IEC TS 62312-1-1:2018

IEC TS 62312-1-1 ®
Edition 2.0 2018-11
REDLINE VERSION
TECHNICAL
SPECIFICATION
colour
inside
Guideline for synchronization of audio and video –
Part 1-1: Measurement methods for synchronization of audio and video
equipment and systems – General

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IEC TS 62312-1-1 ®
Edition 2.0 2018-11
REDLINE VERSION
TECHNICAL
SPECIFICATION
colour
inside
Guideline for synchronization of audio and video –

Part 1-1: Measurement methods for synchronization of audio and video

equipment and systems – General

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.01 ISBN 978-2-8322-6218-4

– 2 – IEC TS 62312-1-1:2018 RLV © IEC 2018
CONTENTS
FOREWORD . 4
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 7
4 Measuring conditions . 8
4.1 General conditions . 8
4.1.1 Power supplies . 8
4.1.2 Environmental conditions . 8
4.2 Specific conditions . 8
4.3 General settings. 8
4.4 Specific settings . 9
5 Measurement methods . 9
5.1 General block diagram . 9
5.2 Test signal source and test signal . 9
5.2.1 General . 9
5.2.2 Signal generator . 10
5.2.3 Test disc . 10
5.3 EUT . 10
5.3.1 Equipment . 10
5.3.2 Compound equipment . 12
5.4 Measuring instruments . 12
5.4.1 General . 12
5.4.2 Measurement of signal. 13
5.4.3 Measurement of reproduced signal . 13
5.4.4 Specific requirement . 13
Annex A (informative) Assessment of the result of measurement . 14
Annex B (informative) General measurement and test method of audio latency . 15
B.1 Measurement . 15
B.2 Test signal . 15
B.3 Test method . 15
Bibliography . 16

Figure 1 – General block diagram for measurement . 9
Figure 2 – Audio and video device . 10
Figure 3 – Source device . 11
Figure 4 – Display device . 11
Figure 5 – Recorder device . 12
Figure 6 – Compound equipment . 12
Figure 7 – Measurement of reproduced signal . 13
Figure B.1 – block diagram of test. 15

Table B.1 – Frequency range of test signal . 15

– 4 – IEC TS 62312-1-1:2018 RLV © IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDELINE FOR SYNCHRONIZATION OF AUDIO AND VIDEO –

Part 1-1: Measurement methods for synchronization of audio
and video equipment and systems – General

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition. A vertical bar appears in the margin wherever a change
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The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 62312-1, which is a technical specification, has been prepared by technical area 11:
Quality for audio, video and multimedia systems, of IEC technical committee 100: Audio,
video and multimedia systems and equipment.
This second edition cancels and replaces the first edition published in 2008. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) new Annex B informs of general measurement and test method of audio latency;
b) comments from SMPTE (including small technical issues).
The text of this Technical Specifications is based on the following documents:
Enquiry draft Report on voting
100/3048/DTS 100/3105/RVDTS
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The list of all the parts of IEC 62312, published under the general title Guideline for
synchronization of audio and video, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

– 6 – IEC TS 62312-1-1:2018 RLV © IEC 2018
INTRODUCTION
Audio and video equipment processes or reproduces the input signals of audio and video,
then outputs these signals in various forms. Audio and video equipment needs time to
process or reproduce the input signal. This time depends on the signal format, the
architecture of the equipment and the design of the equipment. Hence, audio and video
equipment may have different output delays for audio and video signals, and this causes
unsynchronised audio and video outputs.
This Technical Specification is the general part of the measurement method for that time
difference between audio and video outputs. The other parts of IEC /TS 62312-1 describe
specific measurement methods for specific audio and video equipment.

GUIDELINE FOR SYNCHRONIZATION OF AUDIO AND VIDEO –

Part 1-1: Measurement methods for synchronization of audio
and video equipment and systems – General

