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Make more state available to LTP Synthesis

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Unimplemented but needed
This commit is contained in:
Sean DuBois 2022-09-16 22:32:17 -04:00
parent 56e47b2485
commit 0112ac2b3e
2 changed files with 42 additions and 39 deletions
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72
internal/silk/decoder.go
View file

@ -404,7 +404,7 @@ func (d *Decoder) normalizeLSFStabilization(nlsfQ15 []int16) {
// (in the same channel) and the current frame
//
// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.5.5
func (d *Decoder) normalizeLSFInterpolation(n2Q15 []int16) (n1Q15 []int16) {
func (d *Decoder) normalizeLSFInterpolation(n2Q15 []int16) (n1Q15 []int16, wQ2 int16) {
// Let n2_Q15[k] be the normalized LSF coefficients decoded by the
// procedure in Section 4.2.7.5, n0_Q15[k] be the LSF coefficients
// decoded for the prior frame, and w_Q2 be the interpolation factor.
@ -412,9 +412,9 @@ func (d *Decoder) normalizeLSFInterpolation(n2Q15 []int16) (n1Q15 []int16) {
// 20 ms frame, n1_Q15[k], are
//
// n1_Q15[k] = n0_Q15[k] + (w_Q2*(n2_Q15[k] - n0_Q15[k]) >> 2)
wQ2 := int16(d.rangeDecoder.DecodeSymbolWithICDF(icdfNormalizedLSFInterpolationIndex))
wQ2 = int16(d.rangeDecoder.DecodeSymbolWithICDF(icdfNormalizedLSFInterpolationIndex))
if wQ2 == 4 || !d.haveDecoded {
return n2Q15
return n2Q15, wQ2
}
n1Q15 = make([]int16, len(n2Q15))
@ -565,7 +565,7 @@ func (d *Decoder) decodeLinearCongruentialGeneratorSeed() uint32 {
// | WB | 20 ms | 20 |
// +-----------------+------------+------------------------+
//
// Table 44: Number of Shell Blocks Per SILK Frame
// Table 44: Number of Shell Blocks Per SILK Frame
//
// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8
func (d *Decoder) decodeShellblocks(nanoseconds int, bandwidth Bandwidth) (shellblocks int) {
@ -1326,7 +1326,7 @@ func (d *Decoder) samplesInSubframe(bandwidth Bandwidth) int {
}
// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.9.1
func (d *Decoder) ltpSynthesis(signalType frameSignalType, eQ23 []int32) (res []float64) {
func (d *Decoder) ltpSynthesis(signalType frameSignalType, eQ23 []int32, i int, LTPscaleQ14 float64, bandwidth Bandwidth, wQ2 int16) (res []float64) {
// For unvoiced frames (see Section 4.2.7.3), the LPC residual for i
// such that j <= i < (j + n) is simply a normalized copy of the
// excitation signal, i.e.,
@ -1412,39 +1412,39 @@ func (d *Decoder) lpcSynthesis(out []float64, bandwidth Bandwidth, currentSubfra
//
out[i] = clampFloat(-1.0, lpc[i], 1.0)
}
}
// Decode decodes many SILK subframes
// An overview of the decoder is given in Figure 14.
//
// +---------+ +------------+
// -->| Range |--->| Decode |---------------------------+
// 1 | Decoder | 2 | Parameters |----------+ 5 |
// +---------+ +------------+ 4 | |
// 3 | | |
// \/ \/ \/
// +------------+ +------------+ +------------+
// | Generate |-->| LTP |-->| LPC |
// | Excitation | | Synthesis | | Synthesis |
// +------------+ +------------+ +------------+
// ^ |
// | |
// +-------------------+----------------+
// | 6
// | +------------+ +-------------+
// +-->| Stereo |-->| Sample Rate |-->
// | Unmixing | 7 | Conversion | 8
// +------------+ +-------------+
// An overview of the decoder is given in Figure 14.
//
// 1: Range encoded bitstream
// 2: Coded parameters
// 3: Pulses, LSBs, and signs
// 4: Pitch lags, Long-Term Prediction (LTP) coefficients
// 5: Linear Predictive Coding (LPC) coefficients and gains
// 6: Decoded signal (mono or mid-side stereo)
// 7: Unmixed signal (mono or left-right stereo)
// 8: Resampled signal
// +---------+ +------------+
// -->| Range |--->| Decode |---------------------------+
// 1 | Decoder | 2 | Parameters |----------+ 5 |
// +---------+ +------------+ 4 | |
// 3 | | |
// \/ \/ \/
// +------------+ +------------+ +------------+
// | Generate |-->| LTP |-->| LPC |
// | Excitation | | Synthesis | | Synthesis |
// +------------+ +------------+ +------------+
// ^ |
// | |
// +-------------------+----------------+
// | 6
// | +------------+ +-------------+
// +-->| Stereo |-->| Sample Rate |-->
// | Unmixing | 7 | Conversion | 8
// +------------+ +-------------+
//
// 1: Range encoded bitstream
// 2: Coded parameters
// 3: Pulses, LSBs, and signs
// 4: Pitch lags, Long-Term Prediction (LTP) coefficients
// 5: Linear Predictive Coding (LPC) coefficients and gains
// 6: Decoded signal (mono or mid-side stereo)
// 7: Unmixed signal (mono or left-right stereo)
// 8: Resampled signal
//
// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.1
func (d *Decoder) Decode(in []byte, out []float64, isStereo bool, nanoseconds int, bandwidth Bandwidth) error {
@ -1483,7 +1483,7 @@ func (d *Decoder) Decode(in []byte, out []float64, isStereo bool, nanoseconds in
d.normalizeLSFStabilization(nlsfQ15)
// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.5.5
n1Q15 := d.normalizeLSFInterpolation(nlsfQ15)
n1Q15, wQ2 := d.normalizeLSFInterpolation(nlsfQ15)
// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.5.6
a32Q17 := d.convertNormalizedLSFsToLPCCoefficients(n1Q15, bandwidth)
@ -1501,7 +1501,7 @@ func (d *Decoder) Decode(in []byte, out []float64, isStereo bool, nanoseconds in
d.decodeLTPFilterCoefficients(signalType)
// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.6.3
_ = d.decodeLTPScalingParamater(signalType)
LTPscaleQ14 := d.decodeLTPScalingParamater(signalType)
// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.7
lcgSeed := d.decodeLinearCongruentialGeneratorSeed()
@ -1520,7 +1520,7 @@ func (d *Decoder) Decode(in []byte, out []float64, isStereo bool, nanoseconds in
for i := 0; i < subframeCount; i++ {
// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.9.1
res := d.ltpSynthesis(signalType, eQ23)
res := d.ltpSynthesis(signalType, eQ23, subframeCount, LTPscaleQ14, bandwidth, wQ2)
//https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.9.2
d.lpcSynthesis(out[subframeSize*i:], bandwidth, i, dLPC, aQ12, res, gainQ16)

