Finish decoder Excitation
Implements final part https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.6
This commit is contained in:
Sean DuBois
parent
8412cf5190
commit
b5ea7c4523
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@ -580,24 +580,17 @@ func (d *Decoder) decodePulseAndLSBCounts(shellblocks int, rateLevel uint32) (pu
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return
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}
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// SILK codes the excitation using a modified version of the Pyramid
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// Vector Quantizer (PVQ) codebook [PVQ]. The PVQ codebook is designed
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// for Laplace-distributed values and consists of all sums of K signed,
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// unit pulses in a vector of dimension N, where two pulses at the same
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// position are required to have the same sign.
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// The locations of the pulses in each shell block follow the pulse
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// counts. As with the pulse counts, these locations are coded for all the shell blocks
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// before any of the remaining information for each block. Unlike many
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// other codecs, SILK places no restriction on the distribution of
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// pulses within a shell block. All of the pulses may be placed in a
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// single location, or each one in a unique location, or anything in
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// between.
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8
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func (d *Decoder) decodeExcitation(signalType frameSignalType, quantizationOffsetType frameQuantizationOffsetType, lcgSeed uint32, pulsecounts, lsbcounts []uint8) {
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// The locations of the pulses in each shell block follow the pulse
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// counts. As with the pulse counts, these locations are coded for all the shell blocks
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// before any of the remaining information for each block. Unlike many
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// other codecs, SILK places no restriction on the distribution of
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// pulses within a shell block. All of the pulses may be placed in a
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// single location, or each one in a unique location, or anything in
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// between.
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.3
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excitation := make([]int32, len(pulsecounts)*pulsecountLargestPartitionSize)
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.3
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func (d *Decoder) decodePulseLocation(pulsecounts []uint8) (eRaw []int32) {
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eRaw = make([]int32, len(pulsecounts)*pulsecountLargestPartitionSize)
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for i := range pulsecounts {
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// This process skips partitions without any pulses, i.e., where
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// the initial pulse count from Section 4.2.7.8.2 was zero, or where the
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@ -608,7 +601,7 @@ func (d *Decoder) decodeExcitation(signalType frameSignalType, quantizationOffse
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continue
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}
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excitationIndex := pulsecountLargestPartitionSize * i
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eRawIndex := pulsecountLargestPartitionSize * i
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samplePartition16 := make([]uint8, 2)
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samplePartition8 := make([]uint8, 2)
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samplePartition4 := make([]uint8, 2)
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@ -625,38 +618,44 @@ func (d *Decoder) decodeExcitation(signalType frameSignalType, quantizationOffse
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d.partitionPulseCount(icdfPulseCountSplit4SamplePartitions, samplePartition8[k], samplePartition4)
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for l := 0; l < 2; l++ {
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d.partitionPulseCount(icdfPulseCountSplit2SamplePartitions, samplePartition4[l], samplePartition2)
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excitation[excitationIndex] = int32(samplePartition2[0])
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excitationIndex++
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eRaw[eRawIndex] = int32(samplePartition2[0])
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eRawIndex++
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excitation[excitationIndex] = int32(samplePartition2[1])
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excitationIndex++
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eRaw[eRawIndex] = int32(samplePartition2[1])
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eRawIndex++
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}
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}
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}
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}
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// After the decoder reads the pulse locations for all blocks, it reads
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// the LSBs (if any) for each block in turn. Inside each block, it
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// reads all the LSBs for each coefficient in turn, even those where no
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// pulses were allocated, before proceeding to the next one.
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.4
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for i := 0; i < len(excitation); i++ {
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return
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}
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// After the decoder reads the pulse locations for all blocks, it reads
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// the LSBs (if any) for each block in turn. Inside each block, it
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// reads all the LSBs for each coefficient in turn, even those where no
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// pulses were allocated, before proceeding to the next one.
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.4
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func (d *Decoder) decodeExcitationLSB(eRaw []int32, lsbcounts []uint8) {
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for i := 0; i < len(eRaw); i++ {
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for bit := uint8(0); bit < lsbcounts[i/pulsecountLargestPartitionSize]; bit++ {
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excitation[i] = (excitation[i] << 1) | int32(d.rangeDecoder.DecodeSymbolWithICDF(icdfExcitationLSB))
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eRaw[i] = (eRaw[i] << 1) | int32(d.rangeDecoder.DecodeSymbolWithICDF(icdfExcitationLSB))
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}
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}
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}
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// After decoding the pulse locations and the LSBs, the decoder knows
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// the magnitude of each coefficient in the excitation.
