ISO/IEC 15938-3:2002/Amd 4:2010

Information technology — Multimedia content description interface — Part 3: Visual — Amendment 4: Video signature tools

Technologies de l'information — Interface de description du contenu multimédia — Partie 3: Visuel — Amendement 4: Outils de vidéosignature

General Information

• Status: Published
• Publication Date: 05-Oct-2010
• ICS: 35.040 - Information coding
• ICS: 35.040.40 - Coding of audio, video, multimedia and hypermedia information
• Technical Committee: ISO/IEC JTC 1/SC 29 - Coding of audio, picture, multimedia and hypermedia information
• Drafting Committee: ISO/IEC JTC 1/SC 29 - Coding of audio, picture, multimedia and hypermedia information
• Current Stage: 6060 - International Standard published
• Start Date: 06-Oct-2010
• Due Date: 13-Jul-2012
• Completion Date: 13-Jul-2012

Relations

• Amends: ISO/IEC 15938-3:2002 - Information technology — Multimedia content description interface — Part 3: Visual
• Effective Date: 26-Jun-2021

Overview

ISO/IEC 15938-3:2002/Amd 4:2010 - part of the MPEG‑7 family - amends the Visual part of the Multimedia Content Description Interface to add video signature tools. It extends the visual descriptor set (color, texture, shape, motion, localization) and the basic descriptor containers (GridLayout, TimeSeries, GofGopFeature, MultipleView) and supporting tools (Spatial2DcoordinateSystem, TemporalInterpolation). The amendment defines a VideoSignature descriptor designed for robust, unique identification of video content (video fingerprinting) and specifies binary codec classification entries for many visual descriptors.

Key topics and technical requirements

• Video signature architecture
  • Frame signature: a 380‑dimensional vector of base‑3 (ternary) values representing intensity relations and statistical operators (mean / first / second order).
  • Words: compact 1‑byte summaries derived from frame signatures; vocabulary of possible words.
  • Bag‑of‑words: group‑of‑frames representation capturing word occurrences over temporal segments to provide temporal robustness (order‑insensitive).
  • Support for single or multiple static spatial regions per frame.
• Visual descriptor families
  • Color: DominantColor, ScalableColor, ColorLayout, ColorStructure, ColorTemperature; supporting tools like ColorSpace, ColorQuantization, IlluminationInvariantColor, GoFGoPColor.
  • Texture: HomogeneousTexture, TextureBrowsing, EdgeHistogram.
  • Shape: RegionShape, ContourShape, ShapeVariation (temporal), Shape3D, Perceptual3DShape.
  • Motion: CameraMotion, MotionTrajectory, ParametricMotion, MotionActivity.
  • Localization: RegionLocator, SpatioTemporalLocator.
  • Face descriptors: FaceRecognition, AdvancedFaceRecognition.
• Signatures and binary codecs
  • ImageSignature and VideoSignature descriptors for robust identification.
  • Classification scheme entries (MPEG7* codec names) and assignment of descriptor IDs (e.g., VideoSignature ID = 34) for binary interoperability.
• Interoperability
  • Use of the codec configuration mechanism defined in ISO/IEC 15938‑1 for signaling video‑specific binary syntax.

Applications and practical value

• Duplicate detection / video fingerprinting for copyright enforcement, content takedown, and automated moderation.
• Large‑scale video search and retrieval in media asset management (MAM), streaming platforms, and search engines using content‑based indexing.
• Forensics and provenance tracking by identifying re‑encoded or edited copies of the same source.
• CDN deduplication and storage optimization by recognizing identical or near‑identical content.
• Surveillance and archival systems for fast lookup of similar video segments.

Who should use this standard

• Multimedia software developers and engineers implementing content‑based indexing or fingerprinting.
• Metadata architects and MAM/CDN vendors integrating MPEG‑7 descriptors.
• Legal/copyright teams and content moderation platforms needing reliable duplicate detection.
• Research groups working on video retrieval, computer vision, and multimedia forensics.

