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Data compression -
1 Other types of lossy compressors, such as the linear predictive coding (LPC) used with speech, are source-
based coders
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GSM - Voice codecs
1 These used a system based on linear predictive
coding (LPC)
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MP3 - Development
1 Manfred Schroeder was already a well-known and revered figure in the worldwide community of acoustical
and electrical engineers, but his paper was not much noticed, since it described negative results due to the particular nature of speech and the linear predictive coding (LPC) gain
present in speech
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Perception - Effect of motivation and expectation
1 Instead, our brains use what he calls Predictive
coding
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Bayesian approaches to brain function - Predictive coding
1 Predictive coding is a neurobiologically plausible scheme for inferring the causes of
sensory input based on minimizing prediction error.Rao RPN, Ballard DH.
Predictive coding in the visual cortex: a functional interpretation of some extra-classical receptive-field effects. Nature
Neuroscience. 1999. 2:79–87 These schemes are related formally to Kalman
filtering and other Bayesian update schemes.
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Bayesian approaches to brain function - Free energy
1 This can be cast (in neurobiologically plausible terms) as predictive coding or, more generally, Bayesian filtering.
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Digital signal processor - History
1 In 1976, Richard Wiggins proposed the Speak Spell (toy)|Speak Spell concept to Paul Breedlove, Larry Brantingham, and Gene Frantz at Texas Instrument's Dallas research facility. Two years later in 1978
they produced the first Speak Spell, with the technological centerpiece being the
TMS5100, the industry's first digital signal processor. It also set other milestones, being the first chip to use Linear predictive coding
to perform speech synthesis.
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Silk (codec) - Details
1 Skype Limited announced that SILK can use a sampling frequency of 8, 12, 16 or 24kHz and a bit rate from 6 to 40 kbit/s. It can also use a low algorithmic latency (audio)|delay of 25 ms (20 ms frame size + 5 ms look-ahead). The reference implementation is
written in the C programming language. The codec technology is based on linear
predictive coding (LPC). The SILK executable|binary Software development
kit|SDK is available.https://store.theartofservice.com/the-predictive-coding-toolkit.html
MBONE - Mbone tools
1 * Audioconferencing: vat -t ttl destination-host/port (supports:
Linear predictive coding|LPC, PCMU, DVI4, GSM)
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Texas Instruments - First speech synthesis chip
1 This resulted in the development the TMC0280 one-chip Linear predictive coding (LPC) speech
synthesizer which was the first time a single silicon chip had electronically replicated the
human voice.[http://americanhistory.si.edu/archives/spee
chsynthesis/ss_ti.htm “Smithsonian Speech Synthesis History Project”], accessed September 7, 2008 This was used in several TI commercial
products beginning with Speak Spell (toy)|Speak Spell which was introduced at the Summer Consumer Electronics Show in June 1978
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Secure voice - Digital Methods using Voice Compression: MELP or MELPe
1 As part of NATO testing for new NATO standard, MELPe was tested against other candidates such as France's
HSX (Harmonic Stochastic eXcitation) and Turkey's SB-LPC (Split-Band
Linear Predictive Coding), as well as the old secure voice standards such
as FS1015 LPC-10e (2.4 kbit/s), FS1016 CELP (4.8 kbit/s) and CVSD
(16 kbit/s)https://store.theartofservice.com/the-predictive-coding-toolkit.html
Speech synthesis - Diphone synthesis
1 At runtime, the target prosody (linguistics)|prosody of a sentence is superimposed on these minimal units by means of digital signal processing techniques such as linear predictive
coding, PSOLA or MBROLA.T
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Manfred R. Schroeder
1 He joined the technical staff at Bell Labs in New Jersey (1954-)
researching speech and graphics, securing forty-five patents. With Bishnu Atal he was a promotor of
linear predictive coding (1967). Still affiliated with Bell, he rejoined
University of Göttingen as Universitätsprofessor Physik (1969)
becoming professor emeritus (1991).https://store.theartofservice.com/the-predictive-coding-toolkit.html
Multimedia Information Retrieval - Feature Extraction Methods
1 Typical methods include Linear Predictive Coding in the
audio/biosignal domain,HG Kim , N Moreau, T Sikora
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Video compression - Coding methods
1 Other types of lossy compressors, such as the linear predictive coding (LPC) used with speech, are source-
based coders
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Opus (audio format)
1 Opus can be adjusted seamlessly between high and low bit rate|
bitrates, and internally, it transitions between linear predictive coding at lower bitrates and transform coding
at higher bitrates (as well as a hybrid for a short overlap)
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Opus (audio format) - Features
1 The SILK layer that specializes in speech signals is based on linear predictive coding (LPC) and an
optional Long-Term Prediction filter
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High Efficiency Video Coding - Range extensions
1 **Residual DPCM (RDPCM), allowing a vertical or horizontal spatial-
predictive coding of residual data in transform skip and transform-
quantization bypass blocks (which can be selected for use in intra blocks, inter blocks, or both).
