gotosocial/vendor/github.com/abema/go-mp4/probe.go

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