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removed duplicated code
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@csiwek
csiwek committed Aug 1, 2019
1 parent 29013f3 commit 6d2caaa
Showing 1 changed file with 50 additions and 106 deletions.
156 changes: 50 additions & 106 deletions opus.go
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@ type OpusReader struct {
CurrentSampleDuration uint32
currentSamples uint32
currentSegment uint8
payloadLen uint32
segments uint8
currentSample uint8
segmentMap map[uint8]uint8
Expand All @@ -47,69 +48,53 @@ func NewFile(fileName string) (*OpusReader, error) {
//}
reader.fd = f
reader.stream = bufio.NewReader(f)
_, err = reader.getPage()
err = reader.getPage()
if err != nil {
return reader, err
}
_, err = reader.getPage()
err = reader.getPage()
if err != nil {
return reader, err
}
reader.segmentMap = make(map[uint8]uint8)
return reader, nil
}

func (i *OpusReader) readOpusHead() (uint32, error) {
var plen uint32
func (i *OpusReader) readOpusHead() error {
var version uint8
magic := make([]byte, 8)
if err := binary.Read(i.stream, binary.LittleEndian, &magic); err != err {
return 0, err
return err
}
if bytes.Compare(magic, []byte("OpusHead")) != 0 {
return 0, errors.New("Wrong Opus Head")
return errors.New("Wrong Opus Head")
}

if err := binary.Read(i.stream, binary.LittleEndian, &version); err != err {
return 0, err
return err
}
plen += 1
fmt.Printf("Version: %v\n", version)
var channels uint8
if err := binary.Read(i.stream, binary.LittleEndian, &channels); err != err {
return 0, err
return err
}

fmt.Printf("Channels: %v\n", channels)

var preSkip uint16
if err := binary.Read(i.stream, binary.LittleEndian, &preSkip); err != err {
return 0, err
return err
}
plen += 2
fmt.Printf("preSkip: %v\n", preSkip)

if err := binary.Read(i.stream, binary.LittleEndian, &i.sampleRate); err != err {
return 0, err
return err
}
plen += 4
fmt.Printf("SamlpleRate: %v\n", i.sampleRate)
//Skipping OutputGain
io.CopyN(ioutil.Discard, i.stream, 2)
plen += 2
var channelMap uint8
if err := binary.Read(i.stream, binary.LittleEndian, &channelMap); err != err {
return 0, err
return err
}
plen += 2
fmt.Printf("ChannelMap : %v\n", channelMap)
//if channelMap (Mapping family) is different than 0, next 4 bytes contain channel mapping configuration

if channelMap != 0 {
io.CopyN(ioutil.Discard, i.stream, 4)
plen += 4
}
return plen, nil
return nil
}

func (i *OpusReader) readOpusTags() (uint32, error) {
Expand Down Expand Up @@ -149,118 +134,86 @@ func (i *OpusReader) readOpusTags() (uint32, error) {

}

func (i *OpusReader) getPage() ([]byte, error) {
payload := make([]byte, 1)
func (i *OpusReader) getPageHead() error {
head := make([]byte, 4)
if err := binary.Read(i.stream, binary.LittleEndian, &head); err != err {
return payload, err
return err
}
if bytes.Compare(head, []byte("OggS")) != 0 {
return payload, fmt.Errorf("Incorrect page. Does not start with \"OggS\" : %s %v", string(head), hex.EncodeToString(head))
return fmt.Errorf("Incorrect page. Does not start with \"OggS\" : %s %v", string(head), hex.EncodeToString(head))
}
//Skipping Version
io.CopyN(ioutil.Discard, i.stream, 1)
var headerType uint8
if err := binary.Read(i.stream, binary.LittleEndian, &headerType); err != err {
return payload, err
return err
}
var granulePosition uint64
if err := binary.Read(i.stream, binary.LittleEndian, &granulePosition); err != err {
return payload, err
return err
}
if err := binary.Read(i.stream, binary.LittleEndian, &i.serial); err != err {
return payload, err
return err
}
if err := binary.Read(i.stream, binary.LittleEndian, &i.pageIndex); err != err {
return payload, err
return err
}
//skipping checksum
io.CopyN(ioutil.Discard, i.stream, 4)

var segments uint8
if err := binary.Read(i.stream, binary.LittleEndian, &segments); err != err {
return payload, err
if err := binary.Read(i.stream, binary.LittleEndian, &i.segments); err != err {
return err
}

i.previousGranulePosition = granulePosition

var payloadLen uint32
// Iterating through all segments calculate the complete packet size
for x := 1; x <= int(segments); x++ {
var x uint8
// building a map of all segments
i.payloadLen = 0
for x = 1; x <= i.segments; x++ {
var segSize uint8
if err := binary.Read(i.stream, binary.LittleEndian, &segSize); err != err {
return payload, err
return err
}
payloadLen = payloadLen + uint32(segSize)
i.segmentMap[x] = segSize
i.payloadLen += uint32(segSize)
}
i.currentSegment = 1
return nil
}

func (i *OpusReader) getPage() error {
err := i.getPageHead()
if err != nil {
return err

}

if i.pageIndex == 0 {
_, err := i.readOpusHead()
err := i.readOpusHead()
if err != nil {
return payload, err
return err
}
} else if i.pageIndex == 1 {
plen, err := i.readOpusTags()
if err != nil {
return payload, err
return err
}
// we are not interested in tags (metadata?)
io.CopyN(ioutil.Discard, i.stream, int64(payloadLen-plen))
io.CopyN(ioutil.Discard, i.stream, int64(i.payloadLen-plen))

} else {
tmpPacket := make([]byte, payloadLen)
binary.Read(i.stream, binary.LittleEndian, &tmpPacket)
return tmpPacket, nil
io.CopyN(ioutil.Discard, i.stream, int64(i.payloadLen))
}

return payload, nil
return nil
}

func (i *OpusReader) getPageSingle() ([]byte, error) {
func (i *OpusReader) getPageSample() ([]byte, error) {
if i.currentSegment == 0 {
payload := make([]byte, 1)
head := make([]byte, 4)
if err := binary.Read(i.stream, binary.LittleEndian, &head); err != err {
return payload, err
}
if bytes.Compare(head, []byte("OggS")) != 0 {
return payload, fmt.Errorf("Incorrect page. Does not start with \"OggS\" : %s %v", string(head), hex.EncodeToString(head))
}
//Skipping Version
io.CopyN(ioutil.Discard, i.stream, 1)
var headerType uint8
if err := binary.Read(i.stream, binary.LittleEndian, &headerType); err != err {
return payload, err
}
var granulePosition uint64
if err := binary.Read(i.stream, binary.LittleEndian, &granulePosition); err != err {
return payload, err
}
if err := binary.Read(i.stream, binary.LittleEndian, &i.serial); err != err {
return payload, err
}
if err := binary.Read(i.stream, binary.LittleEndian, &i.pageIndex); err != err {
return payload, err
}
//skipping checksum
io.CopyN(ioutil.Discard, i.stream, 4)

if err := binary.Read(i.stream, binary.LittleEndian, &i.segments); err != err {
return payload, err
}
i.calculateSampleDuration(uint32(granulePosition - i.previousGranulePosition))
i.previousGranulePosition = granulePosition

var x uint8
// building a map of all segments
for x = 1; x <= i.segments; x++ {
var segSize uint8
if err := binary.Read(i.stream, binary.LittleEndian, &segSize); err != err {
return payload, err
}
i.segmentMap[x] = segSize
err := i.getPageHead()
if err != nil {
return []byte(""), err

}
i.currentSegment = 1
}
var currentPacketSize uint32
// Iteraring throug all segments to check if there are lacing packets. If a segment is 255 bytes long, it means that there must be a following segment for the same packet (which may be again 255 bytes long)
Expand Down Expand Up @@ -340,17 +293,8 @@ func getFrameSize(toc uint8) float32 {

}

func (i *OpusReader) GetSample() ([]byte, error) {
payload, err := i.getPage()
if err != nil {
return nil, err
}

return payload, nil
}

func (i *OpusReader) GetSingleSample() ([]byte, error) {
payload, err := i.getPageSingle()
payload, err := i.getPageSample()
if err != nil {
return nil, err
}
Expand Down

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