restoring, finishing, or rebuilding film andvideo works based on existing edit
decision lists (either paper based orsoftware generated)●

Identify the placement of a camera roll inan array of tapes (tape 1, tape 2, tape 3,etc.)●

Contextualizing the support
documentation found in a collection (andraising the research value of that
documentaion)●

Finding important/interesting material
amid large quantities of media based on
available documentation

1979 edit decision list for a production recorded on Umatic tape(VTOldboys.com)

Timecode: The Original Trash Fire

Capturing Timecode: A New Bare Minimum?

$145$10< $1,000$450

What are the issues regarding timecode? Source recordings may have multiple
timecodes: vertical interval timecode (VITC), linear timecode (LTC), and more.
Some are present on purpose, others by accident; some may have good integrity
and continuity, others may be discontinuous. Any or all of these timecodes may
provide forensic help for future researchers. A legacy timecode may be keyed toold documents like tape logs, may provide clues about the older source tapes thatwere assembled to create the video program you are now preserving, and may (aswith footage of NASA space vehicle launches) represent elapsed time that can becorrelated to other data streams. In many cases, this is data you do not want tolose.
Carl Fleischauer, AMIA-L, 2014
https://lsv.uky.edu/scripts/wa.exe?A2=ind1402&L=AMIA-L&D=0&P=218059

When Timecode Makes U Wanna Scream●●●●LTC does not match VITC
LTC is DF and VITC is NDF.
LTC is inconsistent or garbled.
User bit code if present isinconsistent.
● VITC changes line assignment ordrops out completely in a single tape.
● Time code in the picture [BITC] does
not match LTC or VITC.
David Crosthwait, AMIA-L, 2014
https://lsv.uky.edu/scripts/wa.exe?A2=ind1402&L=AMIA-L&D=0&P=224872

The Problem of Timecode Revisited
The challenges of transmitting, through a digitization set up, the different
types of timecode, messy or not, that could be recorded onto a tape
The work-in-progress discussion of how best to store these different types oftimecode within a digital video file

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The complexities of timecode as recorded onto different video formats (what’s possible;
what’s common; what’s rare)
The complexities of choosing the right decks and connections to capture
Capture card differences/issues
File format compatibility with all of this nonsenseMatroska, timecode, and side data
VBI (Vertical Blanking Interval) and ANC (Ancillary Data)
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●Timecodes (LTC, VITC, ATC)
Captions(North American CEA-608, CEA-708,
European and Australian WSS/Teletext, Japanese
ARIB B37)
Recording Information
Bar and pan/scan data
Camera acquisition dynamic metadata
Audio Metadata
Film Transfer and Video Production Information

Thomas Edwards, “RTP Payload for SMPTE ST 291 Ancillary Data,”
https://datatracker.ietf.org/meeting/92/materials/slides-92-payload-2

Decklink Duo 2 DramaIn FFmpeg/vrecord, we can now:
1.
2.

store a correct first frame timecode stamp within our files; andstore vrecord-produced sidecar txts that will log all of the analog timecode values,
continuous or not, as we wait for the larger Matroska side data advancement

Format

SMPTE LTC

SMPTE VITC

CaptureRecommendation

Additional
Considerations

EIAJ-1 & EIAJ-2

n/aU-matiC

Serial (RS-422)
LTC audio as audio

Mostly late generation
VTRs (VO and BVU series)
with timecodegenerator/readers; someaftermarket modifications;
LTC on audio or address
track

1” Type C

Serial (RS-422)/LTC audio
as audio

LTC (audio CH3) mostcommon

S-VHS

Serial (RS-422)
LTC audio as audio

No separate address trackfor LTC; typically CH2

Betamaxn/aBetacam Family

SDI

Video8 Hi8n/a

No SMPTE timecode, but
Sony RCTC (rewritableconsumer timecode)

Trust your machines (but read your manuals)

Sony Service Manuals for BVU-950, SVO-5800, and BVW-D75

Puzzling Over the Permutations

The New Discontinuity (w/ vrecord)

Time After Timecode? If Only!
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MKV side data (for timecode/s and lots ofother stuff)
FFmpeg & decklink ability to read multiple
timecodes
Format-by-format decision tree, withrecommendations for diff scenarios (a.k.a.
how to set yourself up for success)Rethinking workflows and digitization racks
Automated audio LTC conversion (sometools out there)
User Bits (super fun, not discussed at all inthis prez)
More vrecord testing and tweaking

timecode