mirror of https://bitbucket.org/ausocean/av.git
codec/h264/h264dec: added functions to get TrailingOnes and TotalCoeff as well as testing
The functions firstly derive the value of nC and then read the value of coeff_token from the BitReader. The table read prior and loaded into a 'map' is then used to get the corresponding values of TrailingOnes and TotalCoef.
This commit is contained in:
Saxon
parent
ee9281925e
commit
61a5065556
|
|
@ -55,6 +55,201 @@ func init() {
|
|||
}
|
||||
}
|
||||
|
||||
const (
|
||||
chromaDCLevel = iota
|
||||
intra16x16DCLevel
|
||||
intra16x16ACLevel
|
||||
cbIntra16x16DCLevel
|
||||
cbIntra16x16ACLevel
|
||||
crIntra16x16DCLevel
|
||||
crIntra16x16ACLevel
|
||||
lumaLevel4x4
|
||||
cbLevel4x4
|
||||
crLevel4x4
|
||||
)
|
||||
|
||||
// TODO: put this somewhere more appropriate once context is understood.
|
||||
type block struct {
|
||||
usingInterMbPredMode bool
|
||||
mbType int
|
||||
totalCoef int
|
||||
}
|
||||
|
||||
// parseTotalCoeffAndTrailingOnes will use logic provided in section 9.2.1 of
|
||||
// the specifications to obtain a value of nC, parse coeff_token from br and
|
||||
// then use table 9-5 to find corresponding values of TrailingOnes(coeff_token)
|
||||
// and TotalCoeff(coeff_token) which are then subsequently returned.
|
||||
func parseTotalCoeffAndTrailingOnes(
|
||||
br *bits.BitReader,
|
||||
ctx *SliceContext,
|
||||
usingMbPredMode bool,
|
||||
level,
|
||||
maxNumCoef,
|
||||
inBlockIdx int,
|
||||
) (totalCoeff, trailingOnes, nC, outBlockIdx int, err error) {
|
||||
if level == chromaDCLevel {
|
||||
if ctx.chromaArrayType == 1 {
|
||||
nC = -1
|
||||
} else {
|
||||
nC = -2
|
||||
}
|
||||
} else {
|
||||
// Steps 1,2 and 3.
|
||||
if level == intra16x16DCLevel || level == cbIntra16x16DCLevel || level == crIntra16x16DCLevel {
|
||||
outBlockIdx = 0
|
||||
}
|
||||
|
||||
// Step 4 derive blkA and blkB variables (blockA and blockB here).
|
||||
var mbAddr, blk [2]block
|
||||
switch level {
|
||||
case intra16x16DCLevel, intra16x16ACLevel, lumaLevel4x4:
|
||||
// TODO: clause 6.4.11.4
|
||||
panic("not implemented")
|
||||
case cbIntra16x16DCLevel, cbIntra16x16ACLevel, cbLevel4x4:
|
||||
// TODO: clause 6.4.11.6
|
||||
panic("not implemented")
|
||||
case crIntra16x16DCLevel, crIntra16x16ACLevel, crLevel4x4:
|
||||
// TODO: clause 6.4.11.6
|
||||
panic("not implemented")
|
||||
default:
|
||||
// TODO: clause 6.4.11.5
|
||||
panic("not implemented")
|
||||
}
|
||||
|
||||
var availableFlag [2]bool
|
||||
var n [2]int
|
||||
for i := range availableFlag {
|
||||
// Step 5.
|
||||
if !(!available(mbAddr[i]) || usingMbPredMode || ctx.ConstrainedIntraPred ||
|
||||
mbAddr[i].usingInterMbPredMode || ctx.nalType == 2 || ctx.nalType == 3 || ctx.nalType == 4) {
|
||||
availableFlag[i] = true
|
||||
}
|
||||
|
||||
// Step 6.
|
||||
if availableFlag[i] {
|
||||
switch {
|
||||
case mbAddr[i].mbType == pSkip || mbAddr[i].mbType == bSkip || (mbAddr[i].mbType != iPCM && resTransformCoeffLevelsZero(blk[i])):
|
||||
n[i] = 0
|
||||
case mbAddr[i].mbType == iPCM:
|
||||
n[i] = 16
|
||||
default:
|
||||
// TODO: how is this set ?
|
||||
// "Otherwise, nN is set equal to the value TotalCoeff( coeff_token ) of
|
||||
// the neighbouring block blkN."
|
||||
// Do we need to run this same process for this block, or assume it's
|
||||
// already happened?
|
||||
n[i] = blk[i].totalCoef
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Step 7 derive
|
||||
switch {
|
||||
case availableFlag[0] && availableFlag[1]:
|
||||
nC = (n[0] + n[1] + 1) >> 1
|
||||
case availableFlag[0]:
|
||||
nC = n[0]
|
||||
case availableFlag[1]:
|
||||
nC = n[1]
|
||||
default:
|
||||
nC = 0
|
||||
}
|
||||
}
|
||||
|
||||
trailingOnes, totalCoeff, _, err = readCoeffToken(br, nC)
|
||||
if err != nil {
|
||||
err = fmt.Errorf("could not get trailingOnes and totalCoeff vars, failed with error: %v", err)
|
||||
return
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
var (
|
||||
errInvalidNC = errors.New("invalid value of nC")
|
||||
errBadToken = errors.New("could not find coeff_token value in map")
|
||||
)
|
||||
|
||||
// readCoeffToken will read the coeff_token from br and find a match in the
|
||||
// coeff_token mapping table (table 9-5 in the specifications) given also nC.