Related standards

• ISO/IEC 15938 (MPEG‑7 family) - overall multimedia content description.
• ISO/IEC 15938‑1 - Systems / codec configuration mechanism referenced for binary signaling.

Keywords: ISO/IEC 15938-3, MPEG-7, video signature, video fingerprinting, visual descriptors, image signature, multimedia content description, color descriptors, texture descriptors, motion descriptors.

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 15938-3
First edition
2002-05-15
AMENDMENT 4
2010-10-15
Information technology — Multimedia
content description interface —
Part 3:
Visual
AMENDMENT 4: Video signature tools
Technologies de l'information — Interface de description du contenu
multimédia —
Partie 3: Visuel
AMENDEMENT 4: Outils de vidéosignature

Reference number
ISO/IEC 15938-3:2002/Amd.4:2010(E)
©
ISO/IEC 2010
ISO/IEC 15938-3:2002/Amd.4:2010(E)
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©  ISO/IEC 2010
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ii © ISO/IEC 2010 – All rights reserved

ISO/IEC 15938-3:2002/Amd.4:2010(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
Amendment 4 to ISO/IEC 15938-3:2002 was prepared by Joint Technical Committee ISO/IEC JTC 1,
Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia
information.
© ISO/IEC 2010 – All rights reserved iii

ISO/IEC 15938-3:2002/Amd.4:2010(E)
Information technology — Multimedia content description
interface —
Part 3:
Visual
AMENDMENT 4: Video signature tools
Replace 1.2 with:
1.2 Overview of Visual Description Tools
This part of ISO/IEC 15938 specifies tools for description of visual content, including still images, video and
3D models. These tools are defined by their syntax in DDL and binary representations and semantics
associated with the syntactic elements. They enable description of the visual features of the visual material,
such as color, texture, shape, motion, localization of the described objects in the image or video sequence
and also unique and robust identification of visual material. An overview of the visual description tools is
shown in Figure 1.
The basic structure description tools include five supporting tools of visual descriptions defined in
Clauses 6-11. They are categorized into two groups, descriptor containers and basic supporting tools. The
former consists of three datatypes, GridLayout providing efficient representations of visual features on grids,
TimeSeries representing temporal arrays of several descriptions, GofGopFeature describes representative
descriptions over video segment, and MultipleView describing a 3D object using several pictures captured
from different view angles. The latter contains two tools, Spatial2DcoordinateSystem used to specify the 2D
coordinate system and TemporalInterpolation indicating the interpolation method between two samples on a
time axis.
The remaining description tools, except for the FaceRecognition and ImageSignature descriptors, are
associated with visual features and are grouped into five feature categories: Color, Texture, Shape, Motion
and Localization.
The color description tools include five color descriptors to represent different aspects of color features:
representative colors (DominantColor), color distribution (ScalableColor), spatial distribution of colors
(ColorLayout and ColorStructure) and perceptual feeling of illumination color (ColorTemperature). It also
contains three supporting tools, ColorSpace and ColorQuantization used in DominantColor and
IlluminationInvariantColor to extend four color descriptors, DominantColor, ScalableColor, ColorLayout and
ColorStructure, to support illumination invariant similarity matching. An extension of ScalableColor to a group
of frames or pictures (GoFGoPColor) is also included in this group. All the color descriptors can be extracted
from arbitrarily shaped regions.
The texture description tools facilitate browsing (TextureBrowsing) and similarity retrieval
(HomogeneousTexture and EdgeHistogram) using the texture of a still or moving image region. All the texture
descriptors can be extracted from arbitrarily shaped regions.
The shape description tools include two descriptors that characterize different shape features of a 2D object or
region. The RegionShape descriptor captures the distribution of all pixels within a region and the Contour
Shape descriptor characterizes the shape properties of the contour of an object. The extension of
RegionShape is also defined as ShapeVariation to describe temporal variation of shape over video segment.
The Shape3D and Perceptual 3D Shape descriptors provide 3-dimensional shape information; the former
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ISO/IEC 15938-3:2002/Amd.4:2010(E)
represents an intrinsic shape characterization of 3D mesh models, and the latter represents part-based
representation of a 3D object.
The motion description tools include four descriptors that characterize various aspects of motion. The
CameraMotion descriptor specifies a set of basic camera operations such as, for example, panning and tilting.
The motion of a key point (pixel) from a moving object or region can be characterized by the MotionTrajectory
descriptor. The ParametricMotion descriptor characterizes an evolution of an arbitrarily shaped region over
time in terms of a 2D geometric transformation. Finally, the MotionActivity descriptor captures the pace of the
motion in the sequence, as perceived by the viewer. All motion descriptors except for CameraMotion can be
extracted from arbitrarily shaped regions.
The localization description tools can be used to indicate regions of interest in the spatial (RegionLocator) and
spatio-temporal (SpatioTemporalLocator) domains.
The FaceRecognition descriptor and the Advanced Face Recognition descriptor are not associated with any
particular visual feature and can be used to describe a human face for applications requiring the matching and
retrieval of face images.
The signature descriptors provide a "fingerprint" that uniquely identifies image and video content. The
signatures are robust (unchanging) across a wide range of common editing operations, but are sufficiently
different for every item of "original" content to allow unique and reliable identification – just like human
fingerprints. There are two visual signatures; the ImageSignature and VideoSignature are descriptors for
images and videos respectively. The signatures have no direct association with specific visual features such
as colour, shape or texture.
2 © ISO/IEC 2010 – All rights reserved

