mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-11-15 22:11:04 +00:00
684 lines
16 KiB
Go
684 lines
16 KiB
Go
package mp4
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import (
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"bytes"
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"errors"
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"io"
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"github.com/abema/go-mp4/internal/bitio"
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)
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type ProbeInfo struct {
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MajorBrand [4]byte
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MinorVersion uint32
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CompatibleBrands [][4]byte
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FastStart bool
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Timescale uint32
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Duration uint64
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Tracks Tracks
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Segments Segments
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}
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// Deprecated: replace with ProbeInfo
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type FraProbeInfo = ProbeInfo
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type Tracks []*Track
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// Deprecated: replace with Track
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type TrackInfo = Track
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type Track struct {
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TrackID uint32
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Timescale uint32
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Duration uint64
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Codec Codec
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Encrypted bool
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EditList EditList
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Samples Samples
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Chunks Chunks
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AVC *AVCDecConfigInfo
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MP4A *MP4AInfo
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}
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type Codec int
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const (
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CodecUnknown Codec = iota
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CodecAVC1
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CodecMP4A
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)
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type EditList []*EditListEntry
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type EditListEntry struct {
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MediaTime int64
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SegmentDuration uint64
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}
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type Samples []*Sample
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type Sample struct {
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Size uint32
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TimeDelta uint32
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CompositionTimeOffset int64
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}
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type Chunks []*Chunk
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type Chunk struct {
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DataOffset uint64
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SamplesPerChunk uint32
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}
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type AVCDecConfigInfo struct {
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ConfigurationVersion uint8
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Profile uint8
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ProfileCompatibility uint8
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Level uint8
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LengthSize uint16
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Width uint16
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Height uint16
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}
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type MP4AInfo struct {
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OTI uint8
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AudOTI uint8
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ChannelCount uint16
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}
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type Segments []*Segment
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// Deprecated: replace with Segment
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type SegmentInfo = Segment
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type Segment struct {
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TrackID uint32
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MoofOffset uint64
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BaseMediaDecodeTime uint64
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DefaultSampleDuration uint32
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SampleCount uint32
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Duration uint32
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CompositionTimeOffset int32
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Size uint32
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}
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// Probe probes MP4 file
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func Probe(r io.ReadSeeker) (*ProbeInfo, error) {
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probeInfo := &ProbeInfo{
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Tracks: make([]*Track, 0, 8),
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Segments: make([]*Segment, 0, 8),
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}
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bis, err := ExtractBoxes(r, nil, []BoxPath{
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{BoxTypeFtyp()},
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{BoxTypeMoov()},
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{BoxTypeMoov(), BoxTypeMvhd()},
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{BoxTypeMoov(), BoxTypeTrak()},
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{BoxTypeMoof()},
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{BoxTypeMdat()},
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})
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if err != nil {
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return nil, err
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}
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var mdatAppeared bool
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for _, bi := range bis {
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switch bi.Type {
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case BoxTypeFtyp():
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var ftyp Ftyp
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if _, err := bi.SeekToPayload(r); err != nil {
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return nil, err
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}
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if _, err := Unmarshal(r, bi.Size-bi.HeaderSize, &ftyp, bi.Context); err != nil {
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return nil, err
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}
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probeInfo.MajorBrand = ftyp.MajorBrand
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probeInfo.MinorVersion = ftyp.MinorVersion
