Finish normalizeLSFInterpolation
Before we only handled when wQ2 == 4
This commit is contained in:
Sean DuBois
parent
496497d1f7
commit
e005fba189
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@ -15,8 +15,13 @@ type Decoder struct {
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// Is the previous frame a voiced frame?
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isPreviousFrameVoiced bool
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previousLogGain uint32
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// n0Q15 are the LSF coefficients decoded for the prior frame
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// see normalizeLSFInterpolation
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n0Q15 []int16
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// TODO, should have dedicated frame state
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logGain uint32
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subframeState [4]struct {
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}
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}
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@ -130,7 +135,7 @@ func (d *Decoder) decodeSubframeQuantizations(signalType frameSignalType) (gainQ
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// current gain is limited as follows:
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// log_gain = max(gain_index, previous_log_gain - 16)
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if d.haveDecoded {
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logGain = maxUint32(gainIndex, d.logGain-16)
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logGain = maxUint32(gainIndex, d.previousLogGain-16)
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} else {
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logGain = gainIndex
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}
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@ -144,10 +149,10 @@ func (d *Decoder) decodeSubframeQuantizations(signalType frameSignalType) (gainQ
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// The following formula translates this index into a quantization gain
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// for the current subframe using the gain from the previous subframe:
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// log_gain = clamp(0, max(2*delta_gain_index - 16, previous_log_gain + delta_gain_index - 4), 63)
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logGain = uint32(clamp(0, maxInt32(2*int32(deltaGainIndex)-16, int32(d.logGain+deltaGainIndex)-4), 63))
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logGain = uint32(clamp(0, maxInt32(2*int32(deltaGainIndex)-16, int32(d.previousLogGain+deltaGainIndex)-4), 63))
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}
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d.logGain = logGain
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d.previousLogGain = logGain
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// silk_gains_dequant() (gain_quant.c) dequantizes log_gain for the k'th
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// subframe and converts it into a linear Q16 scale factor via
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@ -397,7 +402,7 @@ func (d *Decoder) normalizeLSFStabilization(nlsfQ15 []int16) {
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// (in the same channel) and the current frame
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.5.5
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func (d *Decoder) normalizeLSFInterpolation(nlsfQ15 []int16) (n1Q15 []int16, err error) {
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func (d *Decoder) normalizeLSFInterpolation(n2Q15 []int16) (n1Q15 []int16) {
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// Let n2_Q15[k] be the normalized LSF coefficients decoded by the
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// procedure in Section 4.2.7.5, n0_Q15[k] be the LSF coefficients
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// decoded for the prior frame, and w_Q2 be the interpolation factor.
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@ -405,14 +410,17 @@ func (d *Decoder) normalizeLSFInterpolation(nlsfQ15 []int16) (n1Q15 []int16, err
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// 20 ms frame, n1_Q15[k], are
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//
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// n1_Q15[k] = n0_Q15[k] + (w_Q2*(n2_Q15[k] - n0_Q15[k]) >> 2)
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if wQ2 := d.rangeDecoder.DecodeSymbolWithICDF(icdfNormalizedLSFInterpolationIndex); wQ2 != 4 {
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return nil, errUnsupportedLSFInterpolation
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wQ2 := int16(d.rangeDecoder.DecodeSymbolWithICDF(icdfNormalizedLSFInterpolationIndex))
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if wQ2 == 4 || !d.haveDecoded {
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return n2Q15
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}
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// TODO
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n1Q15 = nlsfQ15
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n1Q15 = make([]int16, len(n2Q15))
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for k := range n1Q15 {
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n1Q15[k] = d.n0Q15[k] + (wQ2 * (n2Q15[k] - d.n0Q15[k]) >> 2)
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}
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return n1Q15, nil
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return
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}
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func (d *Decoder) convertNormalizedLSFsToLPCCoefficients(n1Q15 []int16, bandwidth Bandwidth) (a32Q17 []int32) {
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@ -1272,10 +1280,7 @@ func (d *Decoder) Decode(in []byte, out []float64, isStereo bool, nanoseconds in
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d.normalizeLSFStabilization(nlsfQ15)
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.5.5
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n1Q15, err := d.normalizeLSFInterpolation(nlsfQ15)
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if err != nil {
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return err
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}
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n1Q15 := d.normalizeLSFInterpolation(nlsfQ15)
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.5.6
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a32Q17 := d.convertNormalizedLSFsToLPCCoefficients(n1Q15, bandwidth)
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@ -1297,7 +1302,7 @@ func (d *Decoder) Decode(in []byte, out []float64, isStereo bool, nanoseconds in
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}
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// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.6.3
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_, err = d.decodeLTPScalingParamater(signalType)
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_, err := d.decodeLTPScalingParamater(signalType)
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if err != nil {
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return err
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}
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@ -1323,6 +1328,15 @@ func (d *Decoder) Decode(in []byte, out []float64, isStereo bool, nanoseconds in
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//https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.9.2
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d.lpcSynthesis(out, bandwidth, dLPC, aQ12, res, gainQ16)
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// n0Q15 is the LSF coefficients decoded for the prior frame
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// see normalizeLSFInterpolation.
