White Papers and Documents
Audio
apt-X Lossless
There exist numerous schemes – the results of development activity over many years in both the academic and commercial fields, and within the wider open source community – for the so-called lossless compression of digital audio. These schemes, which include, for example, Apple Lossless [1], Free Lossless Audio Codec (aka FLAC) [2], and recently, mp3HD [3], are typically applied to gain useful economies through the data reduction (“compression”) in the bulk size of archived audio files (mainly music, but also speech) held in storage on, usually, a computer hard-disk drive (HDD), dedicated file server, or on solid-state memory device (e.g., Flash memory) and other portable mass-storage systems, including read/writeable optical media (CD-ROM, DVD, DVD-HD, Blue-ray, etc). These various formats are described and compared elsewhere [4].
Publish Date: 2 Jun, 2010
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Low Bit-Rate Audio Coding in Multi-channel Digital Wireless Microphone Systems
Despite advances in voice and data communications in other domains, sound production for live events (concerts, theatre, conferences, sports, worship, etc) still largely depends on spectrum-inefficient forms of analogue wireless microphone technology. In these live scenarios, low-latency transmission of high-quality audio is mission critical. However, while demand increases for wireless audio channels (for microphones, in-ear monitoring and talkback systems), some of the radio bands available for “Programme Making and Special Events” are to be re-assigned for new wireless mobile telephony and Internet connectivity services: the FCC recently decided to permit so-called White Space Devices to operate in sections of UHF spectrum previously reserved for shared use by analogue TV and wireless microphones. This paper examines the key performance aspects of low bit rate audio codecs for the next generation of bandwidth-efficient digital wireless microphone systems that meet the future needs of live events.
Publish Date: 2 Jun, 2010
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Livening up surround-sound in digital television
One of the many advantages of HDTV is the ability to broadcast multi-channel audio and allow listeners to immerse themselves in a true surround-sound experience. However, it would be true to say that the audio portion in HDTV has been the poor relation when compared to the video component. Further development in video is slowing and suffering from the laws of diminishing returns with regards to engineering input versus return on investment. In contrast, the audio component is virtually a virgin territory as can be witnessed by the limited number of options currently available for broadcast, acquisition, production and processing.
Publish Date: 2 Jun, 2010
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Viable distribution of Multi-channel Audio-over-IP for Live and Interactive “Voice Talent” based Gaming using High-quality, Low-latency Audio Codec technology
The delivery of multi-channel audio – from mono to surround sound – in real-time over public IP networks for the purpose of interactive crowd-participant gaming presents a significant design engineering challenge to games developers, console manufacturers, ISPs and CDNs. Leveraging expertise gained in professional broadcasting and recording studio post-production, APT has developed a robust and scalable audio codec technology that meshes with popular gaming systems to realize low-latency distribution of high-quality audio for immersive, instantaneous audio experiences in massively multi-player online games involving interactive audience responses.
Publish Date: 3 Nov, 2009
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