ISO/IEC 15938-3:2002/Amd.4:2010(E)
Basic Structures
Descriptor Containers Basic Supporting Tools
GridLayout TemporalInterpolation
TimeSeries Spatial2DcoordinateSystem
GofGopFeature
MultipleView
Visual Features
Color
Color Feature Descriptors
Color Supporting Tools
DominantColor ColorSpace
ScalableColor ColorQuantization
ColorLayout IlluminationInvariantColor
ColorStructure
GofGopColor
ColorTemperature
Texture Shape Motion
HomogeneousTexture RegionShape CameraMotion
TextureBrowsing ContourShape MotionTrajectory
EdgeHistogram ParametricMotion
ShapeVariation
MotionActivity
Shape3D
Perceptual 3D Shape
Localization
RegionLocator
SpatioTemporalLocator
Other
Signatures
FaceRecognition
ImageSignature
AdvancedFaceRecognition
VideoSignature
Figure 1 — Overview of Visual Description Tools
In 3.3, extend the definitions:
floor Maximum integer number less than or equal to the given floating point number
Replace 4.2.2 with:
4.2.2 Generic binary representation
The use of the video-specific syntax is signalled using the codec configuration mechanism defined in
ISO/IEC 15938-1. The following classification scheme is defined for this purpose.
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ISO/IEC 15938-3:2002/Amd.4:2010(E)


MPEG7CameraMotion
ISO/IEC 15938-3 Binary Camera Motion
Codec


MPEG7ColorLayout
ISO/IEC 15938-3 Binary Color Layout
Codec


MPEG7ColorQuantization
ISO/IEC 15938-3 Binary Color Quantization
Codec


MPEG7ColorSpace
ISO/IEC 15938-3 Binary Color Space
Codec


MPEG7ColorStructure
ISO/IEC 15938-3 Binary Color Structure
Codec


MPEG7ContourShape
ISO/IEC 15938-3 Binary Contour Shape
Codec


MPEG7DominantColor
ISO/IEC 15938-3 Binary Dominant Color
Codec


MPEG7EdgeHistogram
ISO/IEC 15938-3 Binary Edge Histogram
Codec


MPEG7FaceRecognition
ISO/IEC 15938-3 Binary Face Recognition
Codec


MPEG7FoFGoPColor
ISO/IEC 15938-3 Binary GoFGoP Color
Codec


MPEG7GridLayout
ISO/IEC 15938-3 Binary Grid Layout
Codec


MPEG7HomogeneousTexture
ISO/IEC 15938-3 Binary Homogeneous Texture
Codec
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ISO/IEC 15938-3:2002/Amd.4:2010(E)


