IEC TR 63669:2026

• Abstract:

  IEC TR 63669:2026 describes multimedia services that combine heterogeneous media data and proposes the concept of alignment of heterogeneous media streams to address the common challenges these services face. Based on the conceptual model and the analysis of relevant technologies and standards, this document also proposes items for future standardization.

• Status: Published
• Publication Date: 27-May-2026
• ICS: 33.160.60 - Multimedia systems and teleconferencing equipment
• Technical Committee: TA 18 - Multimedia home systems and applications for end-user networks
• Drafting Committee: MT 62680-1-2 - TC 100/TA 18/MT 62680-1-2
• Current Stage: PPUB - Publication issued
• Start Date: 28-May-2026
• Completion Date: 19-Jun-2026

IEC TR 63669:2026 is a Technical Report from the International Electrotechnical Commission (IEC) about alignment of heterogeneous media data streams. It describes multimedia services that combine data such as video, audio, sensor signals, haptic data, 3D audio and geospatial information, and it proposes ideas for future standardization. The document is aimed at people designing, integrating or standardizing these kinds of multimedia systems.

What does IEC TR 63669:2026 specify?

IEC TR 63669:2026 specifies a conceptual view of multimedia services that combine heterogeneous media data and explains the idea of aligning those data streams. It also organizes the discussion around service examples, a three-layer alignment model, and future standardization topics.

The report is organized into an overview and case studies:

• Clause 1 sets the scope.
• Clause 2 covers normative references.
• Clause 3 lists abbreviations used in the document.
• Clause 4 explains the purpose, media combinations, media classification, the alignment concept, and candidate standardization items.
• Clause 5 gives case studies for virtual worlds, interactive 3D multimedia content, and remote collaboration systems.
• The bibliography lists related publications and examples.

Clause	Main topic
4	Conceptual model, media combinations, alignment layers, and standardization candidates
5	Case studies for photorealistic virtual worlds, virtual music events, and remote collaboration

What are the key requirements of IEC TR 63669:2026?

IEC TR 63669:2026 is a Technical Report, so Clause 4 and Clause 5 describe a framework and proposed standardization topics rather than mandatory conformance rules. The most important points are the service model, the three-layer alignment concept, and the gaps the report identifies for future work.

Purpose and problem statement

Clause 4.1 says the purpose is to establish a standardized framework for combining heterogeneous media data into multimedia data. In practice, the report is trying to reduce interoperability problems, poor reuse, scalability issues and data silos that appear when each service invents its own integration method.

Media combinations the report focuses on

Clause 4.2 highlights three recurring service patterns:

• Photorealistic virtual world
• Interactive 3D multimedia content
• Remote collaboration system

These examples matter because they show why one common model is needed. Some services need replay or querying by location as well as time, while others need spatial placement of video and audio or real-time synchronization of video, audio and sensor data.

Classification of media data

Clause 4.3 groups the media types used in these services, including video, image, audio, text, animation, 3D model, point clouds, haptic data, motion and orientation data, and geospatial data. The table also shows representative formats where they are already used. For a project team, this helps define which media types must be handled together and which ones still lack widely adopted standard formats.

Three-layer alignment model

Clause 4.4 presents the alignment concept as three layers:

• Input layer - receives heterogeneous media streams from devices and keeps ordering information such as timestamps or sequence numbers.
• Process layer - aligns incoming streams, attaches metadata, and groups the data according to relationships between streams.
• Output layer - delivers the aligned multimedia data and can convert it into different stream formats.

This is the core technical idea of the report. It matters because service builders need to decide where alignment happens, what metadata has to travel with the data, and how the result will be delivered to applications and end users.

Standardization topics the report proposes

Clause 4.5 identifies candidate items for future standardization:

• Data format for the input layer
• Protocol for the input layer
• Alignment method for the process layer
• Schema definition and representation for the process layer
• Data format for the output layer
• Protocol for the output layer
• Delay evaluation method for the output layer

In practice, these are the decision points that affect whether different devices and services can work together, whether the aligned data can be queried by time or space, and whether real-time services can tolerate the delay introduced by processing.

Gaps and focus items

Clause 4.5.2 and 4.5.3 point to three main gaps for future standardization:

• Standardized methods to align streams such as 360° video, 3D audio, sensor signals and haptic data
• A shared schema or metadata representation for relationships among streams
• Data formats that support reordering and conversion between reference axes such as time and space

For implementers, this means the report is not prescribing a finished solution. It is identifying where standards work is still needed.

What terms does IEC TR 63669:2026 define?

IEC TR 63669:2026 uses these abbreviations and working terms in its discussion:

• DDL - Data definition language, used for describing schemas and structures.
• MPEG - Moving Picture Experts Group, the standards family and organization name used in media-related references.
• MPEG-DASH - MPEG Dynamic adaptive streaming over HTTP, a streaming method named in the report.
• MP4 - MPEG-4 Part 14 file format, cited as a container format for output data.
• RTP - Real-time transport protocol, used for media transport.
• RTCP - Real-time control protocol, used with RTP for control and feedback.
• SDO - Standard Development Organization, the generic term for standards bodies.
• VR - Virtual reality, used in the case studies and use-case descriptions.

