ETSI releases AC-4, the new generation audio codec standard
Sophia Antipolis, 29 April 2014
Flexible, cost effective and enhanced experience for industry and end-users
ETSI, the leading ICT standards organization, has released this month AC-4 the next generation digital audio compression standard for tomorrow’s media delivery environments, offering the flexibility to support future audio experiences.
From TVs to home theatres, from computers to mobile phones and online streaming, this innovative codec offers an advanced sound experience for all users’ entertainment including video games. New advanced features are designed for the multi-channel, multiple devices environment of our “digital natives” era.
“Our broad representation of industry stakeholders in ETSI allows us to offer new solutions as technologies and consumer usage evolve”, says Simon Fell, Chairman of ETSI Broadcast Technical Committee. “AC-4 is designed to be an advanced standard for both audio for video and audio-only delivery. The specification meets modern entertainment requirements with features to simplify the synchronization of audio and video, to take into account adaptive streaming, complex audio sets, and a very rich support for metadata.”
After the widespread and popular AC-3 format, the AC-4 audio codec standard, ETSI TS 103 190, is designed by industry experts to go beyond providing simple compression efficiency. AC-4 enables new, more immersive and personalized consumer audio experiences in the future. Users will be able to hear what the football match sounds like from the stands or the field and experience the kind of sound that transports them right to the centre of the action, whether they are playing a game or watching a movie.
Solving several key issues currently facing the industry, the main benefits of AC-4 include:
- Intelligent Loudness: Fully automated loudness management means more precise control and eliminates problems with cascaded processing. It acts across a wide range of devices and applications (home theatre to mobile) and can be configured to align with numerous worldwide standards and/or recommendations.
- Advanced Dialogue Enhancement: End-users can have control of the dialogue level in relation to other sounds in the programme - suiting individual hearing needs and preferences.
- Advanced Accessibility: Service providers can easily and efficiently deliver secondary audio in 5.1 surround sound for the visually impaired without doubling the file size or bitrate.
- A/V Frame Alignment: AC-4 is the first emission audio format that allows the audio frame sizes to precisely match the video frame size. This allows the AC-4 data stream to be edited/spliced at video frame boundaries to maintain synchronization without the need to decode and re-encode the audio.
- Bandwidth Efficiency: AC-4 utilizes state-of-the-art compression techniques that provide significant bandwidth savings or higher quality in stereo and surround sound
ETSI produces globally-applicable standards for Information and Communications Technologies (ICT), including fixed, mobile, radio, converged, aeronautical, broadcast and internet technologies and is officially recognized by the European Union as a European Standards Organization. ETSI is an independent, not-for-profit association whose more than 700 member companies and organizations, drawn from 63 countries across 5 continents worldwide, determine its work programme and participate directly in its work.
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