func (x *residue) ReadFrom(r *ogg.BitReader) error {
x.residueType = r.Read16(16)
if x.residueType > 2 {
return ogg.ErrCorruptStream
}
x.begin = r.Read32(24)
x.end = r.Read32(24)
x.partitionSize = r.Read32(24) + 1
x.classifications = r.Read8(6) + 1
x.classbook = r.Read8(8)
x.cascade = make([]uint8, x.classifications)
for i := range x.cascade {
highBits := uint8(0)
lowBits := r.Read8(3)
if r.ReadBool() {
highBits = r.Read8(5)
}
x.cascade[i] = highBits*8 + lowBits
}
x.books = make([][8]uint8, x.classifications)
for i := range x.books {
for j := 0; j < 8; j++ {
if x.cascade[i]&(1<<uint(j)) != 0 {
x.books[i][j] = r.Read8(8)
} else {
x.books[i][j] = 0xFF //unused
}
}
}
return nil
}
func (f *floor1) Decode(r *ogg.BitReader, books []codebook, n uint32) []uint32 {
if !r.ReadBool() {
return nil
}
range_ := [4]uint32{256, 128, 86, 64}[f.multiplier-1]
y := make([]uint32, 0, len(f.xList))
y = append(y, r.Read32(ilog(int(range_)-1)), r.Read32(ilog(int(range_)-1)))
for _, classIndex := range f.partitionClassList {
class := f.classes[classIndex]
cdim := class.dimension
cbits := class.subclass
csub := (uint32(1) << cbits) - 1
cval := uint32(0)
if cbits > 0 {
cval = books[class.masterbook].DecodeScalar(r)
}
for j := 0; j < int(cdim); j++ {
book := class.subclassBooks[cval&csub]
cval >>= cbits
if book != 0xFF {
y = append(y, books[book].DecodeScalar(r))
} else {
y = append(y, 0)
}
}
}
return y
}
func (i *identification) ReadFrom(r *ogg.BitReader) error {
if r.Read8(8) != headerTypeIdentification {
return ogg.ErrCorruptStream
}
if r.Read64(48) != pattern {
return ogg.ErrCorruptStream
}
if r.Read32(32) != 0 {
return ogg.ErrCorruptStream
}
i.audioChannels = r.Read8(8)
i.audioSampleRate = r.Read32(32)
i.bitrateMaximum = r.Read32(32)
i.bitrateNominal = r.Read32(32)
i.bitrateMinimum = r.Read32(32)
i.blocksize0 = uint16(1) << r.Read8(4)
i.blocksize1 = uint16(1) << r.Read8(4)
if !r.ReadBool() {
return ogg.ErrCorruptStream
}
return nil
}
func (s *setup) ReadFrom(r *ogg.BitReader) error {
if r.Read8(8) != headerTypeSetup {
return ogg.ErrCorruptStream
}
if r.Read64(48) != pattern {
return ogg.ErrCorruptStream
}
// CODEBOOKS
s.codebooks = make([]codebook, r.Read16(8)+1)
for i := range s.codebooks {
err := s.codebooks[i].ReadFrom(r)
if err != nil {
return err
}
}
// TIME DOMAIN TRANSFORMS
transformCount := r.Read8(6) + 1
for i := 0; i < int(transformCount); i++ {
if r.Read16(16) != 0 {
return ogg.ErrCorruptStream
}
}
// FLOORS
s.floors = make([]floor, r.Read8(6)+1)
for i := range s.floors {
var err error
switch r.Read16(16) {
case 0:
// TODO
// floor0 is not supported right now, also I haven't found any files that use it.
/*var f floor0
err = f.ReadFrom(r)
s.floors[i] = &f*/
case 1:
f := new(floor1)
err = f.ReadFrom(r)
s.floors[i] = f
default:
err = ogg.ErrCorruptStream
}
if err != nil {
return err
}
}
// RESIDUES
s.residues = make([]residue, r.Read8(6)+1)
for i := range s.residues {
err := s.residues[i].ReadFrom(r)
if err != nil {
return err
}
}
// MAPPINGS
s.mappings = make([]mapping, r.Read8(6)+1)
for i := range s.mappings {
m := &s.mappings[i]
if r.Read16(16) != 0 {
return ogg.ErrCorruptStream
}
if r.ReadBool() {
m.submaps = make([]mappingSubmap, r.Read8(4)+1)
} else {
m.submaps = make([]mappingSubmap, 1)
}
if r.ReadBool() {
m.couplingSteps = r.Read16(8) + 1
m.magnitude = make([]uint8, m.couplingSteps)
m.angle = make([]uint8, m.couplingSteps)
for i := range m.magnitude {
m.magnitude[i] = r.Read8(ilog(s.channels - 1))
m.angle[i] = r.Read8(ilog(s.channels - 1))
}
}
if r.Read8(2) != 0 {
return ogg.ErrCorruptStream
}
m.mux = make([]uint8, s.channels)
if len(m.submaps) > 1 {
for i := range m.mux {
m.mux[i] = r.Read8(4)
}
}
for i := range m.submaps {
r.Read8(8)
m.submaps[i].floor = r.Read8(8)
m.submaps[i].residue = r.Read8(8)
}
}
// MODES
s.modes = make([]mode, r.Read8(6)+1)
for i := range s.modes {
m := &s.modes[i]
m.blockflag = r.Read8(1)
if r.Read16(16) != 0 {
return ogg.ErrCorruptStream
}
if r.Read16(16) != 0 {
return ogg.ErrCorruptStream
}
m.mapping = r.Read8(8)
}
if !r.ReadBool() {
return ogg.ErrCorruptStream
}
return nil
}
