Moving Pictures Experts Group

Description

Within the 3GPP ecosystem, the Moving Pictures Experts Group (MPEG) refers not to the group itself but to the suite of multimedia coding standards developed by it (ISO/IEC JTC 1/SC 29/WG 11) that are adopted and profiled for use in mobile telecommunications. 3GPP does not develop its own codecs but instead incorporates and specifies the use of MPEG standards across numerous technical specifications (TSs). Key MPEG standards referenced include MPEG-4 for video and audio coding (Part 2 Visual, Part 3 Audio, and most importantly Part 10 Advanced Video Coding - AVC/H.264 and later Part 10 High Efficiency Video Coding - HEVC/H.265), MPEG-2 Transport Stream for broadcasting, and MPEG-4 file format (ISO Base Media File Format) for storage and streaming.

The integration works by 3GPP defining specific profiles and levels of these MPEG standards that are mandatory or recommended for interoperability. For instance, 3GPP mandates the H.264/AVC codec for basic video telephony and streaming services. The specifications detail how these codecs are used in different services: in Packet-Switched Streaming Service (PSS - TS 26.234), the 3GPP file format (a derivative of the MP4 format) is used; in Multimedia Broadcast/Multicast Service (MBMS - TS 26.346), MPEG-2 TS is specified for delivery; and for IMS Multimedia Telephony (MMTel), specific RTP payload formats for MPEG-4 audio (AAC) and video are defined. The architecture involves the codec residing in the UE's media processing engine and in media gateways or application servers in the network.

Key components referenced across dozens of 3GPP specs include the decoder configuration information, synchronization layers, and delivery protocols. The role of MPEG standards in 3GPP is foundational: they provide the efficient compression necessary to deliver acceptable quality video and audio over bandwidth-constrained and variable-bitrate radio channels. They enable a wide range of services from simple ringback tones to high-definition video conferencing and mobile TV. The specifications ensure that any compliant UE can decode the media streams sent by a compliant server, guaranteeing global interoperability for multimedia services.

Purpose & Motivation

The referencing of MPEG standards within 3GPP, starting from the earliest releases (R99), was motivated by the fundamental need to add multimedia capabilities to digital cellular networks beyond voice. Prior to 3G, mobile networks were primarily circuit-switched voice systems. The advent of packet-switched data in 2.5G and 3G created an opportunity for video and audio services, but these required highly efficient compression to be feasible over limited and expensive data connections. Developing entirely new, proprietary codecs would have been inefficient and fragmented the market.

3GPP's purpose in adopting MPEG standards was to leverage existing, robust, and internationally recognized compression technology. MPEG-4, in particular, offered a comprehensive suite of tools for audio-visual coding, scene description, and file formatting that was ideal for the heterogeneous delivery environments of mobile networks (streaming, download, broadcast). This solved the problem of interoperability and accelerated the deployment of multimedia services. By profiling MPEG standards, 3GPP ensured that devices and networks had a common, optimized language for media, which was crucial for the success of services like video calling, mobile TV (MBMS), and later, high-quality streaming over LTE and 5G. It represents a key example of 3GPP's strategy of integrating best-of-breed external standards to build a complete system.

Key Features

• Adoption of MPEG-4 AVC/H.264 and HEVC/H.265 as mandatory video codecs for various services
• Specification of the 3GPP file format based on ISO Base Media File Format (MP4)
• Use of MPEG-2 Transport Stream for broadcast/multicast delivery in MBMS
• Profiling of Advanced Audio Coding (AAC) family codecs for high-efficiency audio
• Definition of RTP payload formats and session description parameters for MPEG media
• Support for adaptive streaming techniques (e.g., DASH) built upon MPEG media segments

Evolution Across Releases

Defining Specifications