Who uses IEC TR 63669:2026?

IEC TR 63669:2026 is useful to engineers and architects working on multimedia systems that combine several media types. That includes teams building virtual reality services, telepresence systems, immersive live experiences, and other interactive media services.

It is also relevant to:

• Standards developers working on media transport, metadata, alignment and immersive media
• Product teams integrating video, audio, sensor and haptic data
• Platform developers working on streaming, container formats and queryable media data
• Quality and interoperability teams evaluating whether different components can share aligned data
• Buyers and system owners comparing solutions for remote collaboration, immersive media, or sensor-rich multimedia services

What changed in IEC TR 63669:2026 from the previous edition?

IEC TR 63669:2026 is the first edition identified in the publication data.

What does the IEC TR 63669:2026 document contain?

IEC TR 63669:2026 contains an overview of the alignment problem, a media-type classification table, a three-layer alignment model, and an analysis of existing and emerging standards related to the topic. It also includes figures that illustrate abstraction, media combination, sequential alignment, the alignment process, and flexible alignment across different reference axes.

Table 2 lists the candidate standardization items by layer. Tables 3 and 4 map those items to existing standards and to emerging standards, which helps readers see where current technology already covers the need and where gaps remain.

The case study clause is practical rather than normative. It shows how the alignment concept applies to a photorealistic virtual world, a virtual music event, and a remote collaboration system, including examples such as virtual city exploration, virtual tours, remote guided tours, remote work guidance, and VR meetings.

The bibliography points to the media, transport, time-synchronization, wearable, haptics, and immersive-media references discussed in the body of the report.

IEC TR 63669 ®
Edition 1.0 2026-05
TECHNICAL
REPORT
Alignment of heterogeneous media data streams

ICS 33.160.60  ISBN 978-2-8327-1250-4

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CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, and abbreviated terms . 6
3.1 Terms and definitions. 6
3.2 Abbreviated terms . 6
4 Overview . 6
4.1 Purpose . 6
4.2 Combination of media data . 7
4.2.1 General . 7
4.2.2 Photorealistic virtual world . 8
4.2.3 Interactive 3D multimedia content . 8
4.2.4 Remote collaboration system . 9
4.3 Classification of media data . 9
4.4 Concept of alignment of heterogeneous media data streams. 10
4.4.1 General . 10
4.4.2 Input layer . 11
4.4.3 Process layer. 11
4.4.4 Output layer . 12
4.5 Items of standardization . 12
4.5.1 Potential items of standardization . 12
4.5.2 Standards gap analysis of related technologies . 13
4.5.3 Focus items for standardization . 15
5 Case study . 15
5.1 Photorealistic virtual world . 15
5.1.1 Virtual city exploration . 15
5.1.2 Virtual tour . 15
5.2 Interactive 3D multimedia content - Virtual music events experience . 16
5.3 Remote collaboration system . 16
5.3.1 Remote guided tours . 16
5.3.2 Remote work guidance . 16
5.3.3 VR meeting . 16
Bibliography . 17

Figure 1 – Abstraction of services by heterogeneous media data . 7
Figure 2 – Combination of media data. 7
Figure 3 – Example of MovieMap . 8
Figure 4 – Example of T-Leap . 9
Figure 5 – Sequential alignment of video and audio streams in multimedia . 10
Figure 6 – Concept of alignment of heterogeneous media data streams . 11
Figure 7 – Alignment process . 12
Figure 8 – Flexible alignment of multimedia streams . 12

Table 1 – Media types . 9
Table 2 – Potential items of standardization . 13
Table 3 – Mapping of potential standardization items to existing standards . 13
Table 4 – Mapping of potential standardization items to emerging standards . 14

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Alignment of heterogeneous media data streams