MPEG7IrregularVisualTimeSeries
ISO/IEC 15938-3 Binary Irregular Time Series
Codec


MPEG7MotionActivity
ISO/IEC 15938-3 Binary Motion Activity
Codec


MPEG7MotionTrajectory
ISO/IEC 15938-3 Binary Motion Trajectory
Codec


MPEG7MultipleView
ISO/IEC 15938-3 Binary Multiple View
Codec


MPEG7ParametricMotion
ISO/IEC 15938-3 Binary Parametric Motion
Codec


MPEG7RegionLocator
ISO/IEC 15938-3 Binary Region Locator
Codec


MPEG7RegionShape
ISO/IEC 15938-3 Binary Region Shape
Codec


MPEG7RegularVisualTimeSeries
ISO/IEC 15938-3 Binary Regular Time Series
Codec


MPEG7ScalableColor
ISO/IEC 15938-3 Binary Scalable Color
Codec


MPEG7Shape3D
ISO/IEC 15938-3 Binary Shape 3D
Codec


MPEG7Spatial2DCoordinateSystem
ISO/IEC 15938-3 Binary Spatial 2D Coordinate
System Codec


MPEG7SpatioTemporalLocator
ISO/IEC 15938-3 Binary SpatioTemporal Locator
Codec
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ISO/IEC 15938-3:2002/Amd.4:2010(E)


MPEG7TemporalInterpolation
ISO/IEC 15938-3 Binary Temporal Interpolation
Codec


MPEG7TextureBrowsing
ISO/IEC 15938-3 Binary Texture Browsing
Codec


MPEG7GofGopFeature
ISO/IEC 15938-3 Binary Gof Gop Feature
Codec


MPEG7ColorTemperature
ISO/IEC 15938-3 Binary Color Temperature
Codec


MPEG7ShapeVariation
ISO/IEC 15938-3 Binary Shape Variation
Codec


MPEG7IlluminationInvariantColor
ISO/IEC 15938-3 Binary Illumination Invariant
Color Codec


MPEG7AdvancedFaceRecognition
ISO/IEC 15938-3 Binary Advanced Face Recognition
Codec


MPEG7Perceptual3DShape
ISO/IEC 15938-3 Binary Perceptual 3D Shape
Codec


MPEG7ImageSignature
ISO/IEC 15938-3 Binary Image Signature
Codec


MPEG7VideoSignature
ISO/IEC 15938-3 Binary Video Signature
Codec


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ISO/IEC 15938-3:2002/Amd.4:2010(E)
In 5.2.4, replace Table 1 with:
Table 1 — Assignment of IDs to descriptors
ID Descriptor
0 Forbidden
1 CameraMotion
2 ColorLayout
3 ColorSpace
4 ColorStructure
5 ColorQuantization
6 ContourShape
7 DominantColor
8 EdgeHistogram
9 FaceRecognition
10 GoFGoPColor
11 GridLayout
12 HomogeneousTexture
13 IrregularVisualTimeSeries
14 MotionActivity
15 MotionTrajectory
16 MultipleView
17 ParametricMotion
18 RegionLocator
19 RegionShape
20 RegularVisualTimeSeries
21 ScalableColor
22 Shape3D
23 Spatial2DCoordinateSystem
24 SpatioTemporalLocator
25 TemporalInterpolation
26 TextureBrowsing
27 GofGopFeature
28 ColorTemperature
29 ShapeVariation
30 IlluminationInvariantColor
31 AdvancedFaceRecognition
32 Perceptual3DShape
33 ImageSignature
34 VideoSignature
35-255 Reserved
After 11.3, add the following:
11.4 Video Signature
11.4.1 Introduction
The visual content descriptors in Sections 6-9 are very useful when trying to find videos with similar content.
These descriptors are intended to be general and were found to be unsuitable for the task of finding duplicate
content. The video signature descriptor is designed to identify duplicate video content. This descriptor is
robust (unchanging) to a wide range of common video editing operations, but is sufficiently different for every
"original" content to identify it uniquely and reliably – just like human fingerprints.
© ISO/IEC 2010 – All rights reserved 7

