mp4

type Box ¶

type Box interface {
	Type() string
	Size() int
	Encode(w io.Writer) error
}

A box

func DecodeBox(h BoxHeader, r io.Reader) (Box, error)

func DecodeContainer(r io.Reader) ([]Box, error)

func DecodeCtts(r io.Reader) (Box, error)

func DecodeDinf(r io.Reader) (Box, error)

func DecodeDref(r io.Reader) (Box, error)

func DecodeEdts(r io.Reader) (Box, error)

func DecodeElst(r io.Reader) (Box, error)

func DecodeFree(r io.Reader) (Box, error)

func DecodeFtyp(r io.Reader) (Box, error)

func DecodeHdlr(r io.Reader) (Box, error)

func DecodeIods(r io.Reader) (Box, error)

func DecodeMdat(r io.Reader) (Box, error)

func DecodeMdhd(r io.Reader) (Box, error)

func DecodeMdia(r io.Reader) (Box, error)

func DecodeMeta(r io.Reader) (Box, error)

func DecodeMinf(r io.Reader) (Box, error)

func DecodeMoov(r io.Reader) (Box, error)

func DecodeMvhd(r io.Reader) (Box, error)

func DecodeSmhd(r io.Reader) (Box, error)

func DecodeStbl(r io.Reader) (Box, error)

func DecodeStco(r io.Reader) (Box, error)

func DecodeStsc(r io.Reader) (Box, error)

func DecodeStsd(r io.Reader) (Box, error)

func DecodeStss(r io.Reader) (Box, error)

func DecodeStsz(r io.Reader) (Box, error)

func DecodeStts(r io.Reader) (Box, error)

func DecodeTkhd(r io.Reader) (Box, error)

func DecodeTrak(r io.Reader) (Box, error)

func DecodeUdta(r io.Reader) (Box, error)

func DecodeVmhd(r io.Reader) (Box, error)

type BoxDecoder ¶

type BoxDecoder func(r io.Reader) (Box, error)

type BoxHeader ¶

type BoxHeader struct {
	Type string
	Size uint32
}

The header of a box

func DecodeHeader(r io.Reader) (BoxHeader, error)

type CttsBox ¶

type CttsBox struct {
	Version      byte
	Flags        [3]byte
	SampleCount  []uint32
	SampleOffset []uint32 // int32 for version 1
}

Composition Time to Sample Box (ctts - optional)

Contained in: Sample Table Box (stbl)

Status: version 0 decoded. version 1 uses int32 for offsets

func (b *CttsBox) Encode(w io.Writer) error

func (b *CttsBox) Size() int

func (b *CttsBox) Type() string

type DinfBox ¶

type DinfBox struct {
	Dref *DrefBox
}

Data Information Box (dinf - mandatory)

Contained in : Media Information Box (minf) or Meta Box (meta)

Status : decoded

func (b *DinfBox) Encode(w io.Writer) error

func (b *DinfBox) Size() int

func (b *DinfBox) Type() string

type DrefBox ¶

type DrefBox struct {
	Version byte
	Flags   [3]byte
	// contains filtered or unexported fields
}

Data Reference Box (dref - mandatory)

Contained id: Data Information Box (dinf)

Status: not decoded

Defines the location of the media data. If the data for the track is located in the same file it contains nothing useful.

func (b *DrefBox) Encode(w io.Writer) error

func (b *DrefBox) Size() int

func (b *DrefBox) Type() string

type EdtsBox ¶

type EdtsBox struct {
	Elst *ElstBox
}

Edit Box (edts - optional)

Contained in: Track Box ("trak")

Status: decoded

The edit box maps the presentation timeline to the media-time line

func (b *EdtsBox) Dump()

func (b *EdtsBox) Encode(w io.Writer) error

func (b *EdtsBox) Size() int

func (b *EdtsBox) Type() string

type ElstBox ¶

type ElstBox struct {
	Version                             byte
	Flags                               [3]byte
	SegmentDuration, MediaTime          []uint32 // should be uint32/int32 for version 0 and uint64/int32 for version 1
	MediaRateInteger, MediaRateFraction []uint16 // should be int16
}

Edit List Box (elst - optional)

Contained in : Edit Box (edts)