9
internal/silk/decoder_test.go
View file

@ -105,12 +105,13 @@ func TestNormalizeLineSpectralFrequencyCoefficients(t *testing.T) {
func TestNormalizeLSFInterpolation(t *testing.T) {
t.Run("wQ2 == 4", func(t *testing.T) {
d := &Decoder{rangeDecoder: createRangeDecoder(testSilkFrame(), 55, 493249168, 174371199)}
n2Q15 := []int16{
expectedN1Q15 := []int16{
2132, 3584, 5504, 7424, 9472, 11392, 13440, 15360, 17280,
19200, 21120, 23040, 25088, 27008, 28928, 30848,
}
if !reflect.DeepEqual(d.normalizeLSFInterpolation(n2Q15), n2Q15) {
actualN1Q15, _ := d.normalizeLSFInterpolation(expectedN1Q15)
if !reflect.DeepEqual(actualN1Q15, expectedN1Q15) {
t.Fatal()
}
})
@ -130,7 +131,9 @@ func TestNormalizeLSFInterpolation(t *testing.T) {
17622, 19433, 21888, 24000, 26048, 28224, 30240,
}
if !reflect.DeepEqual(d.normalizeLSFInterpolation(n2Q15), expectedN1Q15) {
actualN2Q15, _ := d.normalizeLSFInterpolation(n2Q15)
if !reflect.DeepEqual(actualN2Q15, expectedN1Q15) {
t.Fatal()
}
})