av

package
v0.0.0-...-639ab39 Latest Latest
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 Go to latest Published: May 16, 2023 License: MIT Imports: 2 Imported by: 0

Documentation

Overview

Package av defines basic interfaces and data structures of container demux/mux and audio encode/decode.

Index

Constants

View Source 
const (
	U8   = SampleFormat(iota + 1) // 8-bit unsigned integer
	S16                           // signed 16-bit integer
	S32                           // signed 32-bit integer
	FLT                           // 32-bit float
	DBL                           // 64-bit float
	U8P                           // 8-bit unsigned integer in planar
	S16P                          // signed 16-bit integer in planar
	S32P                          // signed 32-bit integer in planar
	FLTP                          // 32-bit float in planar
	DBLP                          // 64-bit float in planar
	U32                           // unsigned 32-bit integer
)
View Source 
const (
	CH_FRONT_CENTER = ChannelLayout(1 << iota)
	CH_FRONT_LEFT
	CH_FRONT_RIGHT
	CH_BACK_CENTER
	CH_BACK_LEFT
	CH_BACK_RIGHT
	CH_SIDE_LEFT
	CH_SIDE_RIGHT
	CH_LOW_FREQ
	CH_NR

	CH_MONO     = ChannelLayout(CH_FRONT_CENTER)
	CH_STEREO   = ChannelLayout(CH_FRONT_LEFT | CH_FRONT_RIGHT)
	CH_2_1      = ChannelLayout(CH_STEREO | CH_BACK_CENTER)
	CH_2POINT1  = ChannelLayout(CH_STEREO | CH_LOW_FREQ)
	CH_SURROUND = ChannelLayout(CH_STEREO | CH_FRONT_CENTER)
	CH_3POINT1  = ChannelLayout(CH_SURROUND | CH_LOW_FREQ)
)
View Source 
const (
	// Planar formats
	I420 = PixelFormat(iota + 1) // 4:2:0 8 bit, 12 bpp. Y plane followed by 8 bit 2x2 subsampled U and V planes
	NV12                         // 4:2:0 8 bit, 12 bpp. Y plane followed by an interleaved U/V plane with 2x2 subsampling
	NV21                         // 4:2:0 8 bit, 12 bpp. As NV12 with U and V reversed in the interleaved plane

	// Packed formats
	UYVY // 4:2:2 8-bit, 16 bpp. YUV (Y sample at every pixel, U and V sampled at every second pixel horizontally on each line). A macropixel contains 2 pixels in 1 u_int32.
	//YUY2 // 4:2:2 8-bit, 16 bpp. Same as UYVY but with different component ordering within the u_int32 macropixel.
	YUYV // 4:2:2 8-bit, 16 bpp as for UYVY but with different component ordering within the u_int32 macropixel.

)
View Source 
const (
	Progressive   = ScanningMode(iota + 1)
	InterlacedTFF // Top Field First
	InterlacedBFF // Bottom Field First
)

Variables

View Source 
var (
	H264       = MakeVideoCodecType(avCodecTypeMagic + 1)
	H265       = MakeVideoCodecType(avCodecTypeMagic + 2)
	JPEG       = MakeVideoCodecType(avCodecTypeMagic + 3)
	VP8        = MakeVideoCodecType(avCodecTypeMagic + 4)
	VP9        = MakeVideoCodecType(avCodecTypeMagic + 5)
	AV1        = MakeVideoCodecType(avCodecTypeMagic + 6)
	AAC        = MakeAudioCodecType(avCodecTypeMagic + 1)
	PCM_MULAW  = MakeAudioCodecType(avCodecTypeMagic + 2)
	PCM_ALAW   = MakeAudioCodecType(avCodecTypeMagic + 3)
	SPEEX      = MakeAudioCodecType(avCodecTypeMagic + 4)
	NELLYMOSER = MakeAudioCodecType(avCodecTypeMagic + 5)
	PCM        = MakeAudioCodecType(avCodecTypeMagic + 6)
	OPUS       = MakeAudioCodecType(avCodecTypeMagic + 7)
)

Functions

This section is empty.

Types

type AudioCodecData 

type AudioCodecData interface {
	CodecData
	SampleFormat() SampleFormat                   // audio sample format
	SampleRate() int                              // audio sample rate
	ChannelLayout() ChannelLayout                 // audio channel layout
	PacketDuration([]byte) (time.Duration, error) // get audio compressed packet duration
}

type AudioDecoder 

type AudioDecoder interface {
	Decode([]byte) (bool, AudioFrame, error) // decode one compressed audio packet
	Close()                                  // close decode, free cgo contexts
}

AudioDecoder can decode compressed audio packets into raw audio frame. use ffmpeg.NewAudioDecoder to create it.

type AudioEncoder 

type AudioEncoder interface {
	CodecData() (AudioCodecData, error)   // encoder's codec data can put into container
	Encode(AudioFrame) ([][]byte, error)  // encode raw audio frame into compressed pakcet(s)
	Close()                               // close encoder, free cgo contexts
	SetSampleRate(int) error              // set encoder sample rate
	SetChannelLayout(ChannelLayout) error // set encoder channel layout
	SetSampleFormat(SampleFormat) error   // set encoder sample format
	SetBitrate(int) error                 // set encoder bitrate
	SetOption(string, interface{}) error  // encoder setopt, in ffmpeg is av_opt_set_dict()
	GetOption(string, interface{}) error  // encoder getopt
}

AudioEncoder can encode raw audio frame into compressed audio packets. cgo/ffmpeg inplements AudioEncoder, using ffmpeg.NewAudioEncoder to create it.