func (c *codebook) ReadFrom(r *ogg.BitReader) error {
if r.Read32(24) != codebookPattern {
return ogg.ErrCorruptStream
}
c.dimensions = r.Read32(16)
numEntries := r.Read32(24)
c.entries = make(huffmanTable, numEntries*2-2)
ordered := r.ReadBool()
if !ordered {
sparse := r.ReadBool()
for i := uint32(0); i < numEntries; i++ {
if !sparse || r.ReadBool() {
c.entries.Put(i, r.Read8(5)+1)
}
}
} else {
currentEntry := uint32(0)
currentLength := r.Read8(5) + 1
for currentEntry < numEntries {
num := r.Read32(ilog(int(numEntries - currentEntry)))
for i := currentEntry; i < currentEntry+num; i++ {
c.entries.Put(i, currentLength)
}
currentEntry += num
currentLength++
}
}
lookupType := r.Read8(4)
if lookupType == 0 {
return nil
}
if lookupType > 2 {
return ogg.ErrCorruptStream
}
minimumValue := float32Unpack(r.Read32(32))
deltaValue := float32Unpack(r.Read32(32))
valueBits := r.Read8(4) + 1
sequenceP := r.ReadBool()
var multiplicands []uint32
if lookupType == 1 {
multiplicands = make([]uint32, lookup1Values(int(numEntries), c.dimensions))
} else {
multiplicands = make([]uint32, int(numEntries)*int(c.dimensions))
}
for i := range multiplicands {
multiplicands[i] = r.Read32(uint(valueBits))
}
c.values = make([]float32, numEntries*c.dimensions)
for entry := 0; entry < int(numEntries); entry++ {
index := entry * int(c.dimensions)
if lookupType == 1 {
last := float32(0)
indexDivisor := 1
for i := 0; i < int(c.dimensions); i++ {
multiplicandOffset := (entry / indexDivisor) % len(multiplicands)
c.values[index+i] = float32(multiplicands[multiplicandOffset])*deltaValue + minimumValue + last
if sequenceP {
last = c.values[index+i]
}
indexDivisor *= len(multiplicands)
}
} else if lookupType == 2 {
last := float32(0)
for i := 0; i < int(c.dimensions); i++ {
c.values[index+i] = float32(multiplicands[index+i])*deltaValue + minimumValue + last
if sequenceP {
last = c.values[index+i]
}
}
}
}
return nil
}
func (s *setup) decodePacket(r *ogg.BitReader, prev [][]float32) ([][]float32, [][]float32, error) {
if r.ReadBool() {
return nil, nil, ogg.ErrCorruptStream
}
modeNumber := r.Read8(ilog(len(s.modes) - 1))
mode := s.modes[modeNumber]
// decode window type
blocktype := mode.blockflag
longWindow := mode.blockflag == 1
blocksize := s.blocksize[blocktype]
spectrumSize := uint32(blocksize / 2)
windowPrev, windowNext := false, false
window := windowType{blocksize, blocksize, blocksize}
if longWindow {
windowPrev = r.ReadBool()
windowNext = r.ReadBool()
if !windowPrev {
window.prev = s.blocksize[0]
}
if !windowNext {
window.next = s.blocksize[0]
}
}
mapping := &s.mappings[mode.mapping]
floors := make([]floorData, s.channels)
residueVectors := make([][]float32, s.channels)
for ch := range residueVectors {
residueVectors[ch] = s.residueBuffer[ch][:spectrumSize]
for i := range residueVectors[ch] {
residueVectors[ch][i] = 0
}
}
s.decodeFloors(r, floors, mapping, spectrumSize)
s.decodeResidue(r, residueVectors, mapping, floors, spectrumSize)
s.inverseCoupling(mapping, residueVectors)
s.applyFloor(floors, residueVectors)
// inverse MDCT
out := make([][]float32, s.channels)
for ch := range out {
out[ch] = make([]float32, blocksize)
imdct(s.lookup[blocktype], residueVectors[ch], out[ch])
}
// apply window and overlap
s.applyWindow(&window, out)
center := blocksize / 2
offset := s.blocksize[1]/4 - s.blocksize[0]/4
final := make([][]float32, s.channels)
next := make([][]float32, s.channels)
if longWindow {
for ch := range out {
start := 0
end := blocksize
if !windowPrev {
start += offset
}
if !windowNext {
end -= offset
}
final[ch], next[ch] = out[ch][start:center], out[ch][center:end]
if prev != nil {
for i := range prev[ch] {
final[ch][i] += prev[ch][i]
}
}
}
} else /*short window*/ {
for ch := range out {
if prev != nil && len(prev[ch]) > center {
final[ch], next[ch] = prev[ch], out[ch][center:]
for i := offset; i < len(final[ch]); i++ {
final[ch][i] += out[ch][i-offset]
}
} else {
final[ch], next[ch] = out[ch][:center], out[ch][center:]
if prev != nil {
for i := range final[ch] {
final[ch][i] += prev[ch][i]
}
}
}
}
}
return final, next, nil
}