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probeInfo.CompatibleBrands = make([][4]byte, 0, len(ftyp.CompatibleBrands))
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for _, entry := range ftyp.CompatibleBrands {
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probeInfo.CompatibleBrands = append(probeInfo.CompatibleBrands, entry.CompatibleBrand)
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}
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case BoxTypeMoov():
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probeInfo.FastStart = !mdatAppeared
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case BoxTypeMvhd():
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var mvhd Mvhd
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if _, err := bi.SeekToPayload(r); err != nil {
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return nil, err
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}
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if _, err := Unmarshal(r, bi.Size-bi.HeaderSize, &mvhd, bi.Context); err != nil {
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return nil, err
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}
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probeInfo.Timescale = mvhd.Timescale
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if mvhd.GetVersion() == 0 {
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probeInfo.Duration = uint64(mvhd.DurationV0)
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} else {
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probeInfo.Duration = mvhd.DurationV1
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}
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case BoxTypeTrak():
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track, err := probeTrak(r, bi)
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if err != nil {
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return nil, err
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}
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probeInfo.Tracks = append(probeInfo.Tracks, track)
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case BoxTypeMoof():
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segment, err := probeMoof(r, bi)
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if err != nil {
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return nil, err
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}
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probeInfo.Segments = append(probeInfo.Segments, segment)
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case BoxTypeMdat():
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mdatAppeared = true
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}
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}
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return probeInfo, nil
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}
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// ProbeFra probes fragmented MP4 file
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// Deprecated: replace with Probe
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func ProbeFra(r io.ReadSeeker) (*FraProbeInfo, error) {
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probeInfo, err := Probe(r)
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return (*FraProbeInfo)(probeInfo), err
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}
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func probeTrak(r io.ReadSeeker, bi *BoxInfo) (*Track, error) {
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track := new(Track)
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bips, err := ExtractBoxesWithPayload(r, bi, []BoxPath{
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{BoxTypeTkhd()},
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{BoxTypeEdts(), BoxTypeElst()},
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{BoxTypeMdia(), BoxTypeMdhd()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsd(), BoxTypeAvc1()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsd(), BoxTypeAvc1(), BoxTypeAvcC()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsd(), BoxTypeEncv()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsd(), BoxTypeEncv(), BoxTypeAvcC()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsd(), BoxTypeMp4a()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsd(), BoxTypeMp4a(), BoxTypeEsds()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsd(), BoxTypeMp4a(), BoxTypeWave(), BoxTypeEsds()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsd(), BoxTypeEnca()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsd(), BoxTypeEnca(), BoxTypeEsds()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStco()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeCo64()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStts()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeCtts()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsc()},
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{BoxTypeMdia(), BoxTypeMinf(), BoxTypeStbl(), BoxTypeStsz()},
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})
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if err != nil {
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return nil, err
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}
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var tkhd *Tkhd
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var elst *Elst
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var mdhd *Mdhd
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var avc1 *VisualSampleEntry
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var avcC *AVCDecoderConfiguration
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var audioSampleEntry *AudioSampleEntry
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var esds *Esds
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var stco *Stco
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var stts *Stts
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var stsc *Stsc
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var ctts *Ctts
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var stsz *Stsz
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var co64 *Co64
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for _, bip := range bips {
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switch bip.Info.Type {
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case BoxTypeTkhd():
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tkhd = bip.Payload.(*Tkhd)
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case BoxTypeElst():
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elst = bip.Payload.(*Elst)
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case BoxTypeMdhd():
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mdhd = bip.Payload.(*Mdhd)
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case BoxTypeAvc1():
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track.Codec = CodecAVC1
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avc1 = bip.Payload.(*VisualSampleEntry)
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case BoxTypeAvcC():
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avcC = bip.Payload.(*AVCDecoderConfiguration)
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case BoxTypeEncv():
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track.Codec = CodecAVC1
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track.Encrypted = true
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case BoxTypeMp4a():
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track.Codec = CodecMP4A
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audioSampleEntry = bip.Payload.(*AudioSampleEntry)
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case BoxTypeEnca():
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track.Codec = CodecMP4A
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track.Encrypted = true
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audioSampleEntry = bip.Payload.(*AudioSampleEntry)
