www.smpte.org  

   Paul  Briscoe  Manager,  Strategic  Engineering,    Harris  Broadcast  

Network-­‐Based    Timing  and  Synchroniza�on  

   

“Genlock  in  the  Cloud”    

IEEE    Mee�ngs,  Victoria,  BC.  May  14th,  2013  

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Sync  and  Timing  in  Media  

Why do we synchronize things? Video   Switching, Mixing   Use Genlock – Black Burst or TLS

What about digital audio?   DARS (AES3 / AES11)

What about time?   Timecode SMPTE ST-12

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Synchroniza�on  in  Media  

3  

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System  Synchroniza�on  

4  

   

 

Studio A

Studio B Edit 1

OB Truck

Edit 2 Graphics

MCR Feeds

Master Generators

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System  Synchroniza�on  

5  

   

Studio A

Studio B Edit 1

OB Truck

Edit 2 Graphics

MCR Feeds

Master Generators

 

Black, DARS, Timecode

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System  Synchroniza�on  

6  

   

Studio A

Studio B Edit 1

OB Truck

Edit 2 Graphics

MCR Feeds

Master Generators

 

Black, DARS, Timecode

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Distribu�on  System  

7  

Master  SPG  

Autochangeover  

First Floor Second Floor Third Floor Fourth Floor Fifth Floor Sixth Floor Seventh Floor

NW Quad SW Quad SE Quad SW Quad

STD 12 STD 13 STD 14 STD 15 STD 16

Master Control / Central Equipment Fourth Floor SW Quad STD 14

Studio Gear

Studio Gear

Slave  SPG  

Master  SPG  

Studio Gear

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Distribu�on  System  Layers  

8  

Master  SPG  

Autochangeover  

First Floor Second Floor Third Floor Fourth Floor Fifth Floor Sixth Floor Seventh Floor

NW Quad SW Quad SE Quad SW Quad

STD 12 STD 13 STD 14 STD 15 STD 16

Master Control / Central Equipment Fourth Floor SW Quad STD 14

Studio Gear

Studio Gear

Slave  SPG  

Master  SPG  

Studio Gear

Master  SPG  

Autochangeover  

Slave  SPG  

Master  SPG  

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What  do  References  Deliver?  

Frequency   Different for each signal type used   Varying degrees of tolerance

Phase   Known phase references

  VSync, HSync - ST318 BlackBurst   Audio block, frame - AES3 /

AES11   Time of Day - ST12 Timecode   Date - ST309

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Genera�ng  Signals  

10  

  Logic state machines generate signals from a clock (timebase)

  Operate at framerate modulus   Generate the same thing over and over

and over   Known rate, but arbitrary phase =

asynchronous   This is every piece of free-running gear

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Genera�ng  Signals  -­‐  Freerunning  

11  

  Local high-precision oscillator generates clock   SMPTE Frequencies

  Logic state machines generate signals

  Free-running

TCXO  

Signal  Generator   SDI

Clock

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Genera�ng  Locked  Signals  

12  

  Frequency Lock – clock for signal generator

  Phase Lock – vertical (and horizontal) alignment   Achieved by resetting the generator to an

anchor   Vertical Sync is a natural anchor for video

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Genera�ng  Locked  Signals  

13  

  Sync Separator extracts H and V   H drives PLL to generate locked timebase   V resets signal generator to known phase   H and V knobs adjust timing relative to

reference

Logic  

Signal  Generator  

Phase-locked loop

Clock

Sync  Separator  

Black Burst

SDI H

V

TCXO  

V Reset

H V

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Sync  and  Timing  Systems  Today  

So what’s the problem with that?   Ancient technologies (from a simpler

time)   Mix of analog and digital-ish signals   Serious modern functional limitations

  Don’t support > 60 fps, VFR   BlackBurst ≠ HDTV   Require multiple distributions   CAPEX, OPEX   nailed down architectures

  It’s 2013, there must be a better way!

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IP  Networks  

15  

Touch most equipment today Easy to deploy, modify Remotely / centrally managed Security provisions

The new core infrastructure for media Might be a good way to distribute references

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New  Opportunity  

16  

   

 

Studio A

Studio B Edit 1

OB Truck

Edit 2 Graphics

MCR Feeds

Master Generators

 IP Network

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Network-­‐Delivered  Reference  Requirements  

17  

Deliver references over IP network Provide capability of legacy systems Deterministic behaviour Provide open platform for future

Signals (transports) Formats (essence)

Use COTS technology wherever possible

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Network  Performance  

18  

Non-deterministic   Can’t predict when things happen   Traffic all shares the road   Message delays are variable

Jitter! Things get lost We need a core technology that overcomes this!