Status: version 0 decoded. version 1 not supported

func (b *ElstBox) Dump()

func (b *ElstBox) Encode(w io.Writer) error

func (b *ElstBox) Size() int

func (b *ElstBox) Type() string

type Fixed16 ¶

type Fixed16 uint16

An 8.8 fixed point number

func (f Fixed16) String() string

type Fixed32 ¶

type Fixed32 uint32

A 16.16 fixed point number

func (f Fixed32) String() string

type FreeBox ¶

type FreeBox struct {
	// contains filtered or unexported fields
}

File Type Box (ftyp - mandatory)

Status: decoded

func (b *FreeBox) Encode(w io.Writer) error

func (b *FreeBox) Size() int

func (b *FreeBox) Type() string

type FtypBox ¶

type FtypBox struct {
	MajorBrand       string
	MinorVersion     []byte
	CompatibleBrands []string
}

File Type Box (ftyp - mandatory)

Status: decoded

func (b *FtypBox) Dump()

func (b *FtypBox) Encode(w io.Writer) error

func (b *FtypBox) Size() int

func (b *FtypBox) Type() string

type HdlrBox ¶

type HdlrBox struct {
	Version     byte
	Flags       [3]byte
	PreDefined  uint32
	HandlerType string
	Name        string
}

Handler Reference Box (hdlr - mandatory)

Contained in: Media Box (mdia) or Meta Box (meta)

Status: decoded

This box describes the type of data contained in the trak.

HandlerType can be : "vide" (video track), "soun" (audio track), "hint" (hint track), "meta" (timed Metadata track), "auxv" (auxiliary video track).

func (b *HdlrBox) Encode(w io.Writer) error

func (b *HdlrBox) Size() int

func (b *HdlrBox) Type() string

type IodsBox ¶

type IodsBox struct {
	// contains filtered or unexported fields
}

Object Descriptor Container Box (iods - optional)

Contained in : Movie Box (‘moov’)

Status: not decoded

func (b *IodsBox) Encode(w io.Writer) error

func (b *IodsBox) Size() int

func (b *IodsBox) Type() string

type MP4 ¶

type MP4 struct {
	Ftyp *FtypBox
	Moov *MoovBox
	Mdat *MdatBox
	// contains filtered or unexported fields
}

A MPEG-4 media

A MPEG-4 media contains three main boxes :

ftyp : the file type box
moov : the movie box (meta-data)
mdat : the media data (chunks and samples)

Other boxes can also be present (pdin, moof, mfra, free, ...), but are not decoded.

func Decode(r io.Reader) (*MP4, error)

func (m *MP4) Boxes() []Box

func (m *MP4) Dump()

func (m *MP4) Encode(w io.Writer) error

type MdatBox ¶

type MdatBox struct {
	ContentSize uint32
	// contains filtered or unexported fields
}

Media Data Box (mdat - optional)

Status: not decoded

The mdat box contains media chunks/samples.

It is not read, only the io.Reader is stored, and will be used to Encode (io.Copy) the box to a io.Writer.

func (b *MdatBox) Encode(w io.Writer) error

func (b *MdatBox) Reader() io.Reader

func (b *MdatBox) Size() int

func (b *MdatBox) Type() string

type MdhdBox ¶

type MdhdBox struct {
	Version          byte
	Flags            [3]byte
	CreationTime     uint32
	ModificationTime uint32
	Timescale        uint32
	Duration         uint32
	Language         uint16
}

Media Header Box (mdhd - mandatory)

Contained in : Media Box (mdia)

Status : only version 0 is decoded. version 1 is not supported

Timescale defines the timescale used for tracks. Language is a ISO-639-2/T language code stored as 1bit padding + [3]int5

func (b *MdhdBox) Dump()

func (b *MdhdBox) Encode(w io.Writer) error

func (b *MdhdBox) Size() int

func (b *MdhdBox) Type() string

type MdiaBox ¶

type MdiaBox struct {
	Mdhd *MdhdBox
	Hdlr *HdlrBox
	Minf *MinfBox
}

Media Box (mdia - mandatory)

Contained in : Track Box (trak)

Status: decoded

Contains all information about the media data.

func (b *MdiaBox) Dump()

func (b *MdiaBox) Encode(w io.Writer) error

func (b *MdiaBox) Size() int

func (b *MdiaBox) Type() string

type MetaBox ¶

type MetaBox struct {
	Version byte
	Flags   [3]byte
	// contains filtered or unexported fields
}

Meta Box (meta - optional)