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case BoxTypeEsds():
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esds = bip.Payload.(*Esds)
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case BoxTypeStco():
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stco = bip.Payload.(*Stco)
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case BoxTypeStts():
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stts = bip.Payload.(*Stts)
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case BoxTypeStsc():
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stsc = bip.Payload.(*Stsc)
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case BoxTypeCtts():
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ctts = bip.Payload.(*Ctts)
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case BoxTypeStsz():
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stsz = bip.Payload.(*Stsz)
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case BoxTypeCo64():
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co64 = bip.Payload.(*Co64)
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}
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}
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if tkhd == nil {
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return nil, errors.New("tkhd box not found")
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}
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track.TrackID = tkhd.TrackID
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if elst != nil {
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editList := make([]*EditListEntry, 0, len(elst.Entries))
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for i := range elst.Entries {
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editList = append(editList, &EditListEntry{
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MediaTime: elst.GetMediaTime(i),
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SegmentDuration: elst.GetSegmentDuration(i),
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})
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}
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track.EditList = editList
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}
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if mdhd == nil {
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return nil, errors.New("mdhd box not found")
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}
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track.Timescale = mdhd.Timescale
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track.Duration = mdhd.GetDuration()
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if avc1 != nil && avcC != nil {
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track.AVC = &AVCDecConfigInfo{
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ConfigurationVersion: avcC.ConfigurationVersion,
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Profile: avcC.Profile,
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ProfileCompatibility: avcC.ProfileCompatibility,
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Level: avcC.Level,
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LengthSize: uint16(avcC.LengthSizeMinusOne) + 1,
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Width: avc1.Width,
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Height: avc1.Height,
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}
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}
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if audioSampleEntry != nil && esds != nil {
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oti, audOTI, err := detectAACProfile(esds)
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if err != nil {
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return nil, err
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}
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track.MP4A = &MP4AInfo{
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OTI: oti,
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AudOTI: audOTI,
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ChannelCount: audioSampleEntry.ChannelCount,
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}
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}
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track.Chunks = make([]*Chunk, 0)
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if stco != nil {
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for _, offset := range stco.ChunkOffset {
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track.Chunks = append(track.Chunks, &Chunk{
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DataOffset: uint64(offset),
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})
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}
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} else if co64 != nil {
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for _, offset := range co64.ChunkOffset {
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track.Chunks = append(track.Chunks, &Chunk{
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DataOffset: offset,
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})
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}
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} else {
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return nil, errors.New("stco/co64 box not found")
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}
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if stts == nil {
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return nil, errors.New("stts box not found")
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}
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track.Samples = make([]*Sample, 0)
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for _, entry := range stts.Entries {
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for i := uint32(0); i < entry.SampleCount; i++ {
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track.Samples = append(track.Samples, &Sample{
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TimeDelta: entry.SampleDelta,
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})
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}
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}
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if stsc == nil {
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return nil, errors.New("stsc box not found")
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}
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for si, entry := range stsc.Entries {
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end := uint32(len(track.Chunks))
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if si != len(stsc.Entries)-1 && stsc.Entries[si+1].FirstChunk-1 < end {
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end = stsc.Entries[si+1].FirstChunk - 1
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}
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for ci := entry.FirstChunk - 1; ci < end; ci++ {
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track.Chunks[ci].SamplesPerChunk = entry.SamplesPerChunk
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}
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}
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if ctts != nil {
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var si uint32
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for ci, entry := range ctts.Entries {
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for i := uint32(0); i < entry.SampleCount; i++ {
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if si >= uint32(len(track.Samples)) {
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break
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}
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track.Samples[si].CompositionTimeOffset = ctts.GetSampleOffset(ci)
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si++
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}
