gr-gsm/lib/decoding/openbts/AmrCoder.h

942 lines
28 KiB
C++

/*
* Copyright 2013, 2014 Range Networks, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* This use of this software may be subject to additional restrictions.
* See the LEGAL file in the main directory for details.
*/
#ifndef _AMRCODER_H_
#define _AMRCODER_H_
#include <stdint.h>
#include "BitVector.h"
#include "Viterbi.h"
/**
Class to represent recursive systematic convolutional coders/decoders of rate 1/2, memory length 4.
*/
class ViterbiTCH_AFS12_2 : public ViterbiBase {
private:
/**name Lots of precomputed elements so the compiler can optimize like hell. */
//@{
/**@name Core values. */
//@{
static const unsigned mIRate = 2; ///< reciprocal of rate
static const unsigned mOrder = 4; ///< memory length of generators
//@}
/**@name Derived values. */
//@{
static const unsigned mIStates = 0x01 << mOrder; ///< number of states, number of survivors
static const uint32_t mSMask = mIStates-1; ///< survivor mask
static const uint32_t mCMask = (mSMask<<1) | 0x01; ///< candidate mask
static const uint32_t mOMask = (0x01<<mIRate)-1; ///< ouput mask, all iRate low bits set
static const unsigned mNumCands = mIStates*2; ///< number of candidates to generate during branching
static const unsigned mDeferral = 6*mOrder; ///< deferral to be used
//@}
//@}
/** Precomputed tables. */
//@{
uint32_t mCoeffs[mIRate]; ///< output polynomial for each generator
uint32_t mCoeffsFB[mIRate]; ///< feedback polynomial for each generator
uint32_t mStateTable[mIRate][2*mIStates]; ///< precomputed generator output tables
uint32_t mGeneratorTable[2*mIStates]; ///< precomputed coder output table
//@}
public:
/**
A candidate sequence in a Viterbi decoder.
The 32-bit state register can support a deferral of 6 with a 4th-order coder.
*/
typedef struct candStruct {
uint32_t iState; ///< encoder input associated with this candidate
uint32_t oState; ///< encoder output associated with this candidate
char rState[mIRate];///< real states of encoders associated with this candidate
float cost; ///< cost (metric value), float to support soft inputs
} vCand;
/** Clear a structure. */
void vitClear(vCand& v)
{
v.iState=0;
v.oState=0;
v.cost=0;
for (unsigned i = 0; i < mIRate; i++) v.rState[i] = 0;
}
private:
/**@name Survivors and candidates. */
//@{
vCand mSurvivors[mIStates]; ///< current survivor pool
vCand mCandidates[2*mIStates]; ///< current candidate pool
//@}
public:
unsigned iRate() const { return mIRate; }
uint32_t cMask() const { return mCMask; }
uint32_t stateTable(unsigned g, unsigned i) const { return mStateTable[g][i]; }
unsigned deferral() const { return mDeferral; }
ViterbiTCH_AFS12_2();
/** Set all cost metrics to zero. */
void initializeStates();
/**
Full cycle of the Viterbi algorithm: branch, metrics, prune, select.
@return reference to minimum-cost candidate.
*/
const vCand& step(uint32_t inSample, const float *probs, const float *iprobs);
private:
/** Branch survivors into new candidates. */
void branchCandidates();
/** Compute cost metrics for soft-inputs. */
void getSoftCostMetrics(uint32_t inSample, const float *probs, const float *iprobs);
/** Select survivors from the candidate set. */
void pruneCandidates();
/** Find the minimum cost survivor. */
const vCand& minCost() const;
/**
Precompute the state tables.
@param g Generator index 0..((1/rate)-1)
*/
void computeStateTables(unsigned g);
/**
Precompute the generator outputs.
mCoeffs must be defined first.
*/
void computeGeneratorTable();
void encode(const BitVector &in, BitVector& target) const;
void decode(const SoftVector &in, BitVector& target);
};
/**
Class to represent recursive systematic convolutional coders/decoders of rate 1/3, memory length 4.