|
||||
// The resultant TrailingOnes(coeff_token) and TotalCoeff(coeff_token) are
|
||||
// returned as well as the value of coeff_token.
|
||||
func readCoeffToken(br *bits.BitReader, nC int) (trailingOnes, totalCoeff, coeffToken int, err error) {
|
||||
// Get the number of leading zeros.
|
||||
var b uint64
|
||||
nZeros := -1
|
||||
for ; b == 0; nZeros++ {
|
||||
b, err = br.ReadBits(1)
|
||||
if err != nil {
|
||||
err = fmt.Errorf("could not read coeff_token leading zeros, failed with error: %v", err)
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
// Get the column idx for the map.
|
||||
var nCIdx int
|
||||
switch {
|
||||
case 0 <= nC && nC < 2:
|
||||
nCIdx = 0
|
||||
case 2 <= nC && nC < 4:
|
||||
nCIdx = 1
|
||||
case 4 <= nC && nC < 8:
|
||||
nCIdx = 2
|
||||
case 8 <= nC:
|
||||
nCIdx = 3
|
||||
case nC == -1:
|
||||
nCIdx = 4
|
||||
case nC == -2:
|
||||
nCIdx = 5
|
||||
default:
|
||||
err = errInvalidNC
|
||||
return
|
||||
}
|
||||
|
||||
// Get the value of coeff_token.
|
||||
val := b
|
||||
nBits := nZeros
|
||||
for {
|
||||
vars, ok := coeffTokenMap[nCIdx][nZeros][int(val)]
|
||||
if ok {
|
||||
trailingOnes = vars[0]
|
||||
totalCoeff = vars[1]
|
||||
coeffToken = int(val)
|
||||
return
|
||||
}
|
||||
|
||||
const maxCoeffTokenBits = 16
|
||||
if !ok && nBits == maxCoeffTokenBits {
|
||||
err = errBadToken
|
||||
return
|
||||
}
|
||||
|
||||
b, err = br.ReadBits(1)
|
||||
if err != nil {
|
||||
err = fmt.Errorf("could not read next bit of coeff_token, failed with error: %v", err)
|
||||
return
|
||||
}
|
||||
|
||||
nBits++
|
||||
val <<= 1
|
||||
val |= b
|
||||
}
|
||||
}
|
||||
|
||||
// TODO: implement this. From step 6 section 9.2.1. Will return true if "AC
|
||||
// residual transform coefficient levels of the neighbouring block blkN are
|
||||
// equal to 0 due to the corresponding bit of CodedBlockPatternLuma or
|
||||
// CodedBlockPatternChroma being equal to 0"
|
||||
func resTransformCoeffLevelsZero(b block) bool {
|
||||
panic("not implemented")
|
||||
return true
|
||||
}
|
||||
|
||||
// TODO: implement this
|
||||
func available(b block) bool {
|
||||
panic("not implemented")
|
||||
return true
|
||||
}
|
||||
|
||||
// The number of columns in the coeffTokenMap defined below. This is
|
||||
// representative of the number of defined nC ranges defined in table 9-5.
|
||||
const nColumns = 6
|
||||
|
|
|
|||
|
|
@ -136,3 +136,55 @@ func TestParseLevelPrefix(t *testing.T) {
|
|||
}
|
||||
}
|
||||
}
|
||||
|
||||
func TestReadCoeffToken(t *testing.T) {
|
||||
tests := []struct {
|
||||
// Input.
|
||||
nC int
|
||||
tokenBits string
|
||||
|
||||
// Expected.
|
||||
trailingOnes int
|
||||
totalCoeff int
|
||||
err error
|
||||
}{
|
||||
{
|
||||
nC: 5,
|
||||
tokenBits: "0001001",
|
||||
trailingOnes: 0,
|
||||
totalCoeff: 6,
|
||||
},
|
||||
{
|
||||
nC: -1,
|
||||
tokenBits: "0000000000111111111",
|
||||
err: errBadToken,
|
||||
},
|
||||
{
|
||||
nC: -3,
|
||||
tokenBits: "0001001",
|
||||
err: errInvalidNC,
|
||||
},
|
||||
}
|
||||
|
||||
for i, test := range tests {
|
||||
b, err := binToSlice(test.tokenBits)
|
||||
if err != nil {
|
||||
t.Errorf("converting bin string to slice failed with error: %v for test", err)
|
||||
continue
|
||||
}
|
||||
|
||||
gotTrailingOnes, gotTotalCoeff, _, gotErr := readCoeffToken(bits.NewBitReader(bytes.NewReader(b)), test.nC)
|
||||
if gotErr != test.err {
|
||||
t.Errorf("did not get expected error for test: %d\nGot: %v\nWant: %v\n", i, gotErr, test.err)
|
||||
continue
|
||||
}
|
||||
|
||||
if gotTrailingOnes != test.trailingOnes {
|
||||
t.Errorf("did not get expected TrailingOnes(coeff_token) for test %d\nGot: %v\nWant: %v\n", i, gotTrailingOnes, test.trailingOnes)
|
||||
}
|
||||
|
||||
if gotTotalCoeff != test.totalCoeff {
|
||||
t.Errorf("did not get expected TotalCoeff(coeff_token) for test %d\nGot: %v\nWant: %v\n", i, gotTotalCoeff, test.totalCoeff)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue