The impact of MPEG standards

The impact of MPEG standards

I suppose that few visitors of this blog need to be convinced that MPEG is important because they have some personal experience of the MPEG importance. Again, I suppose not all visitors have full visibility of all the application areas where MPEG is important.

This article describes different application domains showing how applications have benefited from MPEG standards. The list is not exhaustive and the order in which applications are presented follows approximately the time in which MPEG enabled the application.

Digital Television for distribution

MPEG-2 was the first integrated digital television standard first deployed in 1994, even before the MPEG-2 standard was approved. While most countries have adopted MPEG-2 Video for their terrestrial broadcasting services, with one notable major exception, countries have made different selections of for the audio component.

MPEG-2 Transport Stream is the Systems layer of Digital Television. The Systems layer can carry the “format identifier”. In case the media (audio or video) carried by the Systems layer are different from MPEG, the format identifier indicates which of the registered formats is being actually used.

Digital Television exploits Digital Storage Media Command and Control (DSM-CC) to set up a network connection (used by CATV services) and the carousel to send the content of a slowly changing information source that each receiver that happens to “tune-in” can acquire after some time.

MPEG-4 AVC has replaced MPEG-2 Video in many instances because of its superior compression performance. MPEG-H HEVC is also being used in different countries especially for Ultra High Definition (UHD) distribution. HEVC has the advantage of providing better compression that AVC. Additionally it supports High Dynamic Range (HDR) and Wider Colour Gamut (WCG).

MPEG-B Part 9 provides a specification for Common Encryption of MPEG-2 Transport Streams.

MPEG-H part 1 MPEG Media Transport (MMT), replaces the original MPEG-2 Transport Stream. MMT is part of the ATSC 3.0 specification.

Digital Audio Broadcasting

In the mid-1990’s different European countries began to launch Digital Audio Broadcasting services based on the specifications of the Eureka 147 (EU 147) research project. EU 147 used MPEG-1 Audio Layer II as compressed audio format, in addition to other EU 147-proper specifications. The specification were widely adopted in other countries outside of Europe promoted by the non-government organisation WorldDAB.

In 2006 the DAB+ specifications were released. DAB+ includes HE-AAC v2 and MPEG surround (MPEG-D Part 1).

Technologically connected to DAB for the transport layer, but addressing video (AVC), is the Digital Multimedia Broadcasting (DMB) system developed by Korea for video transmission on mobile handsets.

Other audio services, such as XM, use HE-AAC.

Digital Audio

MP3 (MPEG-1 Audio Layer III) brought a revolution in the music world because it triggered new ways to distribute and enjoy music content. MP3 players continued the revolution brought about by the Walkman. Different versions of AAC continued that trend and triggered the birth of music distribution over the internet. Today most music is distributed via the internet using MPEG standards.

Digital Video for package media distribution

Video Compact Disc (VCD)

The original target of MPEG-1 – interactive video on compact disc – did not happen but, especially in Far East markets, VCD was a big success – probably 1 billion devices sold – anticipating the coming of the more performing but more complex MPEG-2 based DVD. VCD used MPEG-1 Systems, Video and Audio Layer II.

Digital Versatile Disc (DVD)

The widely successful DVD specification used MPEG-2 Video, MPEG-2 Program Stream and a selection of audio codecs for different world regions.

Blu-ray Disc (BD)

The BD specification makes reference to AVC and to Multiview Video Coding. MPEG-2 TS is used instead of MPEG-2 PS. Apparently, no MPEG audio codecs are supported.

Ultra HD Blu-ray

The specification supports 4K UHD video encoded in HEVC with 10-bit High Dynamic Range and Wider Colour Gamut.

Digital video for the studio

MPEG was born to serve the “last mile” of video distribution, but some companies requested to make a version of MPEG-2 targeting studio use. This is the origin of the MPEG-2 4:2:2 profile which only supports intraframe coding and a higher number of bits per pixels.

All standards following MPEG-2, starting from MPEG-4 Visual, have had a few profiles dedicates to use in the studio.

Not strictly in the video coding area is the Audio-Visual Description Profile (AVDP), defined in MPEG-7 Part 9. AVDP was developed to facilitate the introduction of automatic information extraction tools in media production, through the definition of a common format for the exchange of the metadata they generate, e.g. shot/scene detection, face recognition/tracking, speech recognition, copy detection and summarisation, etc.

Digital video

Repeating the “MP3 use case for video” was the ambition of many. MPEG-4 Visual provided the standard technology for doing it. DivX (a company) took over the spec and triggered the birth of “DVD-to-video file” industry that attracted significant attention for some time.

Video distribution over the internet

MPEG-4 Visual was the first video coding standard designed to be “IT-friendly”. Some companies started plans to deliver video over the then internet then growing (in bitrate). Those plans suffered a deadly blow with the publication of the MPEG-4 Visual licensing terms with the “content fee” clause.

The more relaxed AVC licensing terms favoured the development of MPEG-standard based internet-based video distribution. Unfortunately, the years lost with the MPEG-4 Visual licensing terms gave time to alternative proprietary video codecs to consolidate their position in the market.

A similar story continues with HEVC whose licensing terms are of concern to many not for what they say, but for what some patent holders do not say (because they do not provide licensing terms).

Not strictly in the video coding area, but extremely important for video distribution over the internet, is Dynamic Adaptive Streaming for HTTP. DASH enables a client to request a server to send a video segment of the quality that can be streamed on the bandwidth available at a particular time, as measured by client.

In the same space MPEG produced the Common Media Applic­ation Format (CMAF) standard. Several technologies drawn from different MPEG standards are restricted and integrated to enable efficient delivery of large scale, possibly protected, video applications, e.g. streaming of televised events. CMAF Segments can be delivered once to edge servers in content delivery networks (CDN), then accessed from cache by streaming video players without additional network backbone traffic or transmission delay.

File Format

To be “IT-friendly” MPEG-4 needed a file format and this is exactly what MPEG has provided

The MP4 File Format, officially called ISO Base Media File Format (ISO BMFF), was the MPEG response to the need. It can be used for editing, HTTP streaming and broadcasting.

MP4 FF contains tracks for each media type (audio, video etc.), with additional information: a four-character the media type ‘name’ with all parameters needed by the media type decoder. “Track selection data” helps a decoder identify what aspect of a track can be used and to determine which alternatives are available.

An important support to the file format is the Common Encryption for files provided by MPEG-B Part 7.

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