ISO/IEC 15938-3:2002/Amd.4:2010(E)
The video signature is composed of three main elements,
• a frame signature,
• a set of compact summary frame signatures - referred to as words
• and a group-of-frames representation for a temporal segment -referred to as a bag-of-words.
A video is assumed to be made up of a set of frames (or pictures) each representing a single temporal sample.
A frame is made of a set of pixels each representing a single spatial sample. The frame signature is extracted
from each frame of a video. It is a 380 dimensional vector of base-3 ternary values that describe the
intensities and the intensity inter-relations between pixel regions in the frames. Each dimension can be
characterized as a mean, first or second order operator.
Words are compact, 1 byte, representations of the frame signature. All possible combinations of values for a
word are referred to as the vocabulary. The words provide a summary representation of the frame.
A bag-of-words representation is often used in text searching to compare the similarity between two
documents. It ignores the ordering of the text and therefore provides some robustness to editing. For the video
signature a bag-of-words records the occurrence of words within a temporal segment of frames. The bag-of-
words therefore provides a coarse descriptor for the temporal segment.
The video signature descriptor syntax provides support for description of single or multiple static spatial
regions within the frame. Each spatial region is a rectangular region having arbitrary position and size, with
edges parallel to the edges of the frame. Each spatial region may have its own start and end media times.
This feature is useful when describing content such as videos with picture-in-picture, where the entire frame
region can be described as the first spatial region and the picture-in-picture region can be described as the
second spatial region.
The extraction procedure shall be applied to each spatial region independently. Specifically, only pixels within
the spatial region are processed to extract the video signature.
11.4.2 DDL representation syntax

























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ISO/IEC 15938-3:2002/Amd.4:2010(E)




























































© ISO/IEC 2010 – All rights reserved 9

ISO/IEC 15938-3:2002/Amd.4:2010(E)






Descriptor example:



0 0
719 479

0
1000

0
5038


0
89

0
2969

1 1 1 1 0 1 0 0 .
.............

.............



0
100
1 2 3 4 5
1 2 1 0 1 0 2 1 0 2 .
.............





10 © ISO/IEC 2010 – All rights reserved

ISO/IEC 15938-3:2002/Amd.4:2010(E)
11.4.3 Binary Representation Syntax
VideoSignature { Number of bits Mnemonics
NumOfSpatialRegions 32 uimsbf
for( r=0; r< NumOfSpatialRegions; r++ ) {
SpatialLocationFlag 1 bslbf
if( SpatialLocationFlag == 1 ) {
for(i=0;i<2;i++){
PixelX 16 uimsbf
PixelY 16 uimsbf
}
}
StartFrameOfSpatialRegion 32 uimsbf
NumOfFrames 32 uimsbf
MediaTimeUnit 16 uimsbf
MediaTimeFlagOfSpatialRegion 1 bslbf
if( MediaTimeFlagOfSpatialRegion == 1 ) {
StartMediaTimeOfSpatialRegion 32 uimsbf
EndMediaTimeOfSpatialRegion 32 uimsbf
}
NumOfSegments 32 uimsbf
for( i=0; i< NumOfSegments; i++ ) {
StartFrameOfSegment 32 uimsbf
EndFrameOfSegment 32 uimsbf
MediaTimeFlagOfSegment 1 bslbf
if( MediaTimeFlagOfSegment == 1 ) {
StartMediaTimeOfSegment 32 uimsbf
EndMediaTimeOfSegment 32 uimsbf
}
for( j=0; j< WordsPerFrame; j++ ) {
BagOfWords[j] 243 bslbf
}
}
CompressionFlag 1 bslbf
if(CompressionFlag ==0) {
for( i=0; i< NumOfFrames; i++ ) {
MediaTimeFlagOfFrame 1 bslbf
if( MediaTimeFlagOfFrame == 1 ) {
MediaTimeOfFrame 32 uimsbf
}
FrameConfidence 8 uimsbf
for( j=0; j< WordsPerFrame; j++ ) {
Word[j] 8 uimsbf
}
FrameSignature 608 bslbf
}
} else {
for (i=0; i MediaTimeFlagOfFrame 1 bslbf
if( MediaTimeFlagOfFrame == 1 ) {
MediaTimeOfFrame 32 uimsbf
}
FrameConfidence 8 uimsbf
for (j=0; j < WordsPerFrame; j++) {
Word[j] 8 uimsbf
}
}
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ISO/IEC 15938-3:2002/Amd.4:2010(E)
CompressedSegmentLength = 45
n = 0
for (i=0; i < NumOfSegments; i++) {
if (i == NumOfSegments -1 ) {
CompressedSegmentLength = NumOfFrames -
n
}
CompressedSegment( ) bslbf
n += CompressedSegmentLength
}
}
}
}
Number of bits Mnemonics
CompressedSegment {
num_frames = 0
while (num_frames < CompressedSegmentLength) {
FrameSignature 608 bslbf
GOPLengthm1 ceil(ld(Segment uimsbf
Length))
PredictedPictures( ) bslbf
num_frames = num_frames + GOPLengthm1 + 1
}
}
PredictedPictures { Number of bits Mnemonics
decoded_el = 0
num_el = GOPLengthm1 × 380
while (decoded_el < num_el) {
ZeroRL Variable (see Exp- bslbf
Golomb coding in
11.4.9.1).
decoded_el = decoded_el + ZeroRL
if (decoded_el == num_el) then break
NonZeroSymbol 1
decoded_el = decoded_el + 1
}
}
WordsPerFrame = 5
11.4.4 Descriptor Component Semantics
NumOfSpatialRegions
This field, which is only present in the binary syntax, specifies the number of spatial regions from the video.
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ISO/IEC 15938-3:2002/Amd.4:2010(E)
SpatialLocationFlag
This field, which is only present in the binary syntax, indicates the presence of the PixelX, PixelY, elements,
which specify the location of the spatial region. If the flag is set to 1 these elements are present, if the flag is
set to 0 these elements are not present.
VideoSignatureSpatialRegion, Pixel, PixelX, PixelY
These attributes specify a rectangular region, by locating the position of the top-left and bottom-right points.
The origin of the coordinate system (0,0) is in the top-left corner of the frame. In the binary representation the
position of the top-left corner of the region is specified by the first occurrence of (PixelX, PixelY) and the
position of the bottom-right corner is specified by the second occurrence of (PixelX, PixelY). Where, PixelX
and PixelY specify respectively the X and Y coordinates of a pixel. In the DDL representation the position of
the top-left corner of the region is specified by the first occurrence of Pixel, and the position of the bottom-right
corner is specified by the second occurrence of Pixel. Where the first element of the Pixel vector corresponds
to the X coordinate and the second element corresponds to the Y coordinate.
StartFrameOfSpatialRegion
This element specifies the frame index of the first frame represented in the spatial region representation.
NumOfFrames
This field, which is only present in the binary representation, specifies the number of frame signatures
represented in the spatial region representation.
MediaTimeUnit
This element specifies the unit of the media time as a fraction of a second. For example, if MediaTimeUnit is
1000, the unit of the media time is 1/1000 second. The time unit specified by this element is used as a time
unit for the elements StartMediaTimeOfSpatialRegion, EndMediaTimeOfSpatialRegion,
StartMediaTimeOfSegement, EndMediaTimeOfSegment, and MediaTimeOfFrame.
MediaTimeFlagOfSpatialRegion
This field, which is only present in the binary representation, indicates the presence of the fields specifying the
start and end media time of the spatial region representation, i.e. the elements
StartMediaTimeOfSpatialRegion and EndMediaTimeOfSpatialRegion. If the flag is set to 1 the elements are
present if the flag is set to 0 the elements are not present.
MediaTimeOfSpatialRegion, StartMediaTimeOfSpatialRegion, EndMediaTimeOfSpatialRegion
These elements specify the media time of the first (StartMediaTimeOfSpatialRegion) and last
