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Fix LTP Scaling Parameter generation

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Was incorrectly not subframe aware
This commit is contained in:
Sean DuBois 2022-09-21 16:08:50 -04:00
parent 9886d0ca79
commit 42288fd1e3
2 changed files with 41 additions and 29 deletions
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63
internal/silk/decoder.go
View file

@ -1271,12 +1271,17 @@ func (d *Decoder) decodeLTPScalingParamater(signalType frameSignalType) (LTPscal
// from one of three codebooks.
//
// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.6.2
func (d *Decoder) decodeLTPFilterCoefficients(signalType frameSignalType) (bQ7 []int8) {
func (d *Decoder) decodeLTPFilterCoefficients(signalType frameSignalType) (bQ7 [][]int8) {
if signalType != frameSignalTypeVoiced {
return
}
bQ7 = make([]int8, 5)
bQ7 = [][]int8{
make([]int8, 5),
make([]int8, 5),
make([]int8, 5),
make([]int8, 5),
}
// This is signaled with an explicitly-coded "periodicity index". This
// immediately follows the subframe pitch lags, and is coded using the
@ -1287,30 +1292,32 @@ func (d *Decoder) decodeLTPFilterCoefficients(signalType frameSignalType) (bQ7 [
// coded using the PDF from Table 38 corresponding to the periodicity
// index. Tables 39 through 41 contain the corresponding filter taps as
// signed Q7 integers.
var filterIndiceIcdf []uint
switch periodicityIndex {
case 0:
filterIndiceIcdf = icdfLTPFilterIndex0
case 1:
filterIndiceIcdf = icdfLTPFilterIndex1
case 2:
filterIndiceIcdf = icdfLTPFilterIndex2
for i := 0; i < subframeCount; i++ {
var filterIndiceIcdf []uint
switch periodicityIndex {
case 0:
filterIndiceIcdf = icdfLTPFilterIndex0
case 1:
filterIndiceIcdf = icdfLTPFilterIndex1
case 2:
filterIndiceIcdf = icdfLTPFilterIndex2
}
filterIndex := d.rangeDecoder.DecodeSymbolWithICDF(filterIndiceIcdf)
var LTPFilterCodebook [][]int8
switch periodicityIndex {
case 0:
LTPFilterCodebook = codebookLTPFilterPeriodicityIndex0
case 1:
LTPFilterCodebook = codebookLTPFilterPeriodicityIndex1
case 2:
LTPFilterCodebook = codebookLTPFilterPeriodicityIndex2
}
copy(bQ7[i], LTPFilterCodebook[filterIndex])
}
filterIndex := d.rangeDecoder.DecodeSymbolWithICDF(filterIndiceIcdf)
var LTPFilterCodebook [][]int8
switch periodicityIndex {
case 0:
LTPFilterCodebook = codebookLTPFilterPeriodicityIndex0
case 1:
LTPFilterCodebook = codebookLTPFilterPeriodicityIndex1
case 2:
LTPFilterCodebook = codebookLTPFilterPeriodicityIndex2
}
copy(bQ7, LTPFilterCodebook[filterIndex])
return
}
@ -1334,7 +1341,7 @@ func (d *Decoder) samplesInSubframe(bandwidth Bandwidth) int {
func (d *Decoder) ltpSynthesis(
out []float32,
signalType frameSignalType,
bQ7 []int8,
bQ7 [][]int8,
pitchLags []int,
eQ23 []int32,
n, j, s, dLPC int,
@ -1480,7 +1487,7 @@ func (d *Decoder) ltpSynthesis(
if resValIndex < 0 || resValIndex >= len(res) {
resVal = 0
} else {
resVal = res[resValIndex] * (float32(bQ7[k]) / 128.0)
resVal = res[resValIndex] * (float32(bQ7[s][k]) / 128.0)
}
@ -1564,7 +1571,7 @@ func (d *Decoder) lpcSynthesis(out []float32, bandwidth Bandwidth, n, s, dLPC in
func (d *Decoder) silkFrameReconstruction(
signalType frameSignalType, bandwidth Bandwidth,
dLPC int,
bQ7 []int8,
bQ7 [][]int8,
pitchLags []int,
eQ23 []int32,
LTPscaleQ14 float32,

7
internal/silk/decoder_test.go
View file

@ -411,7 +411,12 @@ func TestDecodeLTPFilterCoefficients(t *testing.T) {
d := &Decoder{rangeDecoder: createRangeDecoder(silkFrame, 89, 253853952, 138203876)}
bQ7 := d.decodeLTPFilterCoefficients(frameSignalTypeVoiced)
if !reflect.DeepEqual(bQ7, []int8{1, 1, 8, 1, 1}) {
if !reflect.DeepEqual(bQ7, [][]int8{
{1, 1, 8, 1, 1},
{2, 0, 77, 11, 9},
{1, 1, 8, 1, 1},
{-1, 36, 64, 27, -6},
}) {
t.Fatal()
}
}