*/
class ViterbiTCH_AFS10_2 : public ViterbiBase {
private:
/**name Lots of precomputed elements so the compiler can optimize like hell. */
//@{
/**@name Core values. */
//@{
static const unsigned mIRate = 3; ///< reciprocal of rate
static const unsigned mOrder = 4; ///< memory length of generators
//@}
/**@name Derived values. */
//@{
static const unsigned mIStates = 0x01 << mOrder; ///< number of states, number of survivors
static const uint32_t mSMask = mIStates-1; ///< survivor mask
static const uint32_t mCMask = (mSMask<<1) | 0x01; ///< candidate mask
static const uint32_t mOMask = (0x01<<mIRate)-1; ///< ouput mask, all iRate low bits set
static const unsigned mNumCands = mIStates*2; ///< number of candidates to generate during branching
static const unsigned mDeferral = 6*mOrder; ///< deferral to be used
//@}
//@}
/** Precomputed tables. */
//@{
uint32_t mCoeffs[mIRate]; ///< output polynomial for each generator
uint32_t mCoeffsFB[mIRate]; ///< feedback polynomial for each generator
uint32_t mStateTable[mIRate][2*mIStates]; ///< precomputed generator output tables
uint32_t mGeneratorTable[2*mIStates]; ///< precomputed coder output table
//@}
public:
/**
A candidate sequence in a Viterbi decoder.
The 32-bit state register can support a deferral of 6 with a 4th-order coder.
*/
typedef struct candStruct {
uint32_t iState; ///< encoder input associated with this candidate
uint32_t oState; ///< encoder output associated with this candidate
char rState[mIRate];///< real states of encoders associated with this candidate
float cost; ///< cost (metric value), float to support soft inputs
} vCand;
/** Clear a structure. */
void vitClear(vCand& v)
{
v.iState=0;
v.oState=0;
v.cost=0;
for (unsigned i = 0; i < mIRate; i++) v.rState[i] = 0;
}
private:
/**@name Survivors and candidates. */
//@{
vCand mSurvivors[mIStates]; ///< current survivor pool
vCand mCandidates[2*mIStates]; ///< current candidate pool
//@}
public:
unsigned iRate() const { return mIRate; }
uint32_t cMask() const { return mCMask; }
uint32_t stateTable(unsigned g, unsigned i) const { return mStateTable[g][i]; }
unsigned deferral() const { return mDeferral; }
ViterbiTCH_AFS10_2();
/** Set all cost metrics to zero. */
void initializeStates();
/**
Full cycle of the Viterbi algorithm: branch, metrics, prune, select.
@return reference to minimum-cost candidate.
*/
const vCand& step(uint32_t inSample, const float *probs, const float *iprobs);
private:
/** Branch survivors into new candidates. */
void branchCandidates();
/** Compute cost metrics for soft-inputs. */
void getSoftCostMetrics(uint32_t inSample, const float *probs, const float *iprobs);
/** Select survivors from the candidate set. */
void pruneCandidates();
/** Find the minimum cost survivor. */
const vCand& minCost() const;
/**
Precompute the state tables.
@param g Generator index 0..((1/rate)-1)
*/
void computeStateTables(unsigned g);
/**
Precompute the generator outputs.
mCoeffs must be defined first.
*/
void computeGeneratorTable();
void encode(const BitVector &in, BitVector& target) const;
void decode(const SoftVector &in, BitVector& target);
};
/**
Class to represent recursive systematic convolutional coders/decoders of rate 1/3, memory length 6.