1 Scope
The IEC 62312 series gives guidelines for methods of synchronization of synchronizing audio
and video.
This part of IEC 62312-1 describes general measurement methods for the synchronization of
audio and video equipment.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC TS 62312-2:2018, Guideline for synchronization of audio and video – Part 2: Methods for
synchronization of audio and video systems
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms and definitions apply. Also the terms
and definitions given in IEC 62312-2 apply.
3.1
EUT
equipment under test
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.2 Abbreviated terms
EUT equipment under test
– 8 – IEC TS 62312-1-1:2018 RLV © IEC 2018
4 Measuring conditions
4.1 General conditions
4.1.1 Power supplies
4.1.1.1 Voltage
The supplied AC power voltage shall be the fixed value of the region where the equipment
under test is used. The supplied DC power voltage shall be the fixed value specified by the
manufacturer. The tolerance shall be within ±1 % in both cases. If this tolerance does not
affect the results of measurement, the tolerance can be within ±5 %.
4.1.1.2 Frequency
The frequency of the AC power supply shall be 50 Hz or 60 Hz and the fluctuation shall be
within ±2 %.
4.1.1.3 Waveform distortion
4.1.1.3.1 AC power supply
The waveform of the AC power supply shall be a sine wave in which the harmonic content is
2 % or less.
4.1.1.3.2 DC power supply
The ripple voltage shall be 0,1 % or less.
4.1.2 Environmental conditions
4.1.2.1 Environmental air condition
The environmental conditions for measurements shall be:
+15
Ambient temperature: 20 °C
-5
Relative humidity: 60 % ± 15%
Air pressure: 96 kPa ± 10 kPa
4.1.2.2 Warm up
The equipment under test shall be powered on 5 min before starting the test. It may be zero if
the warm up does not affect the results of the measurement.
4.1.2.3 Initialization
The equipment under test shall be initialized before starting the test.
4.2 Specific conditions
If specific conditions are required for the measurement of the equipment, those conditions
shall be specified.
NOTE The other subparts of IEC 62312-1 specify IEC TS 62312-2 specifies the measurement method for the
specific equipment; the special conditions may be are specified in that part.
4.3 General settings
General settings for equipment shall be set to the default setting, which is specified by the
manufacturer, normally the centre position. If there will be is no special indication and about

the functions that affect the results of measurement of sychronization, all of the controllers
shall be switched off.
4.4 Specific settings
If specific equipment has its own specific settings, it shall be set to have the results of
measurement regarding the specific settings. The other subparts of IEC 62312-1 specify
specific settings for specific equipment.
If a piece of equipment has its own specific settings, it shall be set to have the results of
measurements related to those specific settings.
5 Measurement methods
5.1 General block diagram
Inputs Outputs
Test
Video Video
Measuring
EUT
signal
instruments
source
Audio Audio
IEC
Figure 1 – General block diagram for measurement
The test signal source provides the reference audio and video signal. There is either no time
difference between them or the difference is specified. These audio and video test signals are
applied to the EUT in the appropriate method for each EUT. The EUT reproduces or
processes these test signals and outputs the audio and video signals. The measuring
instruments measure the output from the EUT and measure the time difference between audio
and video outputs from the EUT.
The test signal source outputs the signal in a format that should be suitable for the EUT to
process.
In the case that the EUT, such as an audio amplifier, reproduces no video signal, general
measurement and the test method of audio latency is available as described in Annex B.
5.2 Test signal source and test signal
5.2.1 General
The test signal source provides audio and video test signals as a reference signal for
measuring. The content, format and media of the test signal are different depending on the
EUT.
The basic format of the test signal content consists of synchronized audio and video signals
that are used as a reference for synchronization and are processed or reproduced by the EUT.
The EUT outputs the resulting signal to the measuring instruments. The output signal should
be detectable and be able to be measured by the measuring instruments. To conform to this
requirement, the test signal content should be made suitable for the measuring instruments.
The form of the test signal is an electrical signal or a signal recorded on media. The format
and media of the test signal should be appropriate for the EUT. This would normally be the
default format and media appropriate to the functionality of the EUT.

– 10 – IEC TS 62312-1-1:2018 RLV © IEC 2018
5.2.2 Signal generator
Where a signal generator is applied to an EUT that has a signal input, the format of the output
signal of the signal generator should be appropriate for the EUT. The signal will be input
through an appropriate signal interface on the EUT.
5.2.3 Test disc
Where a test disc is applied to an EUT that is a disc player, the test disc format should be
appropriate for the EUT.
5.3 EUT
5.3.1 Equipment
5.3.1.1 General
In this document, the EUT is an audio and video device that consists of audio and video units.
Each unit includes latency and delay. The model of the audio and video device is defined in
IEC TS 62312-2.
Figure 2 shows a simplified model of the audio and video device based on the definition of
IEC TS 62312-2.
Audio and video device
Inputs Outputs
TL + TD
Video v v Video
t
t + TL + TD
1 v v
TL + TD
a a
Audio Audio
t + TL + TD
1 a a
IEC
Figure 2 – Audio and video device
The total latency and the delay of the audio and video device are defined.
TL : total latency of video
v
: total delay of video
TD
v
TL : total latency of audio
a
TD : total delay of audio
a
Latency and delay are defined for this series, IEC 62312, in Clause 3 of IEC TS 62312-2:2018.
The audio and video device reproduces or processes the input signal, and this causes delay
and latency. From the input to the output, the total delay and the total latency are caused in
each of audio and video signals. The audio and video signals are input to the audio and video
device at the time t , the total latency and delay are added to this to form the audio and video
output signals.
The outputs from the source device are audio and video signals in analogue or digital form.
Between the input and the output, the total delay and the total latency are induced in each of
the audio and video signals. The audio and video signals are input to the audio and video
device at the time t ; the total latency and delay are added to the time t .The outputs from the
1 1
source device are audio and video signals in analogue or digital form.

