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
06/10/2025
France T l visions, France's leading broadcaster, has received the 2025 EBU ...
04/09/2025
Monumental Sports & Entertainment (MSE), in collaboration with Dalet, has been a...
30/08/2025
WASHINGTON The Federal Communications Commission has adopted its FY 2025 Regulatory Fees Order that establishes the regulatory fee rates for the broadcast stati...
29/08/2025
Australian Red Cross and SBS launch training to help workplaces in the fight aga...
29/08/2025
The National Film and Video Foundation (NFVF), an agency of the Department of Sp...
29/08/2025
L3Harris Technologies has concentrated decades of expertise across the entire enterprise to develop affordable and reliable best-of-breed solutions to rapidly c...
29/08/2025
BURBANK, Calif. The CW Network and the Pac-12 Conference have announced a new media rights deal that will extend their broadcast partnership beginning with the ...
29/08/2025
NEW YORK Gracenote has released a new analysis of its global video dataset showing that the number of FAST channels grew nearly 14% from Q1 2025 and 76% since 2...
29/08/2025
SAN JOSE, Calif. Harmonic has announced a series of improvements to its live sports streaming solution that the company said will improve fan engagement, protec...
29/08/2025
NEW YORK and LOS ANGELES Fox Corp. and YouTube TV last night announced a renewal of the full portfolio of Fox networks, including Fox News Channel, Fox Business...
29/08/2025
Budapest, Hungary, August 2025 - The integration of Microsoft Teams Rooms (MTR) with Lightware's Taurus universal matrix switchers delivers a new level of f...
29/08/2025
Frequency, the engine behind many of the world's best-known streaming television channels, today announced it will launch Studio Live, a next-generation uni...
29/08/2025
In an era when AI and cyber resilience are essential, Scality will mark the 10th anniversary of Scality Day on October 16, 2025 in Paris. This flagship global e...
29/08/2025
Disguise's In-House Creative and Technical Teams Pre-Visualised, Programmed and Delivered Content for the Experience, All Powered by EX 3+
Technology solu...
29/08/2025
Disguise will be demonstrating the latest workflows for TV, film and live events on a number of partner booths at the show
Disguise, the industry-leading tech...
29/08/2025
STOCKHOLM, Sweden Accedo will showcase Accedo Compose, its AI agent-powered modular orchestration layer that assists streaming providers in transitioning client...
29/08/2025
LOS ANGELES Cineverse has announced that it is working with Xperi to bring four of its streaming channels to automobiles for the first time as part of the DTS A...
29/08/2025
DALLAS & ATLANTA Gray Media has announced an agreement with the sports streaming service Victory+ to simulcast 17 Dallas Stars NHL games in 15 television market...
29/08/2025
NEW YORK AND CULVER CITY Comcast NBCUniversal and Amazon have announced new and extended distribution agreements that will expand the content available on their...
29/08/2025
FOOTHILL RANCH, Calif. RED Digital Cinema will feature its Cine-Broadcast Module supporting live broadcast workflows during IBC2025, Sept. 12-15, at the RAI Ams...
29/08/2025
29 Aug 2025
Kyivstar Rings Opening Bell at Nasdaq Marking Landmark Listing and ...
29/08/2025
More than half of all NFL games live on Sky for the first timeFriday 29 August 2025
Sky Sports has announced a new three-year deal with the NFL, extending its ...
29/08/2025
Back to All News
RIV4LRIES: The Trailer of the New Series With Samuele Carrino ...
29/08/2025
Get ready for an inspiring and emotional insight into the world of competitive Irish dancing with My Story: Tomi Champion of the World airing on RT 2 this monda...
29/08/2025
RT has today announced that David McCullagh is to be the new presenter of RT Radio 1's flagship Today programme, which airs every weekday at 10am, replaci...
28/08/2025
By Kristin Feeley, Director, Documentary Film & Artist Programs
If you want to tell untold stories, if you want to give voice to the voiceless, you've got ...
28/08/2025
Directed by Steven Bognar and Julia Reichert, Sundance Institute-supported Amer...
28/08/2025
Corridos have been a cornerstone of M sica Mexicana for generations, telling stories rooted in everyday life. Now, a new chapter is taking shape: motivational c...
28/08/2025
Los corridos han sido un pilar de la M sica Mexicana durante generaciones, contando historias enraizadas en la vida cotidiana. Ahora, un nuevo cap tulo est tom...
28/08/2025
Earlier this month, we promised our Verano Forever party would bring the heat, a...
28/08/2025
L3Harris will provide the Polish F-16V fleet with the Viper Shield electronic warfare system as part of an upgrade program....
28/08/2025
Bilbao, August 26, 2025 - AgileTV, an international television and video technol...
28/08/2025
Ken Wilkinson is an Emmy Awards nominated New York audio engineer who specialises in production sound mixing for film, commercial, episodic and documentary work...
28/08/2025
NEW YORK FuboTV today announced that it will launch Fubo Sports, a skinny bundle that focuses on sports with a subscription price of $56 monthly....
28/08/2025
NEVADA City, Calif. At IBC2025, Sept. 12-15 at the RAI Amsterdam, Telestream will debut its new Global Ingest strategy, introducing a next-generation ingest arc...
28/08/2025
Dr. Rhoda Bernard Releases Groundbreaking Debut Book on Accessible Arts Educatio...
28/08/2025
TAG Video Systems, the leader in software-based IP end-to-end workflow monitoring, deep probing, and real-time visualization, has named Oliver Gappa as Sales Di...
28/08/2025
AI-based voice enhancement will be among a series of innovations making their IBC 2025 debut on the DHD stand B46 in Hall 8 at the RAI Amsterdam Convention Cent...
28/08/2025
Telef nica Servicios Audiovisuales (TSA), the leading system integrator and service provider in the media sector in Spain, with the support of Appear, the globa...
28/08/2025
To fully immerse sailing fans in the world's biggest offshore yacht race, production company, Optical Media turned to LiveU's On-site Production solutio...
28/08/2025
Working with Calrec on its most recent overhaul, radio and television broadcaster, WNED has migrated to a fully IP infrastructure with multiple Type R consoles,...
28/08/2025
Cleeng, the Subscriber Retention Management (SRM ) inventor, has unveiled Cleeng Pro, the first-ever direct-to-consumer (D2C) subscription management platform t...
28/08/2025
Zixi, the industry leader in live broadcast-quality video over IP, today announced that French media distribution platform OKAST has selected Zixi to enable rel...
28/08/2025
Solution offers a streamlined, speaker-free architecture to optimize integration with premium external loudspeakers and advanced loudness metering
Nixer Pro Au...
28/08/2025
Cinegy, the premier provider of software-defined television technology, has announced a strategic partnership with Vision One Touch Film Production Services L.L...
28/08/2025
Telestream, a global leader in media workflow technologies, will debut its new Global Ingest strategy at IBC2025, introducing a next-generation ingest architect...
28/08/2025
Tier 1 operator selects Broadpeak to power high-performance, unified CDN solution across Norway, Sweden and Finland
Broadpeak, a leader in streaming and moneti...
28/08/2025
Leading video software provider, Synamedia, today announced that 24 Frames Digital, one of India's leading live event streaming service providers, has chose...
28/08/2025
Meet VisualOn at IBC2025: See What's Next in AI-Powered Video Streaming Join VisualOn at IBC2025 and discover how our AI-driven Optimizer and advanced media...
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.
