ALEXANDRIA, VA. When we discuss video compression such as MPEG-2 and H.264, most of us tend to think of the video aspects and don't think much about the audio. Sure, audio is important, but it's just there.
Now that there is a strong push to move beyond MPEG-4/H.264 compression now used for Blu-ray disks and many camcorders, we should spend a little time looking at the audio features of the next-generation of video encoding. The most likely next-generation codec for widespread use is HEVC (high efficiency video coding), which is also known by its ITU designation of H.265. Keep in mind that this is a video codec, and not an audio codec. The audio encoding that will accompany HEVC is being worked on by different teams than those working on HEVC/H.265.
There is a competitive compression standard being developed by Google called VP9, which will be built into many Web browsers. Available with no royalty payments, Google's vision for VP9 is that it will have better performance both in terms of encoding efficiency and image quality as compared to HEVC/H.265. Still, H.265 looks to be where professional and broadcast video are going in the next couple of years, despite the fact that royalty payments are associated with the standard.
There is yet another next-generation video codec on the near horizon, called Daala, being developed by the Xiph.Org Foundation and Mozilla Corp. The founder of Xiph.Org has stated that the performance of Daala should be a generation beyond HEVC and VP9, but an initial release is not expected in 2015. Interestingly, the Xiph.Org Foundation is the creator of FLAC (free lossless audio codec), which is well-regarded for its audio performance.
TWICE AS EFFICIENT
From a video standpoint, H.265 is roughly twice as efficient as H.264, which was itself about twice as efficient as MPEG-2. In other words, a video stream encoded at 20 Mbps with MPEG-2 would require about 10 Mbps with H.264 and about 5 Mbps with H.265. That's a little oversimplified, but it's a useful rule of thumb.
MPEG-2 introduced most of us to the term MP3 for audio coding. Unveiled with MPEG-1 compression in the early 1990s, MP3 stands for MPEG Audio Layer III. It has become a popular audio compression standard, although there are many others also in use simultaneously. Like the parent video compression standard, MP3 is a lossy form of compression, meaning that it changes the audio in order to achieve its compression and those changes can't be undone once they are compressed.
MP3 has a wide range of settings that have an effect on the final audio quality, including sampling rate and bit-rate. Mainstream MP3 can be sampled at 32, 44.1 and 48 kHz rates, and can be encoded at bit-rates ranging from 56 to 384 kbps. At 128 kbps and 44.1 kHz sampling, an MP3 file takes up about 9.1 percent of an uncompressed CD recording. Encoding an MP3 file at a bit-rate of 320 kbps will create a bitstream that's about 23 percent the size of an uncompressed CD recording.
Advanced audio coding (AAC) was developed after MP3 and takes advantage of what was learned from that initial popular format. AAC generally provides better sound quality as MP3 at similar bit-rates. AAC also has an offshoot known as high efficiency advanced audio coding (HE-AAC), which is used for mobile television standards such as DVB-H and ATSC-M/H. Like MP3, AAC is a lossy compression format, and it has a range of settings similar to MP3.
Dolby Digital and AC-3 are two names for the same format of audio processing. Developed by Dolby Laboratories, AC-3 is sometimes referred to as audio codec 3 or advanced codec 3. All forms of AC-3 support surround sound, with the initial version carrying 5.1 channels and the later Dolby Digital Plus handling 7.1 channels. An enhancement to Dolby Digital Plus called E-AC-3 can carry up to 13.1 channels. The greater coding efficiency of E-AC-3 means that it can provide reasonable 5.1-channel audio in a 256 kbps stream.
NEXT-GEN AUDIO FORMATS
The primary audio coding formats associated with HEVC/H.265 are MPEG-H and AC-4, and may also include other codecs over the ensuing months. MPEG-H can be thought of as AAC on steroids, and last year the ATSC announced that MPEG-H 3D audio was one of the three standards proposed for the audio system of ATSC 3.0. In its simplest form, MPEG-H will support eight channels of audio. It has many other features, including the ability to provide loudness metadata.