Status: not decoded

func (b *MetaBox) Encode(w io.Writer) error

func (b *MetaBox) Size() int

func (b *MetaBox) Type() string

type MinfBox ¶

type MinfBox struct {
	Vmhd *VmhdBox
	Smhd *SmhdBox
	Stbl *StblBox
	Dinf *DinfBox
	Hdlr *HdlrBox
}

Media Information Box (minf - mandatory)

Contained in : Media Box (mdia)

Status: partially decoded (hmhd - hint tracks - and nmhd - null media - are ignored)

func (b *MinfBox) Dump()

func (b *MinfBox) Encode(w io.Writer) error

func (b *MinfBox) Size() int

func (b *MinfBox) Type() string

type MoovBox ¶

type MoovBox struct {
	Mvhd *MvhdBox
	Iods *IodsBox
	Trak []*TrakBox
	Udta *UdtaBox
}

Movie Box (moov - mandatory)

Status: partially decoded (anything other than mvhd, iods, trak or udta is ignored)

Contains all meta-data. To be able to stream a file, the moov box should be placed before the mdat box.

func (b *MoovBox) Dump()

func (b *MoovBox) Encode(w io.Writer) error

func (b *MoovBox) Size() int

func (b *MoovBox) Type() string

type MvhdBox ¶

type MvhdBox struct {
	Version          byte
	Flags            [3]byte
	CreationTime     uint32
	ModificationTime uint32
	Timescale        uint32
	Duration         uint32
	NextTrackId      uint32
	Rate             Fixed32
	Volume           Fixed16
	// contains filtered or unexported fields
}

Movie Header Box (mvhd - mandatory)

Contained in : Movie Box (‘moov’)

Status: version 0 is partially decoded. version 1 is not supported

Contains all media information (duration, ...).

Duration is measured in "time units", and timescale defines the number of time units per second.

Only version 0 is decoded.

func (b *MvhdBox) Dump()

func (b *MvhdBox) Encode(w io.Writer) error

func (b *MvhdBox) Size() int

func (b *MvhdBox) Type() string

type SmhdBox ¶

type SmhdBox struct {
	Version byte
	Flags   [3]byte
	Balance uint16 // should be int16
}

Sound Media Header Box (smhd - mandatory for sound tracks)

Contained in : Media Information Box (minf)

Status: decoded

func (b *SmhdBox) Encode(w io.Writer) error

func (b *SmhdBox) Size() int

func (b *SmhdBox) Type() string

type StblBox ¶

type StblBox struct {
	Stsd *StsdBox
	Stts *SttsBox
	Stss *StssBox
	Stsc *StscBox
	Stsz *StszBox
	Stco *StcoBox
	Ctts *CttsBox
}

Sample Table Box (stbl - mandatory)

Contained in : Media Information Box (minf)

Status: partially decoded (anything other than stsd, stts, stsc, stss, stsz, stco, ctts is ignored)

The table contains all information relevant to data samples (times, chunks, sizes, ...)

func (b *StblBox) Dump()

func (b *StblBox) Encode(w io.Writer) error

func (b *StblBox) Size() int

func (b *StblBox) Type() string

type StcoBox ¶

type StcoBox struct {
	Version     byte
	Flags       [3]byte
	ChunkOffset []uint32
}

Chunk Offset Box (stco - mandatory)

Contained in : Sample Table box (stbl)

Status: decoded

This is the 32bits version of the box, the 64bits version (co64) is not decoded.

The table contains the offsets (starting at the beginning of the file) for each chunk of data for the current track. A chunk contains samples, the table defining the allocation of samples to each chunk is stsc.

func (b *StcoBox) Dump()

func (b *StcoBox) Encode(w io.Writer) error

func (b *StcoBox) Size() int

func (b *StcoBox) Type() string

type StscBox ¶

type StscBox struct {
	Version             byte
	Flags               [3]byte
	FirstChunk          []uint32
	SamplesPerChunk     []uint32
	SampleDescriptionID []uint32
}

Sample To Chunk Box (stsc - mandatory)

Contained in : Sample Table box (stbl)

Status: decoded

A chunk contains samples. This table defines to which chunk a sample is associated. Each entry is defined by :

• first chunk : all chunks starting at this index up to the next first chunk have the same sample count/description
• samples per chunk : number of samples in the chunk
• description id : description (see the sample description box - stsd)

func (b *StscBox) Dump()

func (b *StscBox) Encode(w io.Writer) error

func (b *StscBox) Size() int

func (b *StscBox) Type() string

type StsdBox ¶

type StsdBox struct {
	Version byte
	Flags   [3]byte
	// contains filtered or unexported fields
}