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.5
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for i := 0; i < len(excitation); i++ {
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// After decoding the pulse locations and the LSBs, the decoder knows
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// the magnitude of each coefficient in the excitation.
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.5
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func (d *Decoder) decodeExcitationSign(eRaw []int32, signalType frameSignalType, quantizationOffsetType frameQuantizationOffsetType, pulsecounts []uint8) {
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for i := 0; i < len(eRaw); i++ {
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// It then decodes a sign for all coefficients
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// with a non-zero magnitude
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.5
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if excitation[i] == 0 {
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if eRaw[i] == 0 {
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continue
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}
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@ -786,20 +785,26 @@ func (d *Decoder) decodeExcitation(signalType frameSignalType, quantizationOffse
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// If the value decoded is 0, then the coefficient magnitude is negated.
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// Otherwise, it remains positive.
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if d.rangeDecoder.DecodeSymbolWithICDF(icdf) == 0 {
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excitation[i] *= -1
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eRaw[i] *= -1
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}
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}
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for f := range excitation {
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fmt.Println(excitation[f])
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}
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}
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// SILK codes the excitation using a modified version of the Pyramid
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// Vector Quantizer (PVQ) codebook [PVQ]. The PVQ codebook is designed
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// for Laplace-distributed values and consists of all sums of K signed,
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// unit pulses in a vector of dimension N, where two pulses at the same
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// position are required to have the same sign.
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8
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func (d *Decoder) decodeExcitation(signalType frameSignalType, quantizationOffsetType frameQuantizationOffsetType, seed uint32, pulsecounts, lsbcounts []uint8) (eQ23 []int32) {
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// After the signs have been read, there is enough information to
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// reconstruct the complete excitation signal. This requires adding a
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// constant quantization offset to each non-zero sample and then
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// pseudorandomly inverting and offsetting every sample.
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//
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.5
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// https://datatracker.ietf.org/doc/html/rfc6716#section-4.2.7.8.6
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// The constant quantization offset varies depending on the signal type and
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// quantization offset type
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@ -821,7 +826,7 @@ func (d *Decoder) decodeExcitation(signalType frameSignalType, quantizationOffse
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// | Voiced | High | 25 |
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// +-------------+--------------------------+--------------------------+
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// Table 53: Excitation Quantization Offsets
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var offsetQ23 int
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var offsetQ23 int32
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switch {
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case signalType == frameSignalTypeInactive && quantizationOffsetType == frameQuantizationOffsetTypeLow:
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offsetQ23 = 25
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@ -837,11 +842,18 @@ func (d *Decoder) decodeExcitation(signalType frameSignalType, quantizationOffse
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offsetQ23 = 25
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}
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for i := 0; i < len(excitation); i++ {
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// Let e_raw[i] be the raw excitation value at position i,
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// with a magnitude composed of the pulses at that location (see Section 4.2.7.8.3)
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// combined with any additional LSBs (see Section 4.2.7.8.4),
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// and with the corresponding sign decoded in Section 4.2.7.8.5.
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// Let e_raw[i] be the raw excitation value at position i,
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// with a magnitude composed of the pulses at that location (see Section 4.2.7.8.3)
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eRaw := d.decodePulseLocation(pulsecounts)
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// combined with any additional LSBs (see Section 4.2.7.8.4),
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d.decodeExcitationLSB(eRaw, lsbcounts)
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// and with the corresponding sign decoded in Section 4.2.7.8.5.
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d.decodeExcitationSign(eRaw, signalType, quantizationOffsetType, pulsecounts)
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eQ23 = make([]int32, len(eRaw))
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for i := 0; i < len(eRaw); i++ {
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// Additionally, let seed be the current pseudorandom seed, which is initialized to the
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// value decoded from Section 4.2.7.7 for the first sample in the current SILK frame, and
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// updated for each subsequent sample according to the procedure below.
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@ -859,8 +871,15 @@ func (d *Decoder) decodeExcitation(signalType frameSignalType, quantizationOffse
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// e_Q23[i] value may require more than 16 bits per sample, but it will
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// not require more than 23, including the sign.