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}
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}
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if stsz != nil {
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for i := 0; i < len(stsz.EntrySize) && i < len(track.Samples); i++ {
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track.Samples[i].Size = stsz.EntrySize[i]
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}
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}
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return track, nil
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}
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func detectAACProfile(esds *Esds) (oti, audOTI uint8, err error) {
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configDscr := findDescriptorByTag(esds.Descriptors, DecoderConfigDescrTag)
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if configDscr == nil || configDscr.DecoderConfigDescriptor == nil {
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return 0, 0, nil
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}
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if configDscr.DecoderConfigDescriptor.ObjectTypeIndication != 0x40 {
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return configDscr.DecoderConfigDescriptor.ObjectTypeIndication, 0, nil
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}
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specificDscr := findDescriptorByTag(esds.Descriptors, DecSpecificInfoTag)
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if specificDscr == nil {
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return 0, 0, errors.New("DecoderSpecificationInfoDescriptor not found")
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}
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r := bitio.NewReader(bytes.NewReader(specificDscr.Data))
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remaining := len(specificDscr.Data) * 8
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// audio object type
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audioObjectType, read, err := getAudioObjectType(r)
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if err != nil {
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return 0, 0, err
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}
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remaining -= read
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// sampling frequency index
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samplingFrequencyIndex, err := r.ReadBits(4)
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if err != nil {
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return 0, 0, err
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}
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remaining -= 4
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if samplingFrequencyIndex[0] == 0x0f {
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if _, err = r.ReadBits(24); err != nil {
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return 0, 0, err
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}
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remaining -= 24
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}
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if audioObjectType == 2 && remaining >= 20 {
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if _, err = r.ReadBits(4); err != nil {
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return 0, 0, err
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}
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remaining -= 4
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syncExtensionType, err := r.ReadBits(11)
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if err != nil {
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return 0, 0, err
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}
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remaining -= 11
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if syncExtensionType[0] == 0x2 && syncExtensionType[1] == 0xb7 {
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extAudioObjectType, _, err := getAudioObjectType(r)
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if err != nil {
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return 0, 0, err
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}
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if extAudioObjectType == 5 || extAudioObjectType == 22 {
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sbr, err := r.ReadBits(1)
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if err != nil {
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return 0, 0, err
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}
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remaining--
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if sbr[0] != 0 {
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if extAudioObjectType == 5 {
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sfi, err := r.ReadBits(4)
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if err != nil {
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return 0, 0, err
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}
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remaining -= 4
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if sfi[0] == 0xf {
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if _, err := r.ReadBits(24); err != nil {
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return 0, 0, err
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}
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remaining -= 24
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}
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if remaining >= 12 {
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syncExtensionType, err := r.ReadBits(11)
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if err != nil {
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return 0, 0, err
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}
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if syncExtensionType[0] == 0x5 && syncExtensionType[1] == 0x48 {
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ps, err := r.ReadBits(1)
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if err != nil {
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return 0, 0, err
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}
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if ps[0] != 0 {
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return 0x40, 29, nil
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}
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}
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}
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}
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return 0x40, 5, nil
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}
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}
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}
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}
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return 0x40, audioObjectType, nil
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}
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func findDescriptorByTag(dscrs []Descriptor, tag int8) *Descriptor {
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for _, dscr := range dscrs {
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if dscr.Tag == tag {
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return &dscr
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}
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}
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return nil
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}
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func getAudioObjectType(r bitio.Reader) (byte, int, error) {
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audioObjectType, err := r.ReadBits(5)
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if err != nil {
