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feat: simplify vpr decode

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This commit is contained in:
Unlock Music Dev 2022-11-19 07:25:39 +08:00
parent e6ba9f0bfa
commit a2c55721cc
Signed by untrusted user: um-dev
GPG Key ID: 95202E10D3413A1D
2 changed files with 48 additions and 45 deletions
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14
algo/kgm/kgm.go
View File

@ -21,7 +21,7 @@ var (
type Decoder struct {
file []byte
key []byte
isVpr bool
maskFunc func(int) byte
audio []byte
}
@ -49,9 +49,9 @@ func (d *Decoder) GetMeta() common.Meta {
func (d *Decoder) Validate() error {
if bytes.Equal(kgmHeader, d.file[:len(kgmHeader)]) {
d.isVpr = false
d.maskFunc = getKgmMask
} else if bytes.Equal(vprHeader, d.file[:len(vprHeader)]) {
d.isVpr = true
d.maskFunc = getVprMask
} else {
return ErrKgmMagicHeader
}
@ -67,14 +67,10 @@ func (d *Decoder) Decode() error {
d.audio = d.file[headerLen:]
for i := 0; i < len(d.audio); i++ {
med8 := d.audio[i] ^ d.key[i%17] ^ maskV2PreDef[i%(16*17)] ^ getKgmMaskV2(i>>4)
med8 := d.audio[i] ^ d.key[i%17] ^ d.maskFunc(i)
d.audio[i] = med8 ^ (med8&0xf)<<4
}
if d.isVpr {
for i := 0; i < len(d.audio); i++ {
d.audio[i] ^= maskDiffVpr[i%17]
}
}
return nil
}
func init() {

73
algo/kgm/mask.go
View File

@ -4,32 +4,7 @@ import (
_ "embed"
)
var maskDiffVpr = []byte{
0x25, 0xDF, 0xE8, 0xA6, 0x75, 0x1E, 0x75, 0x0E,
0x2F, 0x80, 0xF3, 0x2D, 0xB8, 0xB6, 0xE3, 0x11,
0x00}
var maskV2PreDef = []byte{
0xB8, 0xD5, 0x3D, 0xB2, 0xE9, 0xAF, 0x78, 0x8C, 0x83, 0x33, 0x71, 0x51, 0x76, 0xA0, 0xCD, 0x37,
0x2F, 0x3E, 0x35, 0x8D, 0xA9, 0xBE, 0x98, 0xB7, 0xE7, 0x8C, 0x22, 0xCE, 0x5A, 0x61, 0xDF, 0x68,
0x69, 0x89, 0xFE, 0xA5, 0xB6, 0xDE, 0xA9, 0x77, 0xFC, 0xC8, 0xBD, 0xBD, 0xE5, 0x6D, 0x3E, 0x5A,
0x36, 0xEF, 0x69, 0x4E, 0xBE, 0xE1, 0xE9, 0x66, 0x1C, 0xF3, 0xD9, 0x02, 0xB6, 0xF2, 0x12, 0x9B,
0x44, 0xD0, 0x6F, 0xB9, 0x35, 0x89, 0xB6, 0x46, 0x6D, 0x73, 0x82, 0x06, 0x69, 0xC1, 0xED, 0xD7,
0x85, 0xC2, 0x30, 0xDF, 0xA2, 0x62, 0xBE, 0x79, 0x2D, 0x62, 0x62, 0x3D, 0x0D, 0x7E, 0xBE, 0x48,
0x89, 0x23, 0x02, 0xA0, 0xE4, 0xD5, 0x75, 0x51, 0x32, 0x02, 0x53, 0xFD, 0x16, 0x3A, 0x21, 0x3B,
0x16, 0x0F, 0xC3, 0xB2, 0xBB, 0xB3, 0xE2, 0xBA, 0x3A, 0x3D, 0x13, 0xEC, 0xF6, 0x01, 0x45, 0x84,
0xA5, 0x70, 0x0F, 0x93, 0x49, 0x0C, 0x64, 0xCD, 0x31, 0xD5, 0xCC, 0x4C, 0x07, 0x01, 0x9E, 0x00,
0x1A, 0x23, 0x90, 0xBF, 0x88, 0x1E, 0x3B, 0xAB, 0xA6, 0x3E, 0xC4, 0x73, 0x47, 0x10, 0x7E, 0x3B,
0x5E, 0xBC, 0xE3, 0x00, 0x84, 0xFF, 0x09, 0xD4, 0xE0, 0x89, 0x0F, 0x5B, 0x58, 0x70, 0x4F, 0xFB,
0x65, 0xD8, 0x5C, 0x53, 0x1B, 0xD3, 0xC8, 0xC6, 0xBF, 0xEF, 0x98, 0xB0, 0x50, 0x4F, 0x0F, 0xEA,
0xE5, 0x83, 0x58, 0x8C, 0x28, 0x2C, 0x84, 0x67, 0xCD, 0xD0, 0x9E, 0x47, 0xDB, 0x27, 0x50, 0xCA,
0xF4, 0x63, 0x63, 0xE8, 0x97, 0x7F, 0x1B, 0x4B, 0x0C, 0xC2, 0xC1, 0x21, 0x4C, 0xCC, 0x58, 0xF5,
0x94, 0x52, 0xA3, 0xF3, 0xD3, 0xE0, 0x68, 0xF4, 0x00, 0x23, 0xF3, 0x5E, 0x0A, 0x7B, 0x93, 0xDD,
0xAB, 0x12, 0xB2, 0x13, 0xE8, 0x84, 0xD7, 0xA7, 0x9F, 0x0F, 0x32, 0x4C, 0x55, 0x1D, 0x04, 0x36,
0x52, 0xDC, 0x03, 0xF3, 0xF9, 0x4E, 0x42, 0xE9, 0x3D, 0x61, 0xEF, 0x7C, 0xB6, 0xB3, 0x93, 0x50,
}
var kgmMaskTable1 = []byte{
var kgmMaskTable1 = [...]byte{
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x01, 0x21, 0x01, 0x61, 0x01, 0x21, 0x01, 0xe1, 0x01, 0x21, 0x01, 0x61, 0x01, 0x21, 0x01,
0xd2, 0x23, 0x02, 0x02, 0x42, 0x42, 0x02, 0x02, 0xc2, 0xc2, 0x02, 0x02, 0x42, 0x42, 0x02, 0x02,
@ -49,7 +24,7 @@ var kgmMaskTable1 = []byte{
0x00, 0x20, 0x00, 0x60, 0x00, 0x20, 0x00, 0xe0, 0x00, 0x20, 0x00, 0x60, 0x00, 0x20, 0x00, 0xf1,
}
var kgmMaskTable2 = []byte{
var kgmMaskTable2 = [...]byte{
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x01, 0x23, 0x01, 0x67, 0x01, 0x23, 0x01, 0xef, 0x01, 0x23, 0x01, 0x67, 0x01, 0x23, 0x01,
0xdf, 0x21, 0x02, 0x02, 0x46, 0x46, 0x02, 0x02, 0xce, 0xce, 0x02, 0x02, 0x46, 0x46, 0x02, 0x02,
@ -69,13 +44,45 @@ var kgmMaskTable2 = []byte{
0x00, 0x22, 0x00, 0x66, 0x00, 0x22, 0x00, 0xee, 0x00, 0x22, 0x00, 0x66, 0x00, 0x22, 0x00, 0xfe,
}
func getKgmMaskV2(offset int) byte {
ret := byte(0)
for offset >= 0x11 {
ret ^= kgmMaskTable1[offset%272]
var kgmMaskTable3 = [...]byte{