type AudioFrame 

type AudioFrame struct {
	SampleFormat  SampleFormat  // audio sample format, e.g: S16,FLTP,...
	ChannelLayout ChannelLayout // audio channel layout, e.g: CH_MONO,CH_STEREO,...
	SampleCount   int           // sample count in this frame
	SampleRate    int           // sample rate
	Data          [][]byte      // data array for planar format len(Data) > 1
}

Raw audio frame.

func (AudioFrame) Concat 

func (self AudioFrame) Concat(in AudioFrame) (out AudioFrame)

Concat two audio frames.

func (AudioFrame) Duration 

func (self AudioFrame) Duration() time.Duration

func (AudioFrame) HasSameFormat 

func (self AudioFrame) HasSameFormat(other AudioFrame) bool

Check this audio frame has same format as other audio frame.

func (AudioFrame) Slice 

func (self AudioFrame) Slice(start int, end int) (out AudioFrame)

Split sample audio sample from this frame.

type ChannelLayout 

type ChannelLayout uint16

Audio channel layout.

func (ChannelLayout) Count 

func (self ChannelLayout) Count() (n int)

func (ChannelLayout) String 

func (self ChannelLayout) String() string

type CodecData 

type CodecData interface {
	Type() CodecType // Video/Audio codec type
}

CodecData is some important bytes for initializing audio/video decoder, can be converted to VideoCodecData or AudioCodecData using: 

codecdata.(AudioCodecData) or codecdata.(VideoCodecData)

for H264, CodecData is AVCDecoderConfigure bytes, includes SPS/PPS.

type CodecType 

type CodecType uint32

Video/Audio codec type. can be H264/AAC/SPEEX/...

func MakeAudioCodecType 

func MakeAudioCodecType(base uint32) (c CodecType)

Make a new audio codec type.

func MakeVideoCodecType 

func MakeVideoCodecType(base uint32) (c CodecType)

Make a new video codec type.

func (CodecType) IsAudio 

func (self CodecType) IsAudio() bool

func (CodecType) IsVideo 

func (self CodecType) IsVideo() bool

func (CodecType) String 

func (self CodecType) String() string

type DemuxCloser 

type DemuxCloser interface {
	Demuxer
	Close() error
}

Demuxer with Close() method

type Demuxer 

type Demuxer interface {
	PacketReader                   // read compressed audio/video packets
	Streams() ([]CodecData, error) // reads the file header, contains video/audio meta infomations
}

Demuxer can read compressed audio/video packets from container formats like MP4/FLV/MPEG-TS.

type MuxCloser 

type MuxCloser interface {
	Muxer
	Close() error
}

Muxer with Close() method

type Muxer 

type Muxer interface {
	WriteHeader([]CodecData) error // write the file header
	PacketWriter                   // write compressed audio/video packets
	WriteTrailer() error           // finish writing file, this func can be called only once
}

Muxer describes the steps of writing compressed audio/video packets into container formats like MP4/FLV/MPEG-TS.

Container formats, rtmp.Conn, and transcode.Muxer implements Muxer interface.

type Packet 

type Packet struct {
	IsKeyFrame      bool          // video packet is key frame
	Idx             int8          // stream index in container format
	CompositionTime time.Duration // packet presentation time minus decode time for H264 B-Frame
	Time            time.Duration // packet decode time
	Duration        time.Duration // packet duration
	Data            []byte        // packet data
}

Packet stores compressed audio/video data.

type PacketReader 

type PacketReader interface {
	ReadPacket() (Packet, error)
}

type PacketWriter 

type PacketWriter interface {
	WritePacket(Packet) error
}

type PixelFormat 

type PixelFormat uint8

Video frame format.

func (PixelFormat) BytesPerPixel 

func (pixFmt PixelFormat) BytesPerPixel() int

BytesPerPixel returns the number of bytes (rounded up) used by a pixel in a given format

func (PixelFormat) HorizontalSubsampleRatio 

func (pixFmt PixelFormat) HorizontalSubsampleRatio() int

HorizontalSubsampleRatio returns the ratio of Y bytes over U or V bytes in a row of pixels

func (PixelFormat) IsPlanar 

func (pixFmt PixelFormat) IsPlanar() bool

IsPlanar return true if this pixel format is planar.

func (PixelFormat) String 

func (pixFmt PixelFormat) String() string

func (PixelFormat) VerticalSubsampleRatio 

func (pixFmt PixelFormat) VerticalSubsampleRatio() int

VerticalSubsampleRatio returns the ratio of Y bytes over U or V bytes in a column of pixels

type SampleFormat 

type SampleFormat uint8

Audio sample format.

func (SampleFormat) BytesPerSample 

func (self SampleFormat) BytesPerSample() int

func (SampleFormat) IsPlanar 

func (self SampleFormat) IsPlanar() bool

Check if this sample format is in planar.

func (SampleFormat) String 

func (self SampleFormat) String() string

type ScanningMode 

type ScanningMode uint8

Video scanning mode.

func (ScanningMode) String 

func (s ScanningMode) String() string

type VideoCodecData 

type VideoCodecData interface {
	CodecData
	Width() int  // Video width
	Height() int // Video height
}

Source Files

View all Source files

Directories

Path Synopsis
Package pktque provides packet Filter interface and structures used by other components.
 Package pktque provides packet Filter interface and structures used by other components.
Packege pubsub implements publisher-subscribers model used in multi-channel streaming.
 Packege pubsub implements publisher-subscribers model used in multi-channel streaming.
Package transcoder implements Transcoder based on Muxer/Demuxer and AudioEncoder/AudioDecoder interface.
 Package transcoder implements Transcoder based on Muxer/Demuxer and AudioEncoder/AudioDecoder interface.

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