*/
class ViterbiTCH_AFS7_95 : public ViterbiBase {
private:
/**name Lots of precomputed elements so the compiler can optimize like hell. */
//@{
/**@name Core values. */
//@{
static const unsigned mIRate = 3; ///< reciprocal of rate
static const unsigned mOrder = 6; ///< memory length of generators
//@}
/**@name Derived values. */
//@{
static const unsigned mIStates = 0x01 << mOrder; ///< number of states, number of survivors
static const uint32_t mSMask = mIStates-1; ///< survivor mask
static const uint32_t mCMask = (mSMask<<1) | 0x01; ///< candidate mask
static const uint32_t mOMask = (0x01<<mIRate)-1; ///< ouput mask, all iRate low bits set
static const unsigned mNumCands = mIStates*2; ///< number of candidates to generate during branching
static const unsigned mDeferral = 5*mOrder; ///< deferral to be used
//@}
//@}
/** Precomputed tables. */
//@{
uint32_t mCoeffs[mIRate]; ///< output polynomial for each generator
uint32_t mCoeffsFB[mIRate]; ///< feedback polynomial for each generator
uint32_t mStateTable[mIRate][2*mIStates]; ///< precomputed generator output tables
uint32_t mGeneratorTable[2*mIStates]; ///< precomputed coder output table
//@}
public:
/**
A candidate sequence in a Viterbi decoder.
The 32-bit state register can support a deferral of 5*order with a 6th-order coder.
*/
typedef struct candStruct {
uint32_t iState; ///< encoder input associated with this candidate
uint32_t oState; ///< encoder output associated with this candidate
char rState[mIRate];///< real states of encoders associated with this candidate
float cost; ///< cost (metric value), float to support soft inputs
} vCand;
/** Clear a structure. */
void vitClear(vCand& v)
{
v.iState=0;
v.oState=0;
v.cost=0;
for (unsigned i = 0; i < mIRate; i++) v.rState[i] = 0;
}
private:
/**@name Survivors and candidates. */
//@{
vCand mSurvivors[mIStates]; ///< current survivor pool
vCand mCandidates[2*mIStates]; ///< current candidate pool
//@}
public:
unsigned iRate() const { return mIRate; }
uint32_t cMask() const { return mCMask; }
uint32_t stateTable(unsigned g, unsigned i) const { return mStateTable[g][i]; }
unsigned deferral() const { return mDeferral; }
ViterbiTCH_AFS7_95();
/** Set all cost metrics to zero. */
void initializeStates();
/**
Full cycle of the Viterbi algorithm: branch, metrics, prune, select.
@return reference to minimum-cost candidate.
*/
const vCand& step(uint32_t inSample, const float *probs, const float *iprobs);
private:
/** Branch survivors into new candidates. */
void branchCandidates();
/** Compute cost metrics for soft-inputs. */
void getSoftCostMetrics(uint32_t inSample, const float *probs, const float *iprobs);
/** Select survivors from the candidate set. */
void pruneCandidates();
/** Find the minimum cost survivor. */
const vCand& minCost() const;
/**
Precompute the state tables.
@param g Generator index 0..((1/rate)-1)
*/
void computeStateTables(unsigned g);
/**
Precompute the generator outputs.
mCoeffs must be defined first.
*/
void computeGeneratorTable();
void encode(const BitVector &in, BitVector& target) const;
void decode(const SoftVector &in, BitVector& target);
};
/**
Class to represent recursive systematic convolutional coders/decoders of rate 1/3, memory length 4.
*/
class ViterbiTCH_AFS7_4 : public ViterbiBase {
private:
/**name Lots of precomputed elements so the compiler can optimize like hell. */
//@{
/**@name Core values. */
//@{
static const unsigned mIRate = 3; ///< reciprocal of rate
static const unsigned mOrder = 4; ///< memory length of generators
//@}
/**@name Derived values. */
//@{
static const unsigned mIStates = 0x01 << mOrder; ///< number of states, number of survivors
static const uint32_t mSMask = mIStates-1; ///< survivor mask
static const uint32_t mCMask = (mSMask<<1) | 0x01; ///< candidate mask
static const uint32_t mOMask = (0x01<<mIRate)-1; ///< ouput mask, all iRate low bits set
static const unsigned mNumCands = mIStates*2; ///< number of candidates to generate during branching
static const unsigned mDeferral = 6*mOrder; ///< deferral to be used
//@}
//@}
/** Precomputed tables. */
//@{
uint32_t mCoeffs[mIRate]; ///< output polynomial for each generator
uint32_t mCoeffsFB[mIRate]; ///< feedback polynomial for each generator
uint32_t mStateTable[mIRate][2*mIStates]; ///< precomputed generator output tables
uint32_t mGeneratorTable[2*mIStates]; ///< precomputed coder output table
//@}
public:
/**
A candidate sequence in a Viterbi decoder.
