h264

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H264

Access Unit (AU) can contain one or multiple NAL Unit:

1. [SEI,] SPS, PPS, IFrame, [IFrame...]
2. BFrame, [BFrame...]
3. IFrame, [IFrame...]

RTP H264

Camera	NALu
EZVIZ C3S	7f, 8f, 28:28:28 -> 5t, 28:28:28 -> 1t, 1t, 1t, 1t
Sonoff GK-200MP2-B	28:28:28 -> 5t, 1t, 1t, 1t
Dahua IPC-K42	7f, 8f, 28:28:28 -> 5t, 28:28:28 -> 1t, 28:28:28 -> 1t
FFmpeg copy	5t, 1t, 1t, 28:28:28 -> 1t, 28:28:28 -> 1t
FFmpeg h264	24 -> 6:5:5:5:5t, 24 -> 1:1:1:1t, 28:28:28 -> 5f, 28:28:28 -> 5f, 28:28:28 -> 5t
FFmpeg resize	6f, 28:28:28 -> 5f, 28... -> 5t, 24 -> 1:1f, 24 -> 1:1t

WebRTC

Video codec	Media string	Device
H.264/baseline!	avc1.42E0xx	Chromecast
H.264/baseline!	avc1.42E0xx	Chrome/Safari WebRTC
H.264/baseline!	avc1.42C0xx	FFmpeg ultrafast
H.264/baseline!	avc1.4240xx	Dahua H264B
H.264/baseline	avc1.4200xx	Chrome WebRTC
H.264/main!	avc1.4D40xx	Chromecast
H.264/main!	avc1.4D40xx	FFmpeg superfast main
H.264/main!	avc1.4D40xx	Dahua H264
H.264/main	avc1.4D00xx	Chrome WebRTC
H.264/high!	avc1.640Cxx	Safari WebRTC
H.264/high	avc1.6400xx	Chromecast
H.264/high	avc1.6400xx	FFmpeg superfast

Useful Links

• RTP Payload Format for H.264 Video
• The H264 Sequence parameter set
• H.264 Video Types (Microsoft)
• Automatic Generation of H.264 Parameter Sets to Recover Video File Fragments
• Chromium sources
• AVC levels
• AVC profiles table
• Supported Media for Google Cast
• Two stream formats, Annex-B, AVCC (H.264) and HVCC (H.265)

Documentation

Index

• Constants
• func EncodeAVC(nals ...[]byte) (avc []byte)
• func GetParameterSet(fmtp string) (sps, pps []byte)
• func GetProfileLevelID(fmtp string) string
• func IsKeyframe(b []byte) bool
• func Join(ps, iframe []byte) []byte
• func NALUType(b []byte) byte
• func RTPDepay(track *streamer.Track) streamer.WrapperFunc
• func RTPPay(mtu uint16) streamer.WrapperFunc
• func RepairAVC(track *streamer.Track) streamer.WrapperFunc
• func SplitAVC(data []byte) [][]byte
• func Types(data []byte) []byte
• type Payloader
  • func (p *Payloader) Payload(mtu uint16, payload []byte) [][]byte

Constants

const (
	NALUTypePFrame = 1 // Coded slice of a non-IDR picture
	NALUTypeIFrame = 5 // Coded slice of an IDR picture
	NALUTypeSEI    = 6 // Supplemental enhancement information (SEI)
	NALUTypeSPS    = 7 // Sequence parameter set
	NALUTypePPS    = 8 // Picture parameter set
	NALUTypeAUD    = 9 // Access unit delimiter
)

const PSMaxSize = 128 // the biggest SPS I've seen is 48 (EZVIZ CS-CV210)

const RTPPacketVersionAVC = 0

Functions

func EncodeAVC

func EncodeAVC(nals ...[]byte) (avc []byte)

func GetParameterSet

func GetParameterSet(fmtp string) (sps, pps []byte)

func GetProfileLevelID

func GetProfileLevelID(fmtp string) string

GetProfileLevelID - get profile from fmtp line Some devices won't play video with high level, so limit max profile and max level. And return some profile even if fmtp line is empty.

func IsKeyframe

func IsKeyframe(b []byte) bool

IsKeyframe - check if any NALU in one AU is Keyframe

func Join

func Join(ps, iframe []byte) []byte

func NALUType

func NALUType(b []byte) byte

func RTPDepay

func RTPDepay(track *streamer.Track) streamer.WrapperFunc

func RTPPay

func RTPPay(mtu uint16) streamer.WrapperFunc

func RepairAVC

func RepairAVC(track *streamer.Track) streamer.WrapperFunc

func SplitAVC

func SplitAVC(data []byte) [][]byte

func Types

func Types(data []byte) []byte

Types

type Payloader

type Payloader struct {
	IsAVC bool
	// contains filtered or unexported fields
}

Payloader payloads H264 packets

func (*Payloader) Payload

func (p *Payloader) Payload(mtu uint16, payload []byte) [][]byte

Payload fragments a H264 packet across one or more byte arrays