0xB8, 0xD5, 0x3D, 0xB2, 0xE9, 0xAF, 0x78, 0x8C, 0x83, 0x33, 0x71, 0x51, 0x76, 0xA0, 0xCD, 0x37,
0x2F, 0x3E, 0x35, 0x8D, 0xA9, 0xBE, 0x98, 0xB7, 0xE7, 0x8C, 0x22, 0xCE, 0x5A, 0x61, 0xDF, 0x68,
0x69, 0x89, 0xFE, 0xA5, 0xB6, 0xDE, 0xA9, 0x77, 0xFC, 0xC8, 0xBD, 0xBD, 0xE5, 0x6D, 0x3E, 0x5A,
0x36, 0xEF, 0x69, 0x4E, 0xBE, 0xE1, 0xE9, 0x66, 0x1C, 0xF3, 0xD9, 0x02, 0xB6, 0xF2, 0x12, 0x9B,
0x44, 0xD0, 0x6F, 0xB9, 0x35, 0x89, 0xB6, 0x46, 0x6D, 0x73, 0x82, 0x06, 0x69, 0xC1, 0xED, 0xD7,
0x85, 0xC2, 0x30, 0xDF, 0xA2, 0x62, 0xBE, 0x79, 0x2D, 0x62, 0x62, 0x3D, 0x0D, 0x7E, 0xBE, 0x48,
0x89, 0x23, 0x02, 0xA0, 0xE4, 0xD5, 0x75, 0x51, 0x32, 0x02, 0x53, 0xFD, 0x16, 0x3A, 0x21, 0x3B,
0x16, 0x0F, 0xC3, 0xB2, 0xBB, 0xB3, 0xE2, 0xBA, 0x3A, 0x3D, 0x13, 0xEC, 0xF6, 0x01, 0x45, 0x84,
0xA5, 0x70, 0x0F, 0x93, 0x49, 0x0C, 0x64, 0xCD, 0x31, 0xD5, 0xCC, 0x4C, 0x07, 0x01, 0x9E, 0x00,
0x1A, 0x23, 0x90, 0xBF, 0x88, 0x1E, 0x3B, 0xAB, 0xA6, 0x3E, 0xC4, 0x73, 0x47, 0x10, 0x7E, 0x3B,
0x5E, 0xBC, 0xE3, 0x00, 0x84, 0xFF, 0x09, 0xD4, 0xE0, 0x89, 0x0F, 0x5B, 0x58, 0x70, 0x4F, 0xFB,
0x65, 0xD8, 0x5C, 0x53, 0x1B, 0xD3, 0xC8, 0xC6, 0xBF, 0xEF, 0x98, 0xB0, 0x50, 0x4F, 0x0F, 0xEA,
0xE5, 0x83, 0x58, 0x8C, 0x28, 0x2C, 0x84, 0x67, 0xCD, 0xD0, 0x9E, 0x47, 0xDB, 0x27, 0x50, 0xCA,
0xF4, 0x63, 0x63, 0xE8, 0x97, 0x7F, 0x1B, 0x4B, 0x0C, 0xC2, 0xC1, 0x21, 0x4C, 0xCC, 0x58, 0xF5,
0x94, 0x52, 0xA3, 0xF3, 0xD3, 0xE0, 0x68, 0xF4, 0x00, 0x23, 0xF3, 0x5E, 0x0A, 0x7B, 0x93, 0xDD,
0xAB, 0x12, 0xB2, 0x13, 0xE8, 0x84, 0xD7, 0xA7, 0x9F, 0x0F, 0x32, 0x4C, 0x55, 0x1D, 0x04, 0x36,
0x52, 0xDC, 0x03, 0xF3, 0xF9, 0x4E, 0x42, 0xE9, 0x3D, 0x61, 0xEF, 0x7C, 0xB6, 0xB3, 0x93, 0x50,
}
func getKgmMask(i int) byte {
offset := i >> 4
value := byte(0)
for offset >= 17 {
value ^= kgmMaskTable1[offset%(16*17)]
offset = offset >> 4
ret ^= kgmMaskTable2[offset%272]
value ^= kgmMaskTable2[offset%(16*17)]
offset = offset >> 4
}
return ret
return kgmMaskTable3[i%(16*17)] ^ value
}
var vprMaskDiffKgm = []byte{
0x75, 0x2F, 0x68, 0xC6, 0x25, 0xFE, 0x25, 0xEE,
0xDF, 0x80, 0xC3, 0xFD, 0x38, 0xD6, 0xD3, 0x01,
0x00,
}
func getVprMask(i int) byte {
return vprMaskDiffKgm[i%17] ^ getKgmMask(i)
}