aware(5)aware(5)NAME
aware, AwareIntro - Aware(R), Inc. scalable audio compression software
engines
Aware Compression
Aware has implemented audio compression software engines enabling users
of Silicon Graphics(R) workstations to reduce the storage size and
transmission bandwidth required for audio data. The products are
compatible with third-party applications which incorporate audio in the
Silicon Graphics computing environment. Scalable operation provides the
ability to control processor loading for audio playback concurrent with
other computational tasks.
MPEG Audio Compression Engine
Aware scalable MPEG (Motion Pictures Experts Group) compression software
provides advanced psychoacoustic processing for compression of high
quality audio (up to 48 kHz sampling rate) in authoring, publishing, and
large audio database applications.
Real-time operation encodes audio while recording and provides moderate
compression ratios. Non-real-time operation invokes advanced
psychoacoustic modeling for high compression ratios. Encoding bit-rates
range from 32 kbits/second to 448 kbits per second (corresponding to
compression ratios as high as 48:1).
The software MPEG decompression engine is included as a standard feature
of the IRIS Digital Media Execution Environment (dmedia_eoe). Standard
tools like soundplayer(1) and movieplayer(1) use this software to play
back MPEG audio tracks.
The software MPEG compression engine is also included with the IRIS
Digital Media Execution Environment (dmedia_eoe). Standard tools like
soundeditor(1) and soundtrack(1) use this software to record MPEG audio
tracks.
Aware MultiRate (TM) Compression Engine
Aware MultiRate compression provides a compression solution for studio
and audio production applications requiring lossless (perfectly
invertible) and near-lossless coding and using low processor loading.
Lossless mode typically reduces storage requirements by 2:1 to 3:1.
Near-lossless operation achieves even greater storage savings while
retaining a 90 dB signal to noise ratio. Real-time encoding of audio at
8, 11, 16, 22, and 44.1 kHz sampling rates is supported. Scalable
encoding and decoding operation provides control of processor loading
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during playback. Installation of AudioProducer includes Aware's
AudioPlayback software.
The MultiRate decoder runs in real-time at sampling rates up to 48 kHz.
Installation of the decoder enables real-time playback of compressed
audio which was encoded with the Aware AudioPublisher or the Aware
AudioProducer. Scalable decoding operation provides the ability to
control processor loading used for playback, and enables special
functions such as fast playback to speed search through compressed audio
libraries.
The software necessary to perform Aware MultiRate audio compression or
decompression is included with the standard IRIS Digital Media Execution
Environment (dmedia_eoe). However, both of these engines are locked by
default. You must obtain a license from Aware in order to unlock the
compression or decompression engines.
Please note that as of Irix 6.x, Aware no longer sells licenses for the
MultiRate audio codec. SGI still provides the libraries for backwards
compatibility, and as a convenience to users who have previously
purchased MultiRate audio codec licenses from Aware.
MPEG Audio Compression Specifications
Algorithm:
ISO/MPEG Layer I and II low bitrate psychoacoustic compression
Developer Support:
Audio File Library (AFaware(3dm))
Compression Library (CLintro(3dm))
Encoder Input:
Format
16 bit linear audio samples, mono or stereo
Sample Rates
48, 44.1, 32 kHz
Decoder Output:
Format
16 bit linear audio samples, mono or stereo
Sample Rates
48, 44.1, 32, 24, 22.05, 16, 11.025
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Compression Ratios:
2.2:1 to 48:1, selectable via bitrate parameter
Bitrates (kbits/sec):
Layer I:
32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384,
416, 448
Layer II:
32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320,
384
Channel Processing:
mono, stereo, joint stereo, dual channel
Scalable Processing:
Controlled reduction of CPU usage by parametric control of
frequency response, signal to noise ratio, and mono decoding of
stereo.
Aware MultiRate Compression Specifications
Algorithm:
Aware MultiRate I high resolution audio compression
Developer Support:
Audio File Library (AFaware(3dm))
Compression Library (CLintro(3dm))
Encoder Input:
Format
16 bit linear audio samples, mono or stereo
Sample Rates
48, 44.1, 32, 22.05, 16, 11.025, 8 kHz
Decoder Output:
Format
16 bit linear audio samples, mono or stereo
Sample Rates
48, 44.1, 32, 24, 22.05, 16, 11.025, 8 kHz
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Compression Ratios:
MultiRate lossless (perfectly invertible mode):
2:1 to 3:1 typical
MultiRate near lossless (90+dB SNR) mode:
2.5:1 to 4:1 typical
Channel Processing:
mono, stereo, dual channel
Scalable Processing:
Controlled reduction of CPU usage by parametric control of
frequency response, signal to noise ratio, and mono decoding of
stereo.
SEE ALSOMPEG(4)soundplayer(1), movieplayer(1), moviemaster(1),
AFintro(3dm), AFaware(3dm), CLintro(3dm), CLaware(3dm),
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