Create cache for res and out values
LTP Synthesis needs values of out + res for previous frames
This commit is contained in:
Sean DuBois
parent
903249e356
commit
3a79dec65f
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@ -25,6 +25,11 @@ type Decoder struct {
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// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.9.2
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finalLPCValues []float32
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// This requires storage to buffer up to 306 values of out[i] from
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// previous subframes.
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// https://www.rfc-editor.org/rfc/rfc6716#section-4.2.7.9.1
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finalOutValues []float32
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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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@ -34,6 +39,7 @@ type Decoder struct {
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func NewDecoder() Decoder {
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return Decoder{
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finalLPCValues: make([]float32, 16),
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finalOutValues: make([]float32, 306),
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}
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}
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@ -1077,14 +1083,14 @@ func (d *Decoder) limitLPCFilterPredictionGain(a32Q17 []int32) (aQ12 []float32)
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}
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// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.6.1
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func (d *Decoder) decodePitchLags(signalType frameSignalType, bandwidth Bandwidth) (lag uint32, pitchLags []int) {
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func (d *Decoder) decodePitchLags(signalType frameSignalType, bandwidth Bandwidth) (lagMax uint32, pitchLags []int) {
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if signalType != frameSignalTypeVoiced {
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return
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}
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var (
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lag uint32
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lagMin uint32
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lagMax uint32
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)
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// The primary lag index is coded either relative to the primary lag of
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@ -1348,7 +1354,7 @@ func (d *Decoder) ltpSynthesis(
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LTPScaleQ14 float32,
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bandwidth Bandwidth,
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wQ2 int16,
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aQ12, gainQ16, lpc, res []float32,
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aQ12, gainQ16, lpc, res, resLag []float32,
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) {
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// If this is the third or fourth subframe of a 20 ms SILK frame and the LSF
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// interpolation factor, w_Q2 (see Section 4.2.7.5.5), is less than 4,
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@ -1411,7 +1417,9 @@ func (d *Decoder) ltpSynthesis(
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// previous subframes (240 from the current SILK frame and 16 from the
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// previous SILK frame). This corresponds to WB with up to three
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// previous subframes in the current SILK frame, plus 16 samples for
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// d_LPC. The astute reader will notice that, given the definition of
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// d_LPC.
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// The astute reader will notice that, given the definition of
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// lpc[i] in Section 4.2.7.9.2, the output of this latter equation is
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// merely a scaled version of the values of res[i] from previous
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// subframes.
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@ -1482,6 +1490,11 @@ func (d *Decoder) ltpSynthesis(
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//
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// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.9.2
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func (d *Decoder) lpcSynthesis(out []float32, bandwidth Bandwidth, n, s, dLPC int, aQ12, res, gainQ16, lpc []float32) {
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// Shift left one subframe of samples
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for i := 0; i < len(d.finalOutValues)-n; i++ {
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d.finalOutValues[i] = d.finalOutValues[i+n]
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}
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finalLPCValuesIndex := 0
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// j be the index of the first sample in the residual corresponding to
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@ -1530,6 +1543,7 @@ func (d *Decoder) lpcSynthesis(out []float32, bandwidth Bandwidth, n, s, dLPC in
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// out[i] = clamp(-1.0, lpc[i], 1.0)
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//
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out[i] = clampFloat(-1.0, lpc[sampleIndex], 1.0)
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d.finalOutValues[len(d.finalOutValues)-n+i] = out[i]
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}
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}
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@ -1545,6 +1559,7 @@ func (d *Decoder) lpcSynthesis(out []float32, bandwidth Bandwidth, n, s, dLPC in
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func (d *Decoder) silkFrameReconstruction(
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signalType frameSignalType, bandwidth Bandwidth,
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dLPC int,
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lagMax uint32,
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bQ7 [][]int8,
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pitchLags []int,
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eQ23 []int32,
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@ -1569,6 +1584,7 @@ func (d *Decoder) silkFrameReconstruction(
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// res[i] = ---------
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// 2.0**23
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res := make([]float32, len(eQ23))
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resLag := make([]float32, lagMax)
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for i := range res {
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res[i] = float32(eQ23[i]) / 8388608.0
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}
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@ -1588,7 +1604,7 @@ func (d *Decoder) silkFrameReconstruction(
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//
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// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.9.1
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if signalType == frameSignalTypeVoiced {
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d.ltpSynthesis(out, signalType, bQ7, pitchLags, eQ23, n, j, s, dLPC, LTPscaleQ14, bandwidth, wQ2, aQ12, gainQ16, lpc, res)
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d.ltpSynthesis(out, signalType, bQ7, pitchLags, eQ23, n, j, s, dLPC, LTPscaleQ14, bandwidth, wQ2, aQ12, gainQ16, lpc, res, resLag)
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}
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//https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.9.2
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@ -1677,7 +1693,7 @@ func (d *Decoder) Decode(in []byte, out []float32, isStereo bool, nanoseconds in
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aQ12 := d.limitLPCFilterPredictionGain(a32Q17)
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// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.6.1
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_, pitchLags := d.decodePitchLags(signalType, bandwidth)
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lagMax, pitchLags := d.decodePitchLags(signalType, bandwidth)
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// https://www.rfc-editor.org/rfc/rfc6716.html#section-4.2.7.6.2
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bQ7 := d.decodeLTPFilterCoefficients(signalType)
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@ -1704,6 +1720,7 @@ func (d *Decoder) Decode(in []byte, out []float32, isStereo bool, nanoseconds in
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d.silkFrameReconstruction(
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signalType, bandwidth,
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dLPC,
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lagMax,
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bQ7,
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pitchLags,
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eQ23,
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@ -396,8 +396,8 @@ func TestDecodePitchLags(t *testing.T) {
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silkFrame := []byte{0xb4, 0xe2, 0x2c, 0xe, 0x10, 0x65, 0x1d, 0xa9, 0x7, 0x5c, 0x36, 0x8f, 0x96, 0x7b, 0xf4, 0x89, 0x41, 0x55, 0x98, 0x7a, 0x39, 0x2e, 0x6b, 0x71, 0xa4, 0x3, 0x70, 0xbf}
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d := &Decoder{rangeDecoder: createRangeDecoder(silkFrame, 73, 30770362, 1380489)}
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lag, pitchLags := d.decodePitchLags(frameSignalTypeVoiced, BandwidthWideband)
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if lag != 206 {
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lagMax, pitchLags := d.decodePitchLags(frameSignalTypeVoiced, BandwidthWideband)
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if lagMax != 288 {
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t.Fatal()
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}
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