FOREWORD
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IEC TR 63669 has been prepared by IEC technical committee 100: Audio, video and multimedia
systems and equipment. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
100/4460/DTR 100/4491/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.
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INTRODUCTION
Driven by advances in digital technologies, new multimedia services have emerged. These
services combine advanced media types-such as sensor signals and haptic data – alongside
enhanced versions of video and audio-such as 360° video and 3D audio. While standards exist
for combining conventional media data (e.g. video, audio) into "multimedia data", currently there
is no standard covering these emerging media data. Consequently, each service independently
implements its own approach for combining these media data. This leads to problems such as
limited interoperability, reduced reusability, scalability concerns, and data silos. This document
clarifies multimedia services that combine emerging heterogeneous media data and the concept
of alignment of heterogeneous media streams to address the common challenges these
services face. Based on the conceptual model and the analysis of relevant technologies and
standards, this document also proposes items for future standardization.
1 Scope
This document describes multimedia services that combine heterogeneous media data and
proposes the concept of alignment of heterogeneous media streams to address the common
challenges these services face. Based on the conceptual model and the analysis of relevant
technologies and standards, this document also proposes items for future standardization.
2 Normative references
There are no normative references in this document.
3 Terms, definitions, and abbreviated terms
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.2 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply:
DDL Data definition language
MPEG Moving Picture Experts Group
MPEG-DASH MPEG Dynamic adaptive streaming over HTTP
MP4 MPEG-4 Part 14 file format
RTCP Real-time control protocol
RTP Real-time transport protocol
SDO Standard Development Organization
SQL Structured Query Language
VR Virtual reality
4 Overview
4.1 Purpose
Driven by advances in digital technologies, new multimedia services have rapidly emerged.
These services combine advanced media types-such as sensor signals and haptic data-
alongside enhanced versions of video and audio-such as 360° video and 3D audio. While
standards exist for combining conventional media data (e.g. video, audio) into "multimedia
data", currently there is no standard covering these emerging media data. This leads to issues
such as limited interoperability, reduced reusability, scalability concerns, and data silos.
The purpose of standardization is to establish a standardized framework that can combine
heterogeneous media data into multimedia data and facilitate the development and widespread
adoption of new multimedia products and services.
See Figure 1 for a diagram of abstraction of services by heterogeneous media data.
Figure 1 – Abstraction of services by heterogeneous media data
4.2 Combination of media data
4.2.1 General
This Subclause 4.2 summarizes examples of combinations of media data and their key
characteristics based on the results of an investigation into services that combine
heterogeneous media data:
– Photorealistic virtual world
– Interactive 3D multimedia experiences
– Remote collaboration system
See Figure 2 for an example of combination of media data. Specific service examples are
introduced in Clause 5.
Figure 2 – Combination of media data

4.2.2 Photorealistic virtual world
As shown in the example given in Figure 3, each video frame in a 360° video of a real-world
scene is associated with geospatial information from the time of recording through calculations
or manual processes. Based on this integrated video-frame-geospatial data set, a realistic
virtual world can be created that provides an interactive experience for the user. Conventional
methods of building virtual spaces with 3D-CG modelling software are extremely costly. For this
reason, there is growing demand for computational approaches that generate realistic virtual
worlds from video or images. However, there is currently no standard framework to integrate
geospatial information with videos. This has led to increased costs in the integration process,
and interoperability across different systems remains limited.
A key characteristic of this combination of media data (integrated video-frame-geospatial data
set) is that time is not the only reference for rendering or for replay. For instance, instead of
searching by time, users can render or replay the scene by location or other axes. Therefore,
combined media data must support flexible re-indexing and querying by different references
(e.g. time, space), which can require rearranging the data sequence according to the user's
chosen axis.
Figure 3 – Example of MovieMap
4.2.3 Interactive 3D multimedia content
In this example, an event such as a music concert is recorded using multiple 360° cameras and
microphones. These multiple sets of multimedia data are combined to form a virtual space that
offers users an interactive, highly immersive experience. Conventional video-and-audio-based
experiences tend to be passive and provide limited immersion and presence. Consequently,
there is an increasing need for more interactive, more immersive multimedia experiences.
However, there is no standardized framework for aligning multiple recorded data sets in both
time and space. As a result, generating these data sets can be costly. Moreover, they are often
tied to a specific application, which limits reusability.
A key characteristic of this combination is that multiple video and audio data sets are integrated
spatially for rendering. For instance, each set is placed in three-dimensional space exactly as
it was when originally captured.

4.2.4 Remote collaboration system
In this example, multiple media data streams (e.g. video, audio, and sensor data about a
device's orientation or motion) are transmitted and rendered in real time to provide a highly
immersive collaborative experience for remote collaborators. Conventional voice or video chat
alone has limitations, making it increasingly important to develop systems that allow real-time,
comprehensive understanding of remote conditions and seamless interaction with remote
collaborators. In many cases, existing systems transmit multiple multimedia data streams
separately and integrate and render them in the application. As a result, data consistency and
reusability remain challenges. See Figure 4 for an example of T-leap.
A key characteristic of this combination (of multiple media data streams, such as video, audio,
and sensor data related to a device’s orientation or motion) is that heterogeneous media data
are synchronized and integrated in real time, and dynamic data rendering is provided according
to the user's position and viewpoint.

Figure 4 – Example of T-Leap
4.3 Classification of media data
Table 1 summarizes the classification of key media data types used in services with
heterogeneous media data, along with their representative formats.
Table 1 – Media types
Media type Representative formats
Video H.264|AVC, H.265|HEVC
Image JPEG, PNG
Audio MP3, AAC, Opus
Text ASCII, Unicode ®
Animation
BVH, FBX ®
3D model
glTF™, OBJ, FBX
Point clouds LAS, E57, PCD, PCC
Haptic data No widely adopted standard is currently established.
Motion and orientation data (e.g. No widely adopted standard is currently established.
accelerometer, gyro)
Geospatial data (location, orientation) No widely adopted standard is currently established.
International standards exist for media types that make up conventional multimedia data, such
as video and audio. However, in recent years, advances and diversification in sensor and
display technologies have led to emerging media data — such as sensor-signal data (e.g.
...