The 32-bit state register can support a deferral of 6 with a 4th-order coder.
*/
typedef struct candStruct {
uint32_t iState; ///< encoder input associated with this candidate
uint32_t oState; ///< encoder output associated with this candidate
char rState[mIRate];///< real states of encoders associated with this candidate
float cost; ///< cost (metric value), float to support soft inputs
} vCand;
/** Clear a structure. */
void vitClear(vCand& v)
{
v.iState=0;
v.oState=0;
v.cost=0;
for (unsigned i = 0; i < mIRate; i++) v.rState[i] = 0;
}
private:
/**@name Survivors and candidates. */
//@{
vCand mSurvivors[mIStates]; ///< current survivor pool
vCand mCandidates[2*mIStates]; ///< current candidate pool
//@}
public:
unsigned iRate() const { return mIRate; }
uint32_t cMask() const { return mCMask; }
uint32_t stateTable(unsigned g, unsigned i) const { return mStateTable[g][i]; }
unsigned deferral() const { return mDeferral; }
ViterbiTCH_AFS7_4();
/** Set all cost metrics to zero. */
void initializeStates();
/**
Full cycle of the Viterbi algorithm: branch, metrics, prune, select.
@return reference to minimum-cost candidate.
*/
const vCand& step(uint32_t inSample, const float *probs, const float *iprobs);
private:
/** Branch survivors into new candidates. */
void branchCandidates();
/** Compute cost metrics for soft-inputs. */
void getSoftCostMetrics(uint32_t inSample, const float *probs, const float *iprobs);
/** Select survivors from the candidate set. */
void pruneCandidates();
/** Find the minimum cost survivor. */
const vCand& minCost() const;
/**
Precompute the state tables.
@param g Generator index 0..((1/rate)-1)
*/
void computeStateTables(unsigned g);
/**
Precompute the generator outputs.
mCoeffs must be defined first.
*/
void computeGeneratorTable();
void encode(const BitVector &in, BitVector& target) const;
void decode(const SoftVector &in, BitVector& target);
};
/**
Class to represent recursive systematic convolutional coders/decoders of rate 1/4, memory length 4.
*/
class ViterbiTCH_AFS6_7 : public ViterbiBase {
private:
/**name Lots of precomputed elements so the compiler can optimize like hell. */
//@{
/**@name Core values. */
//@{
static const unsigned mIRate = 4; ///< reciprocal of rate
static const unsigned mOrder = 4; ///< memory length of generators
//@}
/**@name Derived values. */
//@{
static const unsigned mIStates = 0x01 << mOrder; ///< number of states, number of survivors
static const uint32_t mSMask = mIStates-1; ///< survivor mask
static const uint32_t mCMask = (mSMask<<1) | 0x01; ///< candidate mask
static const uint32_t mOMask = (0x01<<mIRate)-1; ///< ouput mask, all iRate low bits set
static const unsigned mNumCands = mIStates*2; ///< number of candidates to generate during branching
static const unsigned mDeferral = 6*mOrder; ///< deferral to be used
//@}
//@}
/** Precomputed tables. */
//@{
uint32_t mCoeffs[mIRate]; ///< output polynomial for each generator
uint32_t mCoeffsFB[mIRate]; ///< feedback polynomial for each generator
uint32_t mStateTable[mIRate][2*mIStates]; ///< precomputed generator output tables
uint32_t mGeneratorTable[2*mIStates]; ///< precomputed coder output table
//@}
public:
/**
A candidate sequence in a Viterbi decoder.
The 32-bit state register can support a deferral of 6 with a 4th-order coder.
