lib/wire-codecs

VariablesCopy Anchor Link

WIRE_CODECSCopy Anchor Link

const WIRE_CODECS: object;

Defined in: lib/wire-codecs.js:23

Codec names by wire id.

Type DeclarationCopy Anchor Link

1Copy Anchor Link

1: string = 'h264';

2Copy Anchor Link

2: string = 'vp8';

3Copy Anchor Link

3: string = 'vp9';

4Copy Anchor Link

4: string = 'av1';

5Copy Anchor Link

5: string = 'h265';

ENCODER_CODECSCopy Anchor Link

const ENCODER_CODECS: object;

Defined in: lib/wire-codecs.js:26

Encoder wire values and the codec each streams.

Type DeclarationCopy Anchor Link

jpegCopy Anchor Link

jpeg: string = 'jpeg';

h264encCopy Anchor Link

h264enc: string = 'h264';

h264enc-stripedCopy Anchor Link

"h264enc-striped": string = 'h264';

h265encCopy Anchor Link

h265enc: string = 'h265';

vp8encCopy Anchor Link

vp8enc: string = 'vp8';

vp9encCopy Anchor Link

vp9enc: string = 'vp9';

av1encCopy Anchor Link

av1enc: string = 'av1';

H264_ANNEXB_SAMPLECopy Anchor Link

const H264_ANNEXB_SAMPLE: "AAAAAWdCwArd7ARAAAADAEAAAA8DxIngAAAAAWjOD8gAAAABZYiEOiYoDg==" = 'AAAAAWdCwArd7ARAAAADAEAAAA8DxIngAAAAAWjOD8gAAAABZYiEOiYoDg==';

Defined in: lib/wire-codecs.js:449

A 16x16 Baseline key frame in Annex B form, for asking a decoder whether it takes H.264 without an avcC description.

PROBE_CODEC_STRINGSCopy Anchor Link

const PROBE_CODEC_STRINGS: object;

Defined in: lib/wire-codecs.js:512

Type DeclarationCopy Anchor Link

h264Copy Anchor Link

h264: string = 'avc1.42E01E';

h265Copy Anchor Link

h265: string = 'hev1.1.6.L93.B0';

vp8Copy Anchor Link

vp8: string = 'vp8';

vp9Copy Anchor Link

vp9: string = 'vp09.00.31.08';

av1Copy Anchor Link

av1: string = 'av01.0.05M.08';

TEN_BIT_SAMPLESCopy Anchor Link

const TEN_BIT_SAMPLES: object;

Defined in: lib/wire-codecs.js:527

One 10-bit key frame of each format, 320x240 of flat gray, for asking a decoder for a picture rather than for its word: a codec name is its 4:2:0, the name with 444 after it its 4:4:4. An engine can accept a 10-bit configuration and then fail the frame, which only decoding one shows.

PROBE_FULLCOLOR_STRINGSCopy Anchor Link

const PROBE_FULLCOLOR_STRINGS: object;

Defined in: lib/wire-codecs.js:538

The 4:4:4 configurations, at the profiles the encoders emit (VP9 profile 1).

Type DeclarationCopy Anchor Link

h264Copy Anchor Link

h264: string = 'avc1.F4001E';

h265Copy Anchor Link

h265: string = 'hev1.4.10.L93.9E.8';

vp9Copy Anchor Link

vp9: string = 'vp09.01.10.08.03';

FunctionsCopy Anchor Link

wireCodecName()Copy Anchor Link

function wireCodecName(typeByte): string;

Defined in: lib/wire-codecs.js:40

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

string

The codec name; an id no codec has reads as H.264.

wireFrameIsKey()Copy Anchor Link

function wireFrameIsKey(typeByte): boolean;

Defined in: lib/wire-codecs.js:46

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

boolean

Whether the frame is a decode entry point.

codecOfEncoder()Copy Anchor Link

function codecOfEncoder(encoder): string;

Defined in: lib/wire-codecs.js:52

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

string

The codec it streams; an unknown encoder reads as H.264.

codecCarriesFullColor()Copy Anchor Link

function codecCarriesFullColor(codec): boolean;

Defined in: lib/wire-codecs.js:58

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

boolean

Whether the codec can carry 4:4:4 chroma.

codecCarriesTenBit()Copy Anchor Link

function codecCarriesTenBit(codec): boolean;

Defined in: lib/wire-codecs.js:67

Whether a codec has a 10-bit profile the server's encoders emit (H.264 High 10 and High 4:4:4 Predictive, H.265 Main 10 and Main 4:4:4 10, VP9 profiles 2 and 3, AV1).