Sample Description Box (stsd - manatory)

Contained in : Sample Table box (stbl)

Status: not decoded

This box contains information that describes how the data can be decoded.

func (b *StsdBox) Encode(w io.Writer) error

func (b *StsdBox) Size() int

func (b *StsdBox) Type() string

type StssBox ¶

type StssBox struct {
	Version      byte
	Flags        [3]byte
	SampleNumber []uint32
}

Sync Sample Box (stss - optional)

Contained in : Sample Table box (stbl)

Status: decoded

This lists all sync samples (key frames for video tracks) in the data. If absent, all samples are sync samples.

func (b *StssBox) Dump()

func (b *StssBox) Encode(w io.Writer) error

func (b *StssBox) Size() int

func (b *StssBox) Type() string

type StszBox ¶

type StszBox struct {
	Version           byte
	Flags             [3]byte
	SampleUniformSize uint32
	SampleNumber      uint32
	SampleSize        []uint32
}

Sample Size Box (stsz - mandatory)

Contained in : Sample Table box (stbl)

Status : decoded

For each track, either stsz of the more compact stz2 must be present. stz2 variant is not supported.

This table lists the size of each sample. If all samples have the same size, it can be defined in the SampleUniformSize attribute.

func (b *StszBox) Dump()

func (b *StszBox) Encode(w io.Writer) error

func (b *StszBox) GetSampleSize(i int) uint32

func (b *StszBox) Size() int

func (b *StszBox) Type() string

type SttsBox ¶

type SttsBox struct {
	Version         byte
	Flags           [3]byte
	SampleCount     []uint32
	SampleTimeDelta []uint32
}

Decoding Time to Sample Box (stts - mandatory)

Contained in : Sample Table box (stbl)

Status: decoded

This table contains the duration in time units for each sample.

• sample count : the number of consecutive samples having the same duration
• time delta : duration in time units

func (b *SttsBox) Dump()

func (b *SttsBox) Encode(w io.Writer) error

func (b *SttsBox) GetTimeCode(sample, timescale uint32) time.Duration

func (b *SttsBox) Size() int

func (b *SttsBox) Type() string

type TkhdBox ¶

type TkhdBox struct {
	Version          byte
	Flags            [3]byte
	CreationTime     uint32
	ModificationTime uint32
	TrackId          uint32
	Duration         uint32
	Layer            uint16
	AlternateGroup   uint16 // should be int16
	Volume           Fixed16
	Matrix           []byte
	Width, Height    Fixed32
}

Track Header Box (tkhd - mandatory)

Status : only version 0 is decoded. version 1 is not supported

This box describes the track. Duration is measured in time units (according to the time scale defined in the movie header box).

Volume (relevant for audio tracks) is a fixed point number (8 bits + 8 bits). Full volume is 1.0. Width and Height (relevant for video tracks) are fixed point numbers (16 bits + 16 bits). Video pixels are not necessarily square.

func (b *TkhdBox) Dump()

func (b *TkhdBox) Encode(w io.Writer) error

func (b *TkhdBox) Size() int

func (b *TkhdBox) Type() string

type TrakBox ¶

type TrakBox struct {
	Tkhd *TkhdBox
	Mdia *MdiaBox
	Edts *EdtsBox
}

Track Box (tkhd - mandatory)

Contained in : Movie Box (moov)

A media file can contain one or more tracks.

func (b *TrakBox) Dump()

func (b *TrakBox) Encode(w io.Writer) error

func (b *TrakBox) Size() int

func (b *TrakBox) Type() string

type UdtaBox ¶

type UdtaBox struct {
	Meta *MetaBox
}

User Data Box (udta - optional)

Contained in: Movie Box (moov) or Track Box (trak)

func (b *UdtaBox) Encode(w io.Writer) error

func (b *UdtaBox) Size() int

func (b *UdtaBox) Type() string

type VmhdBox ¶

type VmhdBox struct {
	Version      byte
	Flags        [3]byte
	GraphicsMode uint16
	OpColor      [3]uint16
}

Video Media Header Box (vhmd - mandatory for video tracks)

Contained in : Media Information Box (minf)

Status: decoded

func (b *VmhdBox) Encode(w io.Writer) error

func (b *VmhdBox) Size() int

func (b *VmhdBox) Type() string