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return 0, 0, err
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}
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if audioObjectType[0] != 0x1f {
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return audioObjectType[0], 5, nil
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}
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audioObjectType, err = r.ReadBits(6)
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if err != nil {
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return 0, 0, err
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}
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return audioObjectType[0] + 32, 11, nil
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}
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func probeMoof(r io.ReadSeeker, bi *BoxInfo) (*Segment, error) {
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bips, err := ExtractBoxesWithPayload(r, bi, []BoxPath{
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{BoxTypeTraf(), BoxTypeTfhd()},
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{BoxTypeTraf(), BoxTypeTfdt()},
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{BoxTypeTraf(), BoxTypeTrun()},
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})
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if err != nil {
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return nil, err
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}
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var tfhd *Tfhd
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var tfdt *Tfdt
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var trun *Trun
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segment := &Segment{
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MoofOffset: bi.Offset,
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}
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for _, bip := range bips {
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switch bip.Info.Type {
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case BoxTypeTfhd():
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tfhd = bip.Payload.(*Tfhd)
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case BoxTypeTfdt():
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tfdt = bip.Payload.(*Tfdt)
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case BoxTypeTrun():
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trun = bip.Payload.(*Trun)
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}
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}
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if tfhd == nil {
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return nil, errors.New("tfhd not found")
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}
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segment.TrackID = tfhd.TrackID
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segment.DefaultSampleDuration = tfhd.DefaultSampleDuration
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if tfdt != nil {
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if tfdt.Version == 0 {
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segment.BaseMediaDecodeTime = uint64(tfdt.BaseMediaDecodeTimeV0)
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} else {
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segment.BaseMediaDecodeTime = tfdt.BaseMediaDecodeTimeV1
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}
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}
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if trun != nil {
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segment.SampleCount = trun.SampleCount
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if trun.CheckFlag(0x000100) {
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segment.Duration = 0
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for ei := range trun.Entries {
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segment.Duration += trun.Entries[ei].SampleDuration
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}
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} else {
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segment.Duration = tfhd.DefaultSampleDuration * segment.SampleCount
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}
|
|
|
|
if trun.CheckFlag(0x000200) {
|
|
segment.Size = 0
|
|
for ei := range trun.Entries {
|
|
segment.Size += trun.Entries[ei].SampleSize
|
|
}
|
|
} else {
|
|
segment.Size = tfhd.DefaultSampleSize * segment.SampleCount
|
|
}
|
|
|
|
var duration uint32
|
|
for ei := range trun.Entries {
|
|
offset := int32(duration) + int32(trun.GetSampleCompositionTimeOffset(ei))
|
|
if ei == 0 || offset < segment.CompositionTimeOffset {
|
|
segment.CompositionTimeOffset = offset
|
|
}
|
|
if trun.CheckFlag(0x000100) {
|
|
duration += trun.Entries[ei].SampleDuration
|
|
} else {
|
|
duration += tfhd.DefaultSampleDuration
|
|
}
|
|
}
|
|
}
|
|
|
|
return segment, nil
|
|
}
|
|
|
|
func FindIDRFrames(r io.ReadSeeker, trackInfo *TrackInfo) ([]int, error) {
|
|
if trackInfo.AVC == nil {
|
|
return nil, nil
|
|
}
|
|
lengthSize := uint32(trackInfo.AVC.LengthSize)
|
|
|
|
var si int
|
|
idxs := make([]int, 0, 8)
|
|
for _, chunk := range trackInfo.Chunks {
|
|
end := si + int(chunk.SamplesPerChunk)
|
|
dataOffset := chunk.DataOffset
|
|
for ; si < end && si < len(trackInfo.Samples); si++ {
|
|
sample := trackInfo.Samples[si]
|
|
if sample.Size == 0 {
|
|
continue
|
|
}
|
|
for nalOffset := uint32(0); nalOffset+lengthSize+1 <= sample.Size; {
|
|
if _, err := r.Seek(int64(dataOffset+uint64(nalOffset)), io.SeekStart); err != nil {
|
|
return nil, err
|
|
}
|
|
data := make([]byte, lengthSize+1)
|
|
if _, err := io.ReadFull(r, data); err != nil {
|
|
return nil, err
|
|
}
|
|
var length uint32
|
|
for i := 0; i < int(lengthSize); i++ {
|
|
length = (length << 8) + uint32(data[i])
|
|
}
|
|
nalHeader := data[lengthSize]
|
|
nalType := nalHeader & 0x1f
|
|
if nalType == 5 {
|
|
idxs = append(idxs, si)
|
|
break
|
|
}
|
|
nalOffset += lengthSize + length
|
|
}
|
|
dataOffset += uint64(sample.Size)
|
|
}
|
|
}
|
|
return idxs, nil
|
|
}
|
|
|
|
func (samples Samples) GetBitrate(timescale uint32) uint64 {
|
|
var totalSize uint64
|
|
var totalDuration uint64
|
|
for _, sample := range samples {
|
|
totalSize += uint64(sample.Size)
|
|
totalDuration += uint64(sample.TimeDelta)
|
|
}
|
|
if totalDuration == 0 {
|
|
return 0
|
|
}
|
|
return 8 * totalSize * uint64(timescale) / totalDuration
|
|
}
|
|
|
|
func (samples Samples) GetMaxBitrate(timescale uint32, timeDelta uint64) uint64 {
|
|
if timeDelta == 0 {
|
|
return 0
|
|
}
|
|
var maxBitrate uint64
|
|
var size uint64
|
|
var duration uint64
|
|
var begin int
|
|
var end int
|
|
for end < len(samples) {
|
|
for {
|
|
size += uint64(samples[end].Size)
|
|
duration += uint64(samples[end].TimeDelta)
|
|
end++
|
|
if duration >= timeDelta || end == len(samples) {
|
|
break
|
|
}
|
|
}
|
|
bitrate := 8 * size * uint64(timescale) / duration
|
|
if bitrate > maxBitrate {
|
|
maxBitrate = bitrate
|
|
}
|
|
for {
|
|
size -= uint64(samples[begin].Size)
|
|
duration -= uint64(samples[begin].TimeDelta)
|
|
begin++
|
|
if duration < timeDelta {
|
|
break
|
|
}
|
|
}
|
|
}
|
|
return maxBitrate
|
|
}
|
|
|
|
func (segments Segments) GetBitrate(trackID uint32, timescale uint32) uint64 {
|
|
var totalSize uint64
|
|
var totalDuration uint64
|
|
for _, segment := range segments {
|
|
if segment.TrackID == trackID {
|
|
totalSize += uint64(segment.Size)
|
|
totalDuration += uint64(segment.Duration)
|
|
}
|
|
}
|
|
if totalDuration == 0 {
|
|
return 0
|
|
}
|
|
return 8 * totalSize * uint64(timescale) / totalDuration
|
|
}
|
|
|
|
func (segments Segments) GetMaxBitrate(trackID uint32, timescale uint32) uint64 {
|
|
var maxBitrate uint64
|
|
for _, segment := range segments {
|
|
if segment.TrackID == trackID && segment.Duration != 0 {
|
|
bitrate := 8 * uint64(segment.Size) * uint64(timescale) / uint64(segment.Duration)
|
|
if bitrate > maxBitrate {
|
|
maxBitrate = bitrate
|
|
}
|
|
}
|
|
}
|
|
return maxBitrate
|
|
}
|