*/
typedef struct candStruct {
uint32_t iState; ///< encoder input associated with this candidate
uint32_t oState; ///< encoder output associated with this candidate
char rState[mIRate];///< real states of encoders associated with this candidate
float cost; ///< cost (metric value), float to support soft inputs
} vCand;
/** Clear a structure. */
void vitClear(vCand& v)
{
v.iState=0;
v.oState=0;
v.cost=0;
for (unsigned i = 0; i < mIRate; i++) v.rState[i] = 0;
}
private:
/**@name Survivors and candidates. */
//@{
vCand mSurvivors[mIStates]; ///< current survivor pool
vCand mCandidates[2*mIStates]; ///< current candidate pool
//@}
public:
unsigned iRate() const { return mIRate; }
uint32_t cMask() const { return mCMask; }
uint32_t stateTable(unsigned g, unsigned i) const { return mStateTable[g][i]; }
unsigned deferral() const { return mDeferral; }
ViterbiTCH_AFS6_7();
/** Set all cost metrics to zero. */
void initializeStates();
/**
Full cycle of the Viterbi algorithm: branch, metrics, prune, select.
@return reference to minimum-cost candidate.
*/
const vCand& step(uint32_t inSample, const float *probs, const float *iprobs);
private:
/** Branch survivors into new candidates. */
void branchCandidates();
/** Compute cost metrics for soft-inputs. */
void getSoftCostMetrics(uint32_t inSample, const float *probs, const float *iprobs);
/** Select survivors from the candidate set. */
void pruneCandidates();
/** Find the minimum cost survivor. */
const vCand& minCost() const;
/**
Precompute the state tables.
@param g Generator index 0..((1/rate)-1)
*/
void computeStateTables(unsigned g);
/**
Precompute the generator outputs.
mCoeffs must be defined first.
*/
void computeGeneratorTable();
void encode(const BitVector &in, BitVector& target) const;
void decode(const SoftVector &in, BitVector& target);
};
/**
Class to represent recursive systematic convolutional coders/decoders of rate 1/4, memory length 6.
*/
class ViterbiTCH_AFS5_9 : public ViterbiBase {
private:
/**name Lots of precomputed elements so the compiler can optimize like hell. */
//@{
/**@name Core values. */
//@{
static const unsigned mIRate = 4; ///< reciprocal of rate
static const unsigned mOrder = 6; ///< memory length of generators
//@}
/**@name Derived values. */
//@{
static const unsigned mIStates = 0x01 << mOrder; ///< number of states, number of survivors
static const uint32_t mSMask = mIStates-1; ///< survivor mask
static const uint32_t mCMask = (mSMask<<1) | 0x01; ///< candidate mask
static const uint32_t mOMask = (0x01<<mIRate)-1; ///< ouput mask, all iRate low bits set
static const unsigned mNumCands = mIStates*2; ///< number of candidates to generate during branching
static const unsigned mDeferral = 5*mOrder; ///< deferral to be used
//@}
//@}
/** Precomputed tables. */
//@{
uint32_t mCoeffs[mIRate]; ///< output polynomial for each generator
uint32_t mCoeffsFB[mIRate]; ///< feedback polynomial for each generator
uint32_t mStateTable[mIRate][2*mIStates]; ///< precomputed generator output tables
uint32_t mGeneratorTable[2*mIStates]; ///< precomputed coder output table
//@}
public:
/**
A candidate sequence in a Viterbi decoder.
The 32-bit state register can support a deferral of 5*order with a 6th-order coder.
*/
typedef struct candStruct {
uint32_t iState; ///< encoder input associated with this candidate
uint32_t oState; ///< encoder output associated with this candidate
char rState[mIRate];///< real states of encoders associated with this candidate
float cost; ///< cost (metric value), float to support soft inputs
} vCand;
/** Clear a structure. */
void vitClear(vCand& v)
{
v.iState=0;
v.oState=0;
v.cost=0;
for (unsigned i = 0; i < mIRate; i++) v.rState[i] = 0;
}
private:
/**@name Survivors and candidates. */
//@{
vCand mSurvivors[mIStates]; ///< current survivor pool
vCand mCandidates[2*mIStates]; ///< current candidate pool
//@}
public:
unsigned iRate() const { return mIRate; }
uint32_t cMask() const { return mCMask; }
uint32_t stateTable(unsigned g, unsigned i) const { return mStateTable[g][i]; }
unsigned deferral() const { return mDeferral; }
ViterbiTCH_AFS5_9();
/** Set all cost metrics to zero. */
void initializeStates();
/**
Full cycle of the Viterbi algorithm: branch, metrics, prune, select.
@return reference to minimum-cost candidate.
*/
const vCand& step(uint32_t inSample, const float *probs, const float *iprobs);
private:
/** Branch survivors into new candidates. */
void branchCandidates();
/** Compute cost metrics for soft-inputs. */
void getSoftCostMetrics(uint32_t inSample, const float *probs, const float *iprobs);
/** Select survivors from the candidate set. */
void pruneCandidates();
/** Find the minimum cost survivor. */
const vCand& minCost() const;
/**
Precompute the state tables.
@param g Generator index 0..((1/rate)-1)
*/
void computeStateTables(unsigned g);
/**
Precompute the generator outputs.
mCoeffs must be defined first.
*/
void computeGeneratorTable();
void encode(const BitVector &in, BitVector& target) const;
void decode(const SoftVector &in, BitVector& target);
};
/**
Class to represent recursive systematic convolutional coders/decoders of rate 1/5, memory length 4.
*/
class ViterbiTCH_AFS5_15 : public ViterbiBase {
private:
/**name Lots of precomputed elements so the compiler can optimize like hell. */
//@{
/**@name Core values. */
//@{
static const unsigned mIRate = 5; ///< reciprocal of rate
static const unsigned mOrder = 4; ///< memory length of generators
//@}
/**@name Derived values. */
//@{
static const unsigned mIStates = 0x01 << mOrder; ///< number of states, number of survivors
static const uint32_t mSMask = mIStates-1; ///< survivor mask
static const uint32_t mCMask = (mSMask<<1) | 0x01; ///< candidate mask
static const uint32_t mOMask = (0x01<<mIRate)-1; ///< ouput mask, all iRate low bits set
static const unsigned mNumCands = mIStates*2; ///< number of candidates to generate during branching
static const unsigned mDeferral = 6*mOrder; ///< deferral to be used
//@}
//@}
/** Precomputed tables. */
//@{
uint32_t mCoeffs[mIRate]; ///< output polynomial for each generator
uint32_t mCoeffsFB[mIRate]; ///< feedback polynomial for each generator
uint32_t mStateTable[mIRate][2*mIStates]; ///< precomputed generator output tables
uint32_t mGeneratorTable[2*mIStates]; ///< precomputed coder output table
//@}
public:
/**
A candidate sequence in a Viterbi decoder.
The 32-bit state register can support a deferral of 6 with a 4th-order coder.
*/
typedef struct candStruct {
uint32_t iState; ///< encoder input associated with this candidate
uint32_t oState; ///< encoder output associated with this candidate
char rState[mIRate];///< real states of encoders associated with this candidate
float cost; ///< cost (metric value), float to support soft inputs
} vCand;
/** Clear a structure. */
void vitClear(vCand& v)
{
v.iState=0;
v.oState=0;
v.cost=0;
for (unsigned i = 0; i < mIRate; i++) v.rState[i] = 0;
}
private:
/**@name Survivors and candidates. */
//@{
vCand mSurvivors[mIStates]; ///< current survivor pool
vCand mCandidates[2*mIStates]; ///< current candidate pool
//@}
public:
unsigned iRate() const { return mIRate; }
uint32_t cMask() const { return mCMask; }
uint32_t stateTable(unsigned g, unsigned i) const { return mStateTable[g][i]; }
unsigned deferral() const { return mDeferral; }
ViterbiTCH_AFS5_15();
/** Set all cost metrics to zero. */
void initializeStates();
/**
Full cycle of the Viterbi algorithm: branch, metrics, prune, select.
@return reference to minimum-cost candidate.
*/
const vCand& step(uint32_t inSample, const float *probs, const float *iprobs);
private:
/** Branch survivors into new candidates. */
void branchCandidates();
/** Compute cost metrics for soft-inputs. */
void getSoftCostMetrics(uint32_t inSample, const float *probs, const float *iprobs);
/** Select survivors from the candidate set. */
void pruneCandidates();
/** Find the minimum cost survivor. */
const vCand& minCost() const;
/**
Precompute the state tables.
@param g Generator index 0..((1/rate)-1)
*/
void computeStateTables(unsigned g);
/**
Precompute the generator outputs.
mCoeffs must be defined first.
*/
void computeGeneratorTable();
void encode(const BitVector &in, BitVector& target) const;
void decode(const SoftVector &in, BitVector& target);
};
/**
Class to represent recursive systematic convolutional coders/decoders of rate 1/5, memory length 6.
*/
class ViterbiTCH_AFS4_75 : public ViterbiBase {
private:
/**name Lots of precomputed elements so the compiler can optimize like hell. */
//@{
/**@name Core values. */
//@{
static const unsigned mIRate = 5; ///< reciprocal of rate
static const unsigned mOrder = 6; ///< memory length of generators
//@}
/**@name Derived values. */
//@{
static const unsigned mIStates = 0x01 << mOrder; ///< number of states, number of survivors
static const uint32_t mSMask = mIStates-1; ///< survivor mask
static const uint32_t mCMask = (mSMask<<1) | 0x01; ///< candidate mask
static const uint32_t mOMask = (0x01<<mIRate)-1; ///< ouput mask, all iRate low bits set
static const unsigned mNumCands = mIStates*2; ///< number of candidates to generate during branching
static const unsigned mDeferral = 5*mOrder; ///< deferral to be used
//@}
//@}
/** Precomputed tables. */
//@{
uint32_t mCoeffs[mIRate]; ///< output polynomial for each generator
uint32_t mCoeffsFB[mIRate]; ///< feedback polynomial for each generator
uint32_t mStateTable[mIRate][2*mIStates]; ///< precomputed generator output tables
uint32_t mGeneratorTable[2*mIStates]; ///< precomputed coder output table
//@}
public:
/**
A candidate sequence in a Viterbi decoder.
The 32-bit state register can support a deferral of 5*order with a 6th-order coder.
*/
typedef struct candStruct {
uint32_t iState; ///< encoder input associated with this candidate
uint32_t oState; ///< encoder output associated with this candidate
char rState[mIRate];///< real states of encoders associated with this candidate
float cost; ///< cost (metric value), float to support soft inputs
} vCand;
/** Clear a structure. */
void vitClear(vCand& v)
{
v.iState=0;
v.oState=0;
v.cost=0;
for (unsigned i = 0; i < mIRate; i++) v.rState[i] = 0;
}
private:
/**@name Survivors and candidates. */
//@{
vCand mSurvivors[mIStates]; ///< current survivor pool
vCand mCandidates[2*mIStates]; ///< current candidate pool
//@}
public:
unsigned iRate() const { return mIRate; }
uint32_t cMask() const { return mCMask; }
uint32_t stateTable(unsigned g, unsigned i) const { return mStateTable[g][i]; }
unsigned deferral() const { return mDeferral; }
ViterbiTCH_AFS4_75();
/** Set all cost metrics to zero. */
void initializeStates();
/**
Full cycle of the Viterbi algorithm: branch, metrics, prune, select.
@return reference to minimum-cost candidate.
*/
const vCand& step(uint32_t inSample, const float *probs, const float *iprobs);
private:
/** Branch survivors into new candidates. */
void branchCandidates();
/** Compute cost metrics for soft-inputs. */
void getSoftCostMetrics(uint32_t inSample, const float *probs, const float *iprobs);
/** Select survivors from the candidate set. */
void pruneCandidates();
/** Find the minimum cost survivor. */
const vCand& minCost() const;
/**
Precompute the state tables.
@param g Generator index 0..((1/rate)-1)
*/
void computeStateTables(unsigned g);
/**
Precompute the generator outputs.
mCoeffs must be defined first.
*/
void computeGeneratorTable();
void encode(const BitVector &in, BitVector& target) const;
void decode(const SoftVector &in, BitVector& target);
};
#endif