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One  Possible  Solu�on  

19  

  NTP   Works on IP networks   Deterministic   Delivers time   Not enough

performance   millisecond-class

time accuracy

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Enter  IEEE  1588  PTP  

20  

Network-based Precision Time Protocol Delivers precision time to many slaves   Spans hundreds of years   Sub-nanosecond granularity   Delivered over IP network   Can be globally locked   Can co-exist with other traffic

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1588  Span  and  Granularity  

21  

1 Sec

ond

1 Minu

te

1 Hou

r

1 Day

1 Mon

th

1 Yea

r

1 Milli

seco

nd

1 Micr

osec

ond

1 Nan

osec

ond

SDI Video

12M Timecode

Calendar

NTP

AES Audio

Composite Video

IEEE1588

GPS Native

Nanoseconds – 32 bits (1 ns)Whole Seconds - 32 bits (~136 years)

64-bit binary time count

LSB

1 Hz(PPS)

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1588  Span  and  Granularity  

22  

1 Sec

ond

1 Minu

te

1 Hou

r

1 Day

1 Mon

th

1 Yea

r

1 Milli

seco

nd

1 Micr

osec

ond

1 Nan

osec

ond

SDI Video

12M Timecode

Calendar

NTP

AES Audio

Composite Video

IEEE1588

GPS Native

Nanoseconds – 32 bits (1 ns)Whole Seconds - 32 bits (~136 years)

64-bit binary time count

LSB

1 Hz(PPS)

Us  

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Frequency  from  Time  

23  

PTP delivers time, not frequency Frequency is transferred by comparing local timekeeping to incoming “At the tone, the time….”

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Signals  From  Time  

24  

  Time = signal phase   Pick an Epoch (instant in time)

  Some past date and time (PTP Epoch)

  Define alignment of signals to that instant   Can predict future phase of any signal

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Timebase  Genera�on  from  PTP  

25  

  PTP Slave has locked timebase

  SMPTE Frequencies are cross-synthesized to required frequency  Many methods  Low cost  High accuracy

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Anchor  Genera�on  from  PTP  

26  

Signal  Generator  

Clock

SDI

V Reset

Local  Running  Time  Count  Live Running Time

Compare  Calculate  Next  Ver�cal  

Equal

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Full  Genlock  from  PTP  

27  

Logic  

Signal  Generator  

Cross-synthesis

Clock

SDI

TCXO  

V Reset

H V

Local  Running  Time  Count  

Local  Timebase  Oscillator  

Live Running Time

10 MHz SMPTE Frequency

Compare  Calculate  Next  Ver�cal  

Equal

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Dual-­‐Mode  Genlock  Equipment  

28  

Logic  

Signal  Generator  

Cross-synthesis

Clock

SDI

TCXO  

V Reset

H VLocal  Running  Time  Count  

Local  Timebase  Oscillator  

Live Running Time

10 MHz

Calculate  Next  Ver�cal  

Equal

Logic  

Phase-locked loop

Sync  Separator  

Black Burst

H

V

TCXO  

Compare  

P  PTP

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Some  Limita�ons  

29  

  Within a system, timing is deterministic   All running from same master

  Between systems, timing is non-deterministic   Can achieve frequency lock   Phase between systems is manual   That’s why we have frame

synchronizers

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Determinis�c  Behaviour  

30  

  Establish alignment of all signals at Epoch   Yellow and blue represent two different

SMPTE signal types   Conveyor belt is PTP timebase   Signals phase (anchor) aligned at Epoch

t = 0A

B

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Determinis�c  Behaviour  

31  

  At some future time (t=X)   Signals will have different phases   Each can be calculated from Epoch

t = XA

B

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Determinis�c  Behaviour  

32  

  External reference turns belt (GPS)   Wheel phase is

predictable between systems

  Reference can be GPS, other GNSS, big PTP network

GPS(t) = XA

B

GPS

GPS(t) = XA

B

GPS

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Determinism  

33  

Time Counter

Time Counter

Time Counter

Timebase

Signal Generator

Signal Generator

Signal Generator

Signal Y

Signal Z

Signal XEpoch Aware

Epoch Aware

Epoch Aware

Slave Device

Master Generator

Time Transport

Can be derived from external sources

(GPS, etc.)

Signals X, Y and Z will be locked and in phase

Slave Device

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Net  Result  

34  

Can deliver all references over IP network Can have independent systems in phase Can share other traffic on same network   Control, monitoring   File-based transfers   Compressed streaming   Soon live baseband over IP

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History  of  Time-­‐Based  References  

35  

1998 – Leitch (Kupnicki) develops method

Time transport over BlackBurst 1999 – SMPTE not ready to embrace

- That’s OK, we use it inside products 2007 – SMPTE / EBU establish taskforce

Leitch method modernized to use PTP 2010– Basis for SMPTE Standard work

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SMPTE  Ac�vi�es  

36  

33TS Synchronization and Time Labeling Standardization Committee Drafting the ST 2059 Standard Suite

Includes EG and RP   ST 2059-0 Overview of Standard   ST-2059-1 Generation of Signals   ST-2059-2 SMPTE PTP Profile

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Signal  Genera�on  Document  

37  

Specification of SMPTE Epoch Alignment for each signal of interest

References to root standards Formulae for each signal of interest

Direct derivation from time Generation of Time of Day Generation of Timecode

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SMPTE  PTP  Profile  Document  

38  

SMPTE-specific performance criteria   Message Rates   Node Types   Master Selection   Alternate Time Offset

SMPTE-specific metadata   Timecode Helper Data   System Framerate   Miscellaneous System Stuff

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SMPTE  ac�vi�es  

39  

Working Groups   33TS-20 developing sync system

  Signal Generation and Profile   Work nearing completion

  33TS-10 developing new Time Label   Work actively underway

Includes EGs and RPs

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Thank-you! Questions?

More information? Shoot me a note Paul Briscoe pbriscoe@harris.com