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if len(d.n0Q15) != len(nlsfQ15) {
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d.n0Q15 = make([]int16, len(nlsfQ15))
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}
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copy(d.n0Q15, nlsfQ15)
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d.isPreviousFrameVoiced = signalType == frameSignalTypeVoiced
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d.haveDecoded = true
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return nil
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}
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@ -58,14 +58,7 @@ func TestDecodeSubframeQuantizations(t *testing.T) {
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d := &Decoder{rangeDecoder: createRangeDecoder(testSilkFrame(), 31, 482344960, 437100388)}
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gainQ16 := d.decodeSubframeQuantizations(frameSignalTypeInactive)
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switch {
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case gainQ16[0] != 210944:
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t.Fatal()
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case gainQ16[1] != 112640:
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t.Fatal()
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case gainQ16[2] != 96256:
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t.Fatal()
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case gainQ16[3] != 96256:
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if !reflect.DeepEqual(gainQ16, []float64{210944, 112640, 96256, 96256}) {
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t.Fatal()
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}
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}
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@ -99,6 +92,40 @@ func TestNormalizeLineSpectralFrequencyCoefficients(t *testing.T) {
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}
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}
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func TestNormalizeLSFInterpolation(t *testing.T) {
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t.Run("wQ2 == 4", func(t *testing.T) {
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d := &Decoder{rangeDecoder: createRangeDecoder(testSilkFrame(), 55, 493249168, 174371199)}
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n2Q15 := []int16{
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2132, 3584, 5504, 7424, 9472, 11392, 13440, 15360, 17280,
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19200, 21120, 23040, 25088, 27008, 28928, 30848,
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}
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if !reflect.DeepEqual(d.normalizeLSFInterpolation(n2Q15), n2Q15) {
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t.Fatal()
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}
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})
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t.Run("wQ2 == 1", func(t *testing.T) {
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frame := []byte{0xac, 0xbd, 0xa9, 0xf7, 0x26, 0x24, 0x5a, 0xa4, 0x00, 0x37, 0xbf, 0x9c, 0xde, 0xe, 0xcf, 0x94, 0x64, 0xaa, 0xf9, 0x87, 0xd0, 0x79, 0x19, 0xa8, 0x21, 0xc0}
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d := &Decoder{
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rangeDecoder: createRangeDecoder(frame, 65, 1231761776, 1068195183),
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haveDecoded: true,
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n0Q15: []int16{
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518, 380, 4444, 6982, 8752, 10510, 12381, 14102, 15892, 17651, 19340, 21888, 23936, 25984, 28160, 30208,
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},
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}
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n2Q15 := []int16{215, 1447, 3712, 5120, 7168, 9088, 11264, 13184, 15232, 17536, 19712, 21888, 24192, 26240, 28416, 30336}
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expectedN1Q15 := []int16{
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442, 646, 4261, 6516, 8356, 10154, 12101, 13872, 15727,
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17622, 19433, 21888, 24000, 26048, 28224, 30240,
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}
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if !reflect.DeepEqual(d.normalizeLSFInterpolation(n2Q15), expectedN1Q15) {
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t.Fatal()
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}
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})
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}
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func TestConvertNormalizedLSFsToLPCCoefficients(t *testing.T) {
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d := &Decoder{}
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