Dolby AC-4 is likewise a considerably advanced codec that evolved from AC-3. Compared to AC-3, AC-4 improves compression efficiency for broadcast by about 50 percent. AC-4 is already standardized with the European Telecommunications Standards Institute and adopted by the Digital Video Broadcasting Project, the U.K. standards body. The standard features native support for dialogue enhancement, intelligent loudness and advanced dynamic range control, as well as more efficient support for multiple languages and descriptive services.
The interaction of these audio codecs with HEVC is still being worked out and will become part of a final ATSC standard here in the United States. At the recent ATSC Boot Camp in Washington, Jim Starzynski of NBC gave a presentation on the status of MPEG-H and what we can expect in the future.
Like video codecs, audio codecs are becoming more efficient at compressing audio into smaller streams. This will enable future broadcast codecs to provide more channels of audio and provide broadcasters with more choice regarding quantity vs. quality trade-offs.
Most recent headlines
11/12/2025
Dalet, a leading provider of cloud-native, end-to-end media workflow solutions, ...
05/12/2025
2025 Sports Broadcasting Hall of Fame: Curt Gowdy Jr. - Master Storyteller, Nati...
05/12/2025
SVG Sit-Down: Veritone's Sean King on the Power of Mining Video, Audio DataThe company's Data Refinery offers users total control and governance over da...
05/12/2025
Platinum White Paper: Inside the Nashville Predators' Unified, Flexible, Sca...
05/12/2025
Netflix Reaches Agreement To Acquire Warner Bros. Following Planned WBD SplitThe deal does not include WBDs sports assets like TNT Sports (US, UK, LatAm), Euros...
05/12/2025
FOX Sports Returns to Indianapolis for Primetime Broadcast of Big Ten Championsh...
05/12/2025
SVG Summit 2025 Preview: Digital Engagement & Monetization Workshop Tackles the ...
05/12/2025
Atlanta United Lights Up New Emory Healthcare Studio With First Live Broadcast f...
05/12/2025
As Messi Takes the Pitch, MLS, Apple, NEP Roll Out Largest MLS Cup Production Ev...
05/12/2025
ESPN Enters College Football's Most Intense Month With Elevated Workflows fo...
05/12/2025
It's about that time! Awards season is in full swing, and the Film Independe...
05/12/2025
Every year, Spotify Wrapped offers a personalized look back at the audio that defined your year. It's a snapshot of your listening habits, designed to tell ...
05/12/2025
In 2025, Spotify's EQUAL, GLOW, and RADAR programs celebrated women, LGBTQIA , and emerging artists who turned moments into milestones. From breaking record...
05/12/2025
In our latest blog, we explain how Wi-Fi 7 rollouts can drive consumer loyalty with value-add services such as consumer cybersecurity. We also explore how this ...
05/12/2025
LOS ANGELES Netflix announced it has entered into an agreement to acquire the assets of Warner Bros. for $82.7 billion....
05/12/2025
NEW YORK Nielsens Gracenote has launched Gracenote Content Connect, a new ad platform that provides agencies, brands, supply-side platforms (SSPs) and demand-si...
05/12/2025
NEW YORK In an most important update to the workings of deal-based programmatic advertising, IAB Tech Lab has released version 1.0 of its Deals API for public c...
05/12/2025
NEW YORK Pass the turkey. Pass the stuffing. Pass the cranberry sauce. All are common requests of Americans celebrating Thanksgiving Day with family and f...
05/12/2025
NEW YORK Iris, the new cloud-connected camera control platform, has officially launched with features that turn virtually any PTZ camera into a software-connect...
05/12/2025
HOLLYWOOD, Calif. Netflix announced today that it has entered into an agreement to acquire the assets of Warner Bros. for $82.7 billion....
05/12/2025
NEW YORK Iris, the new cloud-connected camera control platform, has officially launched with features that turn virtually any PTZ camera into a software-connect...
05/12/2025
WASHINGTON The Federal Communications Commission has approved AT&T's $1.02 billion acquisition of spectrum from UScellular in a decision that was issued sho...
05/12/2025
The Best Coldplay Songs: 21 Tracks That Shoot for the Stars From Yellow to Viva La Vida, Fix You to Paradise, this playlist goes back to the start.
December ...
05/12/2025
Zafris Lecture Series Brings Nabil Ayers to Berklee The 32nd annual James G. Zafris Distinguished Lecture series was held on Thursday, November 13 with guest ...
05/12/2025
Friday 5 December 2025
A new Game of Thrones Tale: Official trailer for Sky Exc...
05/12/2025
Back to All News
Don Lee, Lee Jin-uk, and Lalisa Manobal to Star in Netflix Act...
05/12/2025
Tis the season of giving once again and this year we've taken our Give Back Fridays' concept and turned it on its head.
In the autumn we were approach...
05/12/2025
Brayden Gogis doesn't remember a time when he wasn't completely fixated on games in all forms. In preschool, when they asked us to dress up as what we ...
05/12/2025
The Grinch steals the spotlight as the theme for The Late Late Toy Show 2025
Tune in tonight at 9:35pm on RT One and worldwide on RT Player
#LateLateToyShow...
05/12/2025
RT Announces New Presenters of Flagship News Programmes
New RT Six One News co-presenter Tommy Meskill
Sarah McInerney & Justin McCarthy join Morning Ir...
04/12/2025
ToolsOnAir Blackmagic Design HyperDeck Event Presets for just:in mac pro 2025 & ...
04/12/2025
ToolsOnAir AJA Ki Pro Event Presets for just:in mac pro 2025 & just:in linux
More Details:Starting with version 5.5, both just:in mac pro and just:in linux sol...
04/12/2025
Wangu Kanuri from Kenya and Godwin Asediba from Ghana are two of this years finalists for Thomsons Young Journalist of the Year Award. The pair are runners-up i...
04/12/2025
SVG Sit-Down: ProximaVision's Claudio Lisman on Why Tethered Drones Could Be...
04/12/2025
SVG Campus Shot Callers: Imry Halevi, Senior Associate Director of Athletics, Co...
04/12/2025
Platinum White Paper: LiveU Lightweight Sports Production: A Step Change in Spor...
04/12/2025
London to Riyadh: DAZN brings the boxing glamour to new production levels for Be...
04/12/2025
Analysis: Paramount bets on the battering ram' with Champions League play By Callum McCarthy, Editor-at-Large
Tuesday, December 2, 2025 - 10:12
Print ...
04/12/2025
Space City Home Network Launches SCHN DTC App for Astros and RocketsThe Rockets and Astros were previously the lone NBA and MLB teams without a DTC appBy Jason...
04/12/2025
SVG Summit 2025 Preview: Content Workflows Workshop Spotlights Evolution of Spor...
04/12/2025
New Sponsor Spotlight: Geotech's Patrick Wambold On the Unreal Engine Revolu...
04/12/2025
Curt Gowdy Jr. - Master Storyteller, Nationally and RegionallyBy Jason Dachman, Editorial Director, U.S.
Thursday, December 4, 2025 - 1:52 pm
Print This Sto...
04/12/2025
(L-R) Rebecca Lichtenfeld, Mohammadreza Eyni, Sara Khaki, and Judith Helfand att...
04/12/2025
SBS launches Future Frames initiative to support emerging First Nations video ed...
04/12/2025
Coronal mass ejections caused by eruptions on the surface of the sun can have fa...
04/12/2025
Gracenote Content Connect enables media ecosystem to precisely align ad campaigns and programming based on rich content signals
NEW YORK - December 4, 2025 - N...
04/12/2025
Lightware, a global specialist in AV connectivity, is looking back on a year defined by new advancements, strong collaboration and continued growth. Across the ...
04/12/2025
Riedel Communications today announced a new partnership with Haivision, a leading global provider of mission-critical, real-time video networking and visual col...
04/12/2025
Harmonic (NASDAQ: HLIT) and Normann Engineering today announced a major milestone in their strategic collaboration, celebrating 20 successful broadband deployme...
ALEXANDRIA, VA. When we discuss video compression such as MPEG-2 and H.264, most of us tend to think of the video aspects and don't think much about the audio. Sure, audio is important, but it's just there.
