AES69-2020, "AES standard for file exchange – Spatial acoustic data file format", a revised version of AES69-2015 has been published.
Posted on February 4, 2021 at 6:00:00 AM EST
This standard provides a convention for expressing edit data in text form in a manner that enables simple and accurate computer parsing while retaining human readability. It also describes a method for expressing time-code information in character notation. It supports common professional audio sampling frequencies, video frame rates, and film framing. This document addresses the core need of the AES31 series of standards in providing a simple but extensible system for passing audio material between systems.
The SMPTE Universal Label identified in Annex F.2 was provided by SMPTE as a Leaf in the metadata dictionary for 'Audio edit decision list (ADL) defined in AES31-3'. Also defined is a Node in the metadata dictionary for 'File exchange metadata defined in AES standards'. This means that further file-exchange labels can be generated more easily in the future.
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Posted on December 22, 2020 at 6:00:00 AM EST
The question of sample-clock quality is a perennial one for digital audio equipment designers, yet most chip makers provide very little information about the jitter performance of their products. Consequently, equipment designers are sometimes caught out by jitter issues. The increasing use of packet-based communications and class-D amplification is throwing these matters into sharper relief. This information document reviews various ways of characterizing and quantifying jitter, and refines several of them for audio purposes. It also attempts to present a common, unambiguous terminology. Its focus includes wideband jitter, baseband jitter, jitter spectra, period jitter, long-term jitter and jitter signatures. Comments are made on jitter transfer through phase-locked loops and on the jitter susceptibility of audio converters.
This revision removes culturally insensitive terms from the text and corrects minor editorial issues. It is available now in the Standards Store.
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Posted on December 16, 2020 at 6:00:00 AM EST
AES17 defines a digital Full Scale and 0 dB FS as the level of a sinewave whose peaks reach the largest positive digital code. Some incorrectly display full scale sinewaves as -3 dB FS. The AES17-2020 revision is an effort to eliminate this confusion.
Originally released in 1991, AES17 introduced and defined the measurement of 0 dB FS. This definition has remained unchanged through revisions of the standard in 1996, 1998 and 2015. The 2015 revision added notes to clarify the proper calibration of dB FS. The 2020 revision further expands on these notes.
The 2020 revision will be available for download on 2020/12/11
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Posted on December 9, 2020 at 6:00:00 AM EST
The Call for Comment on DRAFT AES69-2020, " AES standard for file exchange – Spatial acoustic data file format " was published 2020-12-08.
Binaural listening is growing fast, because of growing sales in smartphones, tablets and other individual entertainment systems. The lack of a standard for the exchange of head-related transfer functions (HRTF) means each company keeps its binaural capture and rendering algorithms private. 3D audio is arising, and binaural listening could be the very first 3D audio vector with sufficient fidelity of HRTF.
The use of convolution-based reverberation processors in 3D virtual audio environments has grown with the increase in available computing power. Convolution-based reverberators guarantee an authentic and natural listening experience, but also depend on the acoustic quality of the applied spatial room impulse response (SRIR).
With a standardized file format for HRTF and SRIR data, each company can contribute its best algorithms, providing good personalized capture and/or rendering, allowing the consumer to choose a combination of technologies for the best quality of experience.
This document standardizes a file format to exchange space-related acoustic data, such as binaural listening parameters in the form of head related transfer functions. The format is scalable to match the available rendering process and is designed to include source materials from different databases.
Posted on December 6, 2020 at 6:00:00 AM EST
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