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

boolean

annexbNals()Copy Anchor Link

function annexbNals(bytes): Uint8Array<ArrayBufferLike>[];

Defined in: lib/wire-codecs.js:74

The NAL units of an Annex-B buffer, each without its start code.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

Uint8Array<ArrayBufferLike>[]

rbspReader()Copy Anchor Link

function rbspReader(
   bytes, 
   offset, 
   limit, 
   raw?
): object;

Defined in: lib/wire-codecs.js:103

A bit reader over an RBSP: bytes from offset with emulation prevention bytes removed, limit bytes at most; raw reads them as they stand, for AV1, which has none.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

object

uCopy Anchor Link

u: (n) => number;

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

number

skipCopy Anchor Link

skip: (n) => void;

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

void

parseAvcCodecFromAnnexB()Copy Anchor Link

function parseAvcCodecFromAnnexB(bytes): string;

Defined in: lib/wire-codecs.js:131

avc1.PPCCLL from the first SPS of an H.264 Annex-B key frame.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

string

null when no SPS is found.

parseHevcCodecFromAnnexB()Copy Anchor Link

function parseHevcCodecFromAnnexB(bytes): string;

Defined in: lib/wire-codecs.js:153

hev1.P.C.TL.CC from the first SPS of an H.265 Annex-B key frame: the general profile, its compatibility flags as the reversed-bit hexadecimal the codecs registration specifies, the tier and level, and the constraint bytes with trailing zero bytes dropped.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

string

null when no SPS is found.

parseAv1CodecFromObus()Copy Anchor Link

function parseAv1CodecFromObus(bytes): string;

Defined in: lib/wire-codecs.js:184

av01.P.LLT.DD from the sequence header of an AV1 temporal unit: the profile, the first operating point's level and tier, and the bit depth its color configuration declares. Every operating point is read past, and the header as it stands, since AV1 has no emulation prevention.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

string

null when no sequence header is found.

parseVp9Profile()Copy Anchor Link

function parseVp9Profile(bytes): number;

Defined in: lib/wire-codecs.js:274

The VP9 profile a frame's uncompressed header declares.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

number

parseVp9BitDepth()Copy Anchor Link

function parseVp9BitDepth(bytes): number;

Defined in: lib/wire-codecs.js:286

The bit depth a VP9 key frame's uncompressed header declares: 8 for profiles 0 and 1, 10 or 12 by the flag that follows the sync code for profiles 2 and 3.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

number

vp9Level()Copy Anchor Link

function vp9Level(
   width, 
   height, 
   fps
): string;

Defined in: lib/wire-codecs.js:305

The lowest VP9 level whose luma sample rate and picture size admit a stream, as the two digits of the codec string.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

string

av1LevelIdx()Copy Anchor Link

function av1LevelIdx(
   width, 
   height, 
   fps
): number;

Defined in: lib/wire-codecs.js:331

The lowest AV1 level admitting a stream, as seq_level_idx; used only when a key frame's sequence header is unreadable. MaxPicSize is its own Annex A limit, far below the product of the axis maxima, since no level admits a picture that is both its widest and its tallest.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

number

h264LevelIdc()Copy Anchor Link

function h264LevelIdc(
   width, 
   height, 
   fps
): string;

Defined in: lib/wire-codecs.js:368

The level_idc, as a two-hex-digit string, an H.264 stream of this geometry declares, floored across the common frame rates like the encoder's own ladder so a rate change moves nothing. Mirrors h264_level in pixelflux codec.rs.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

string

guessAvcCodec()Copy Anchor Link

function guessAvcCodec(
   width, 
   height, 
   is444, 
   fps, 
   chromium
): string;

Defined in: lib/wire-codecs.js:381

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

string

codecStringFor()Copy Anchor Link

function codecStringFor(
   codec, 
   keyframe, 
   width, 
   height, 
   fps, 
   is444, 
   chromium
): string;

Defined in: lib/wire-codecs.js:402

The WebCodecs codec string of a stream, from its key frame where the codec declares it and from the geometry otherwise.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

string

decoderColorSpace()Copy Anchor Link

function decoderColorSpace(codec, fullRange?): VideoColorSpaceInit;

Defined in: lib/wire-codecs.js:434

The color space a decoder is told to assume, which is every session's: no engine reads it out of an H.264 bitstream. Chromium and Firefox both report bt709 at limited range for a stream whose VUI says otherwise, so a full range session rendered without this hint is wrong by up to eight levels a channel, and both honor the hint exactly. VP8 is held to BT.601 whatever the session converted with, the one value its bitstream can name, because Firefox reads that bit and ignores this; VP9 is told BT.709 because Chromium's decoder does not read the matrix from the frame header.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

VideoColorSpaceInit

avcDescription()Copy Anchor Link

function avcDescription(bytes): Uint8Array<ArrayBufferLike>;

Defined in: lib/wire-codecs.js:457

The avcC record of an Annex B key frame's SPS and PPS, for a decoder that takes H.264 only with a description; null when either is missing.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

Uint8Array<ArrayBufferLike>

annexbToAvcc()Copy Anchor Link

function annexbToAvcc(bytes): Uint8Array<ArrayBufferLike>;

Defined in: lib/wire-codecs.js:480

An Annex B access unit as length-prefixed NAL units, the framing an avcC description implies, without its parameter sets and delimiters.

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

Uint8Array<ArrayBufferLike>

sameBytes()Copy Anchor Link

function sameBytes(a, b): boolean;

Defined in: lib/wire-codecs.js:505

ParametersCopy Anchor Link

ReturnsCopy Anchor Link

boolean

Whether both are absent or byte-for-byte equal.