codec/h264/h264dec: renamed NalUnit function to NewNALUnit and cleaned it up

This commit is contained in:
Saxon 2019-07-19 20:20:33 +09:30
parent 24f6b2d12f
commit f11ba2b433
1 changed files with 65 additions and 69 deletions

View File

@ -1,23 +1,12 @@
package h264
import (
"bitbucket.org/ausocean/av/codec/h264/decode/bits"
"github.com/pkg/errors"
)
"io"
type NalUnit struct {
NumBytes int
ForbiddenZeroBit int
RefIdc int
Type int
SvcExtensionFlag int
Avc3dExtensionFlag int
SVCExtension *SVCExtension
ThreeDAVCExtension *ThreeDAVCExtension
MVCExtension *MVCExtension
EmulationPreventionThreeByte byte
rbsp []byte
}
"github.com/pkg/errors"
"bitbucket.org/ausocean/av/codec/h264/decode/bits"
)
type MVCExtension struct {
NonIdrFlag bool
@ -187,70 +176,80 @@ func NewSVCExtension(br *bits.BitReader) (*SVCExtension, error) {
return e, nil
}
func (n *NalUnit) RBSP() []byte {
return n.rbsp
type NALUnit struct {
ForbiddenZeroBit int
RefIdc int
Type int
SVCExtensionFlag int
AVC3dExtensionFlag int
SVCExtension *SVCExtension
ThreeDAVCExtension *ThreeDAVCExtension
MVCExtension *MVCExtension
EmulationPreventionThreeByte byte
RBSP []byte
}
func NewNalUnit(frame []byte, numBytesInNal int) (*NalUnit, error) {
logger.Printf("debug: reading %d byte NAL\n", numBytesInNal)
nalUnit := NalUnit{
NumBytes: numBytesInNal,
HeaderBytes: 1,
}
// TODO: pass in actual io.Reader to NewBitReader
br := bits.NewBitReader(nil)
func NewNALUnit(br *bits.BitReader) (*NALUnit, error) {
n := &NALUnit{}
err := readFields(br, []field{
{&nalUnit.ForbiddenZeroBit, "ForbiddenZeroBit", 1},
{&nalUnit.RefIdc, "NalRefIdc", 2},
{&nalUnit.Type, "NalUnitType", 5},
{&n.ForbiddenZeroBit, "ForbiddenZeroBit", 1},
{&n.RefIdc, "NalRefIdc", 2},
{&n.Type, "NalUnitType", 5},
})
if err != nil {
return nil, err
}
if nalUnit.Type == 14 || nalUnit.Type == 20 || nalUnit.Type == 21 {
if nalUnit.Type != 21 {
b, err := br.ReadBits(1)
if err != nil {
return nil, errors.Wrap(err, "could not read SvcExtensionFlag")
}
nalUnit.SvcExtensionFlag = int(b)
} else {
b, err := br.ReadBits(1)
if err != nil {
return nil, errors.Wrap(err, "could not read Avc3dExtensionFlag")
}
nalUnit.Avc3dExtensionFlag = int(b)
}
if nalUnit.SvcExtensionFlag == 1 {
NalUnitHeaderSvcExtension(&nalUnit, br)
nalUnit.HeaderBytes += 3
} else if nalUnit.Avc3dExtensionFlag == 1 {
NalUnitHeader3davcExtension(&nalUnit, br)
nalUnit.HeaderBytes += 2
} else {
NalUnitHeaderMvcExtension(&nalUnit, br)
nalUnit.HeaderBytes += 3
var headBytes, rbspBytes = 1, 0
// TODO: use consts for the NAL types here
if n.Type == 14 || n.Type == 20 || n.Type == 21 {
if n.Type != 21 {
n.SVCExtensionFlag, err = br.ReadBool()
if err != nil {
return nil, errors.Wrap(err, "could not read SVCExtensionFlag")
}
} else {
n.AVC3DExtensionFlag, err = br.ReadBool()
if err != nil {
return nil, errors.Wrap(err, "could not read AVC3DExtensionFlag")
}
}
if n.SVCExtensionFlag {
n.SVCExtension, err = NewSVCExtension(br)
if err != nil {
return nil, errors.Wrap(err, "could not parse SVCExtension")
}
n.HeaderBytes += 3
} else if n.AVC3DExtensionFlag {
n.ThreeDAVCExtension, err = NewThreeDAVCExtension(br)
if err != nil {
return nil, errors.Wrap(err, "could not parse ThreeDAVCExtension")
}
n.HeaderBytes += 2
} else {
n.MVCExtension, err = NewMVCExtension(br)
if err != nil {
return nil, errors.Wrap(err, "could not parse MVCExtension")
}
n.HeaderBytes += 3
}
}
logger.Printf("debug: found %d byte header. Reading body\n", nalUnit.HeaderBytes)
for i := nalUnit.HeaderBytes; i < nalUnit.NumBytes; i++ {
for moreRBSPData(br) {
next3Bytes, err := br.PeekBits(24)
if err != nil {
logger.Printf("error: while reading next 3 NAL bytes: %v\n", err)
break
if err != nil && errors.Cause(err) != io.EOF {
return nil, errors.Wrap("could not Peek next 3 bytes")
}
// Little odd, the err above and the i+2 check might be synonyms
if i+2 < nalUnit.NumBytes && next3Bytes == 0x000003 {
if next3Bytes == 0x000003 {
for j := 0; j < 2; j++ {
rbspByte, err := br.ReadBits(8)
if err != nil {
return nil, errors.Wrap(err, "could not read rbspByte")
}
nalUnit.rbsp = append(nalUnit.rbsp, byte(rbspByte))
n.rbsp = append(n.rbsp, byte(rbspByte))
}
i += 2
@ -259,18 +258,15 @@ func NewNalUnit(frame []byte, numBytesInNal int) (*NalUnit, error) {
if err != nil {
return nil, errors.Wrap(err, "could not read eptByte")
}
nalUnit.EmulationPreventionThreeByte = byte(eptByte)
n.EmulationPreventionThreeByte = byte(eptByte)
} else {
if b, err := br.ReadBits(8); err == nil {
nalUnit.rbsp = append(nalUnit.rbsp, byte(b))
} else {
logger.Printf("error: while reading byte %d of %d nal bytes: %v\n", i, nalUnit.NumBytes, err)
break
b, err := br.ReadBits(8)
if err != nil {
return nil, errors.Wrap(err, "could not read RBSP byte")
}
n.rbsp = append(n.rbsp, byte(b))
}
}
// nalUnit.rbsp = frame[nalUnit.HeaderBytes:]
logger.Printf("info: decoded %s NAL with %d RBSP bytes\n", NALUnitType[nalUnit.Type], len(nalUnit.rbsp))
return &nalUnit, nil
return n, nil
}