(EndMediaTimeOfSpatialRegion) frame represented in the spatial region.
NumOfSegments
This field, which is only present in the binary representation, specifies the number of temporal segments
represented, these are referred to as bag-of-words.
StartFrameOfSegment, EndFrameOfSegment
These elements specify the frame index of the first (StartFrameOfSegment) and last (EndFrameOfSegment)
frames represented in the temporal segment.
MediaTimeFlagOfSegment
This field, which is only present in the binary representation, indicates the presence of the fields specifying the
start and end media time of the segment, i.e. the elements StartMediaTimeOfSegment and
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ISO/IEC 15938-3:2002/Amd.4:2010(E)
EndMediaTimeOfSegment. If the flag is set to 1 the elements are present, if the flag is set to 0 the elements
are not present.
MediaTimeOfSegment, StartMediaTimeOfSegment, EndMediaTimeOfSegment
These elements specify the media time of the first (StartMediaTimeOfSegment) and last
(EndMediaTimeOfSegment) frame represented in the temporal segment.
WordsPerFrame
This element specifies the number of Word elements extracted from each frame.
VSVideoSegment
This element specifies a representation of a temporal segment in a video.
BagOfWords
This element specifies the bag-of-words representation for a temporal segment of 90 frames, for all but the
last segments. The extraction of bag-of-words is described in 11.4.8.
MediaTimeFlagOfFrame
This field, which is only present in the binary representation, indicates the presence of the element
MediaTimeOfFrame. If the flag is set to 1, the element is present, if the flag is set to 0 the element is not
present.
MediaTimeOfFrame
This element specifies the media time of the frame.
VideoFrame
This element specifies a representation of a single video frame.
FrameConfidence
This element specifies the confidence value attributed to a frame signature. Low frame confidence represents
a flat image where there is little or no luminance difference between sub-regions, for example a black screen.
The extraction of confidence is described in 11.4.6.
Word
This element specifies a compact representation of the frame signature. The extraction of Word elements is
described in 11.4.7.
FrameSignature
This element specifies the full video signature representation of the frame. It is a 380 dimensional vector of
base-3 ternary values {}0,1,2 . The extraction of frame signature is described in 11.4.5.
In the binary representation the extracted ternary elements x = {x ,x ,�,x } shall be encoded in
1 2 380
5-dimensional units, where each unit is encoded into 8 bits. Therefore, a total of 380/5=76 units (608 bits) are
used to encode the frame signature.
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ISO/IEC 15938-3:2002/Amd.4:2010(E)
Let b , j = 1,…,76 denote the encoded value of each 5-dimensional unit which shall be calculated using
j
the following equation:
b = 81×x + 27 ×x + 9×x + 3×x + x ,
j 5j−4 5j−3 5j−2 5j−1 5j
the encoding is shown explicitly in Table E.1.
In the CompressedSegment field the FrameSignature element is a key picture.
CompressionFlag
This field, only present in the binary syntax, indicates whether the frame signatures are compressed. When
CompressionFlag is set to 1 the corresponding frame signatures are compressed, when the field is set to 0
the frame signatures are not compressed.
CompressedSegment
This field, only present in the binary syntax, specifies the frame signatures in a compressed form. The
ordering of compressed segments corresponds to the ordering of the temporal segments (bag-of-words) and
the start frame of each compressed segment corresponds to the StartFrameOfSegment element. The
decoding of the compressed segment is specified in 11.4.9.
CompressedSegmentLength
This field, only present in the binary syntax, specifies the length of a compressed segment, in number of
frames. It shall be equal to 45 for all but the last segment. In the last segment it shall be NumOfFrames - 45 *
(NumOfSegments - 1).
GOPLengthm1
This field, only present in the binary syntax, specifies the GOP length, in number of frames minus one. For
instance, GOP consisting of one KP and one PP has the value of this field equal to 1.
PredictedPictures
This field, only present in the binary syntax, specifies part of the bit-stream with encoded predicted pictures.
The decoding of the PredictedPictures field is specified in 11.4.9.1.
ZeroRL
This field, only present in the binary syntax, specifies the length of run of ternary 0 encoded using the Exp-
Golomb coding.
NonZeroSymbol
This field, only present in the binary syntax, specifies an encoded symbol. When this field is equal to 0 the
symbol is ternary 1. When this field is equal to 1 the symbol is ternary 2.
11.4.5 Frame Signature Extraction
This Subclause specifies the extraction process for the FrameSignature element of the Video Signature
descriptor.
© ISO/IEC 2010 – All rights reserved 15