The purpose of this Technical Specification is measurement of the total latency and delay; the
assessment of them is specified by the other specifications as described in Annex A.
5.3.1.2 Category of audio and video device
5.3.1.2.1 Source device
Audio and video devices are categorized into specific types of devices.
Figure 3 shows the source device and the signal source that is the input to the source device.
The signal source can be in various forms. In the case of a disc player, the disc is the signal
source. In the case of a tuner, the received and decoded broadcasting signal is the signal
source.
Source Device Outputs
Video
Video
t + TL + TD
TL + TD
1 v v
v v
Signal
t
Source
Audio
TL + TD
t + TL + TD
a a
1 a a
Audio
IEC
Figure 3 – Source device
5.3.1.2.2 Display device
Figure 4 shows the display device. The outputs from this device are audio and video signals
reproduced as sound and visual images realized by a display unit and speakers.
Display device
Inputs
t + TL + TD
1 v v
Video
Video driver
Display unit
TL + TD
v v
t
Audio
TL + TD Speakers
Audio driver
a a
t + TL + TD
1 a a
IEC
Figure 4 – Display device
5.3.1.2.3 Recorder device
Figure 5 shows the recorder device; the audio and video signals are recorded on the storage
and these signals are played and then output. The total delay and latency are the sums of
each of the total delay and latency of the recording part and the playback part, as identified by
suffix R for the recording part and P for the playback part. In order to measure the recording
part delay, the monitor outputs are used.

– 12 – IEC TS 62312-1-1:2018 RLV © IEC 2018
Inputs Outputs
Recorder device
Recording part Playback part
Video Video
(TL + TD )R Storage (TL + TD )P t + TL + TD
v v v v 1 v v
t
Audio
Audio
(TL + TD )P t + TL + TD
(TL + TD )R a a 1 a a
a a
Monitor outputs
IEC
Figure 5 – Recorder device
5.3.2 Compound equipment
Equipment may consist of multiple audio and video devices. Generally, the EUT is defined as
the device between the first input and the final output. When it is required to measure the EUT
from the second or later input to before the final output, those inputs and outputs should be
the subject of measurement. Figure 6 shows compound equipment that consists of multiple
(n devices) audio and video devices.
For instance, equipment such as a TV with a video recorder consists of a TV tuner as a
source device, recorder device and display device.
First inputs
Audio and video device 1 First outputs
Video
Video
(TL + TD )1 t + (TL + TD )
v v 1 v v 1
t
Audio Audio
(TL + TD )1
t + (TL + TD )
a a
1 a a 1
…….
n = 1, 2, 3, ….
n th input
Audio and video device n
Final outputs
Video
t + (TL + TD ) +
1 v v 1
Video
(TL + TD )
v v n
~ + (TL + TD )
v v n
Audio
t + (TL + TD ) +
1 a a 1
(TL + TD )
Audio
a a n
~ + (TL + TD )
a a n
IEC
Figure 6 – Compound equipment
5.4 Measuring instruments
5.4.1 General
The audio and video device outputs audio and video signals with the total values of latency
and delay as shown in Figure 2. The measuring instruments should have a capability to
measure the timing of the output signal that is a processed or reproduced signal of the input
signal. The measuring instruments measure the value of the difference between them, or
calculation gives the difference, the value is:

T = (t + (TL + TD )) – (t + (TL + TD )) = (TL + TD ) – (TL + TD )
d 1 v v 1 a a v v a a
where
T is a time value that indicates the total latency and delay of the video against the audio,
d
expressed in ms.
5.4.2 Measurement of signal
The forms of output signals are analogue or digital. When it is in analogue form, the
measuring instruments are a video analyser, audio analyser or oscilloscope. When they are in
digital form, they are signals in a digital interface. The signal format of a digital interface will
be a specific format depending on each interface format. The measuring instruments should
have a capability to measure these signals.
5.4.3 Measurement of reproduced signal
To measure the output of the reproduced audio and video signals, measuring instruments
should have a capability to measure sound and visual images. Figure 7 shows the
measurement of the reproduced signal.
To measure sound, an acoustic to an electrical (A/E) transducer is applied. If the acoustic
spatial delay is out of the subject of should be considered for the measurement result, the
electrical signal of the audio is applied to measure sound.
To measure the visual image, an optical to electrical (O/E) transducer is applied. The O/E
transducer senses the visual image on the display unit. Which part of the visual image should
be the subject of the measurement depends on the test signal contents.
Oscilloscope or other measuring instruments are used to measure these converted electrical
signals.
Display device
To measuring
Visual image
instruments
Display unit O/E
Video driver
Speakers A/E
Audio driver
Sound
Electrical signal
IEC
Figure 7 – Measurement of reproduced signal
5.4.4 Specific requirement
The form and format of the audio and video outputs from the EUT vary depending on the kind
of EUT. The content of the output from the EUT depends on the test signal.
The measurement instrument should have a capability to measure the outputs from the EUT.

– 14 – IEC TS 62312-1-1:2018 RLV © IEC 2018
Annex A
(informative)
Assessment of the result of measurement
The r
...