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panic(offsetQ23)
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eQ23[i] = (eRaw[i] << 8) - int32(sign(int(eRaw[i])))*20 + offsetQ23
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seed = (196314165*seed + 907633515) & 0xFFFFFFFF
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if seed&0x80000000 != 0 {
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eQ23[i] *= -1
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}
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seed = (seed + uint32(eRaw[i])) & 0xFFFFFFFF
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}
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return
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}
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// The PDF to use is chosen by the size of the current partition (16, 8, 4, or 2) and the
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@ -99,6 +99,28 @@ func TestNormalizeLineSpectralFrequencyCoefficients(t *testing.T) {
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}
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func TestExcitation(t *testing.T) {
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expected := []int32{
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25, -25, -25, -25, 25, 25, -25, 25, 25, -25, 25, -25, -25, -25, 25, 25, -25,
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25, 25, 25, 25, -211, -25, -25, 25, -25, 25, -25, 25, -25, -25, -25, 25, 25,
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-25, -25, 261, 517, -25, 25, -25, -25, -25, -25, -25, -25, 25, -25, -25, 25,
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-25, 25, -25, 25, 25, 25, 25, -25, 25, -25, 25, 25, 25, 25, -25, 25, 25, 25,
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25, -25, -25, -25, -25, -25, -25, -25, 25, 25, -25, 25, 211, 25, -25, -25,
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25, 211, 25, 25, 25, -25, 25, 25, -25, -25, -25, 25, 25, 25, 25, -25, 25, 25,
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-25, 25, 25, 25, 25, 25, -25, -25, 25, -25, -25, 25, 25, -25, 25, 25, 25, -25,
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-25, -25, -25, -25, -25, 25, 25, 25, 25, 25, -25, 25, -25, -25, 25, 25, 25, 25,
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25, 25, 25, -25, 25, -211, 25, -25, -25, 25, 25, -25, -25, -25, -25, -25, -25,
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-25, 25, 25, -25, -25, 25, 25, -25, 25, -25, -25, -25, 25, 25, -25, 25, -25, -211,
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-25, 25, 25, 25, -25, -25, -25, -25, 25, 25, -25, -25, 25, -25, -25, 25, 25, 25,
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-25, -25, -25, -25, -25, 25, 25, -25, -211, 25, -25, 25, 25, -25, -25, 25, -25,
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25, -25, 25, 25, -25, -211, -25, 25, 25, -25, 25, 25, -25, -211, -25, 25, 25, 25,
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-25, -25, -25, -25, 25, -211, 25, 25, 25, 25, 25, 25, -25, -25, 25, -25, 517, 517,
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-467, -25, 25, 25, -25, -25, 25, -25, 25, 25, 25, -25, -25, -25, 25, 25, -25, -25,
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25, -25, 25, -25, 25, -25, 25, -25, -25, -25, 25, 25, -25, -25, 211, 25, 25, 25, 25,
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-25, -25, 25, -25, -25, -25, -25, 211, -25, 25, -25, -25, 25, -25, -25, 25,
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-25, 25, -25, 25, 25, -25, 25, -25, 25, 25, 25, 25, -25, -25, -25, 25, -25, 25, 25,
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-25, -25, -25, 25,
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}
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silkFrame := []byte{0x84, 0x2e, 0x67, 0xd3, 0x85, 0x65, 0x54, 0xe3, 0x9d, 0x90, 0x0a, 0xfa, 0x98, 0xea, 0xfd, 0x98, 0x94, 0x41, 0xf9, 0x6d, 0x1d, 0xa0}
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d := &Decoder{rangeDecoder: createRangeDecoder(silkFrame, 71, 851775140, 846837397)}
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@ -107,5 +129,8 @@ func TestExcitation(t *testing.T) {
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rateLevel := d.decodeRatelevel(false)
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pulsecounts, lsbcounts := d.decodePulseAndLSBCounts(shellblocks, rateLevel)
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d.decodeExcitation(frameSignalTypeUnvoiced, frameQuantizationOffsetTypeLow, lcgSeed, pulsecounts, lsbcounts)
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eRaw := d.decodeExcitation(frameSignalTypeUnvoiced, frameQuantizationOffsetTypeLow, lcgSeed, pulsecounts, lsbcounts)
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if !reflect.DeepEqual(expected, eRaw) {
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t.Fatal()
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}
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}
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