ISO/IEC 15938-3:2002/Amd.4:2010(E)
0123456789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127
128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159
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224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255
256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287
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480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511
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544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575
576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607
608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639
640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671
672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703
704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735
736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767
768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799
800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831
832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863
864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895
896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927
928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959
960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991
992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023
Figure Amd4-1 — Block partitioning and indices.
The extraction of frame signature shall be carried out for each spatial region independently. Specifically, only
pixels within the spatial region shall be processed to extract the frame signature, as if the spatial region
formed the entire frame region. Hereafter, the term “frame” refers to the entire frame region or a spatial region
thereof.
The 380 dimensional ternary vector is extracted from predefined sub-regions associated with each dimension.
The luminance values of a frame shall be spatially resampled to 32x32 pixel resolution, where the width and
the height of the frame are equally split into 32. Figure Amd4-1 shows the block partitioning and the indices
given to each resampled pixel. These resampled pixels are used to construct the sub-regions. Here,
luminance shall be the Y component of the YCbCr colour space defined in 6.2 Color Space.
Tables F.1 and F.2 show the indices of the pixels which construct the sub-regions associated with each
dimension. Dimensions 1-32 (Table F.2), which are called the average element dimensions, have one
associated sub-region. Dimensions 33-380 (Table F.2), which are called the difference element dimensions,
have two associated sub-regions. The notation “m-n” in Tables F.1 and F.2 represents a rectangular region
with the index of its top-left pixel being m, and the index of its bottom-right pixel being n. Symbol “|” represents
that the sub-region is composed of multiple rectangular regions separated by this symbol. For example “m-n |
o-p | q-r” represents a region that is composed of three rectangular regions of “m-n”, “o-p”, and “q-r”.
Dimensions 1-32 (average element dimensions) are further categorized by their patterns of sub-regions into
2 different pattern-types (pattern-type A1 and A2), specified in the second column of Table F.1. Dimensions
33-380 (difference element dimensions) are further categorized by their patterns of sub-regions into 8 different
pattern-types (pattern-type D1 – D8), specified in the second column of Table F.2. Figures G.1 to G.8 show
samples of sub-regions for dimensions 21, 33, 149, 174, 210, 240, 302, and 311, respectively.
Ternary values of dimensions 1-32 (average element dimensions) shall be calculated by quantizing the
average luminance of the associated sub-region. Ternary values of dimensions 33-380 (difference element
dimensions) shall be calculated by quantizing the differences between the average luminances of the
associated two sub-regions. Thus, the frame signature is composed of a ternary value vector with 32 average
element dimensions, and 348 difference element dimensions.
16 © ISO/IEC 2010 – All rights reserved

ISO/IEC 15938-3:2002/Amd.4:2010(E)
The extraction of the frame signature from a video frame is carried out in 3 steps.
Step 1
The frame luminance shall be spatially resampled to 32x32 pixel resolution. The luminance corresponds to the
Y component of the YCbCr colour space, ranged [0,255]. The spatial resampling shall be done by partitioning
the frame into 32x32 blocks, where the width and the height of the frame shall both be split into 32 equal
regions, as shown in Figure Amd4-1. Then, the mean luminance shall be calculated for each block. The mean
luminance shall be calcu
...