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Warped linear predictive coding
1 'Warped linear predictive coding' ('warped LPC' or 'WLPC') is a variant of linear predictive coding in which the
spectral representation of the system is modified, for example by replacing the unit delays used in an LPC implementation with
first-order allpass filters. This can have advantages in reducing the bitrate required
for a given level of perceived audio quality/intelligibility, especially in wideband
audio coding.https://store.theartofservice.com/the-predictive-coding-toolkit.html
Algebraic code-excited linear prediction
1 'Algebraic code-excited linear prediction' ('ACELP') is a patentedUS
Patent 5717825 Algebraic code-excited linear prediction speech coding method speech coding
algorithm by VoiceAge | VoiceAge Corporation in which a limited set of pulses is distributed as excitation to
a Linear predictive coding|linear prediction filter.
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Code-excited linear prediction
1 At the time, it provided significantly better quality than existing low bit-rate algorithms, such as residual-
excited linear prediction and linear predictive coding vocoders (e.g., FS-
1015)
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ILBC
1 The algorithm is a version of block-independent linear predictive coding, with the choice of data frame lengths
of 20 and 30 milliseconds
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Network Voice Protocol
1 NVP was used to send speech between distributed sites on the ARPANET using several different voice-encoding techniques, including linear predictive coding (LPC) and continuously
variable slope delta modulation (CVSD). Cooperating researchers included Steve Casner, Randy Cole, and Paul Raveling (ISI); Jim Forgie (Lincoln Laboratory); Mike McCammon (Culler-
Harrison); John Markel (Speech Communications Research Laboratory); and John Makhoul (Bolt,
Beranek and Newman).
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Line spectral pairs
1 'Line spectral pairs' ('LSP') or 'line spectral frequencies' ('LSF') are used to represent linear predictive coding|linear prediction coefficients
(LPC) for transmission over a channel
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Secure telephone - Historically significant products
1 In 1989 an Irish company called Intrepid developed one of the most
advanced secure phones. Called Milcode, the phone was the first to
implement Code Excited Linear Prediction (or CELP) which
dramatically improved voice quality and user operability over previous LPC (Linear Predictive Coding) and
LPC-10e versions.https://store.theartofservice.com/the-predictive-coding-toolkit.html
Log area ratio
1 'Log area ratios' ('LAR') can be used to represent reflection
coefficients (another form for Linear predictive coding|linear prediction
coefficients) for transmission over a channel. While not as efficient as line spectral pairs (LSPs), log area ratios
are much simpler to compute. Let r_k be the kth reflection coefficient of a
filter, the kth LAR is:https://store.theartofservice.com/the-predictive-coding-toolkit.html
Golomb coding - Applications
1 Several lossless audio data compression|audio codecs, such as Shorten (file format)|Shorten,[http://www.etree.org/shnutils/short
en/support/doc/shorten.txt man shorten] FLAC,[http://flac.sourceforge.net/document
ation_format_overview.html FLAC documentation: format overview] Apple
Lossless, and MPEG-4 ALS, use a Rice code after the Linear predictive coding|linear
prediction step (called adaptive FIR filter in Apple Lossless).
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Linear predictive coding
1 'Linear predictive coding' ('LPC') is a tool used mostly in audio signal
processing and speech processing for representing the spectral envelope of
a Digital data|digital signal (information theory)|signal of Speech
communication|speech in data compression|compressed form, using the information of a linear prediction|
linear predictive modelhttps://store.theartofservice.com/the-predictive-coding-toolkit.html
Linear predictive coding - Applications
1 Paul Lansky made the well-known computer music piece
notjustmoreidlechatter using linear predictive
coding.[http://www.music.princeton.edu/~paul/liner_notes/morethanidlech
atter.html]
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Release time -
1 'Analysis/resynthesis' is a form of synthesis that uses a series of
bandpass filters or Fourier transforms to analyze the harmonic content of a sound. The resulting analysis data is
then used in a second stage to resynthesize the sound using a band
of oscillators. The vocoder, linear predictive coding, and some forms of
speech synthesis are based on analysis/resynthesis.
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Codec2 - Overview
1 The LSP coefficients represent the Linear predictive coding|Linear
Predictive Coding (LPC) model in the frequency domain, and lend
themselves to
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G.728
1 The linear prediction is calculated backwards with a 50th order linear predictive coding
filter
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Lossless JPEG - Lossless mode of operation
1 Unlike the lossy mode which is based on the DCT, the lossless coding
process employs a simple predictive coding model called differential pulse
code modulation (DPCM)
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Harmonic Vector Excitation Coding - Linear Predictive Coding
1 HVXC uses Linear predictive coding (LPC) with block-wise adaptation every 20ms. The LPC parameters are transformed to Line spectral
pairs|Line spectral pair (LSP) coefficients, which are jointly quantized. The LPC residual signal is classified as either voiced or unvoiced. In the
case of voiced speech, the residual is coded in a parametric representation (operating as a
vocoder), while in the case of unvoiced speech, the residual waveform is quantized (thus
operating as hybrid speech codec).
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Audio Lossless Coding
1 The short-term predictor is similar to Free Lossless Audio Codec|FLAC in its
operation - it is a quantized Linear predictive coding|LPC predictor with
a losslessly coded residual using Golomb coding|Golomb Rice Coding
or Block Gilbert Moore Coding (BGMC)
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TI-99/4A - Features
1 The synthesizer used a variant of linear predictive coding and had a small in-built
vocabulary
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Adaptive Multi-Rate audio codec - Features
1 ** Linear predictive coding (LPC) is used to synthesize the speech from a
residual waveform. The LPC parameters are encoded as Line
spectral pairs (LSP).
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Paul Lansky - Biography
1 Following that came More Than Idle Chatter, the six compositions of
which focus on processings of the human voice using linear predictive
coding, granular synthesis, and plucked string synthesis; its three highlights are Granular synthesis|granular synth pieces called Idle
Chatter, Just_more_idle_chatter, and Notjustmoreidlechatter, which look at
the same thing from multiple perspectives
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FS-1015
1 The standard was finished 1984. The algorithm used is a linear predictive coding vocoder. The vocoder enables
understandable speech, but the quality is very unnatural and synthetic. File size is 20 times
smaller than MP3 - it is very small.
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System 16 - G80 specifications
1 *** Speech synthesis|Speech synthesizer: General Instrument
SP0256|General Instrument SP0250 (linear predictive coding)
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Audio timescale-pitch modification - Pitch scaling
1 A process that preserves the formants and character of a voice
involves analyzing the signal with a vocoder|channel vocoder or Linear predictive coding|LPC vocoder plus
any of several pitch detection algorithms and then resynthesizing it at a different fundamental frequency.
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MPEG-2 - Patents (U.S. only)
1 | 5291284 || 23 jul 1991 || 01 mar 1994 || 12 dec 1989 || 01 mar 2011 || Predictive coding and decoding with
error drift reduction || http://patft1.uspto.gov/netacgi/nph-
Parser?patentnumber=5291284 file+20: [2011, 7, 23] pct_file+20:
[2009, 12, 12] grant+17:[2011, 3, 1] || British Telecommunications plc
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MPEG-2 - Patents (U.S. only)
1 | 5317397 || 29 May 1992 || 31 May 1994 || 29 May 1992 || 29 May 2012
|| Predictive coding using spatial-temporal filtering and plural motion
vectors || http://patft1.uspto.gov/netacgi/nph-
Parser?patentnumber=5317397 file+20: [2012, 5, 29] grant+17:
[2011, 5, 31] || Toshiba
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MPEG-2 - Patents (U.S. only)
1 | 5103307 || 18 jan 1991 || 07 apr 1992 || 18 jan 1991 || 18 jan 2011 ||
Interframe predictive coding/decoding system for varying
interval between independent frames ||
http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=5103307 file+20: [2011, 1, 18] grant+17:
[2009, 4, 7] || JVC|Victor Companyhttps://store.theartofservice.com/the-predictive-coding-toolkit.html
Vocoder - Modern implementations
1 * LPC-10, Federal Information Processing Standard|FIPS Pub 137,
2400 bit/s, which uses linear predictive coding
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Echo 2
1 LPC (linear predictive coding) was the speech synthesis technology
used, which allowed applications to encode speech data in a compact form. The Echo II used the Texas
Instruments LPC Speech Chips|TMS 5220 LPC Speech Chip which was
popular in other speech synthesizers
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Texas Instruments LPC Speech Chips - Theory
1 Speech communication|Speech data is stored through pitch-excited linear
predictive coding (PE-LPC), where words are created by a lattice filter, selectably fed by
either an excitation Read-only memory|ROM (containing a glottal pulse waveform) or an LFSR (linear feedback shift register) noise
generator. Linear predictive coding achieves a vast reduction in data volume needed to
recreate intelligible speech data.
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Texas Instruments LPC Speech Chips - History
1 The TMC0280/TMS5100 was the first self-contained linear predictive coding|LPC speech synthesizer Integrated Circuit|IC ever made
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