Class: shaka.codec.Vorbis

Constructor

new Vorbis()

Source:
See:

Members

BLOCK_SIZES_OFFSET_ :number

Offset of the block sizes in the identification header: the packet type, the 6 bytes of 'vorbis', the version (4), the channels (1), the sample rate (4) and the three bitrates (12).
Type:
  • number
Source:

HEADER_COUNT_MINUS_ONE_ :number

The number of headers in the codec configuration of Matroska, minus one: the identification, the comment and the setup headers.
Type:
  • number
Source:

MAX_MODES_ :number

The most modes a stream can have, as the count is 6 bits.
Type:
  • number
Source:

MODE_BITS_ :number

The size of a mode: block flag (1 bit), window type (16), transform type (16) and mapping (8).
Type:
  • number
Source:

MODE_COUNT_BITS_ :number

The size of the field that holds the number of modes, minus one.
Type:
  • number
Source:

PACKET_TYPE_IDENTIFICATION_ :number

The type of an identification header packet.
Type:
  • number
Source:

XIPH_RUN_CONTINUES_ :number

In Xiph lacing a byte of 255 means that the size goes on in the next byte.
Type:
  • number
Source:

Methods

getAdvance(windowSize, nextWindowSize) → {number}

Gets the samples between the start of a packet and the start of the next: a quarter of each of their windows, as consecutive windows overlap by half of the smaller one.
Parameters:
Name Type Description
windowSize number
nextWindowSize number
Source:
Returns:
Type
number

getWindowSize(info, packetnon-null) → {number}

Gets the size of the window of an audio packet.
Parameters:
Name Type Description
info shaka.codec.Vorbis.Info
packet Uint8Array
Source:
Returns:
The size in samples, or 0 if the packet is not audio.
Type
number

parseHeaders(codecPrivatenon-null) → {shaka.codec.Vorbis.Info}

Reads the window sizes and the modes from the headers of a stream.
Parameters:
Name Type Description
codecPrivate Uint8Array The three headers (identification, comment and setup) with the Xiph lacing that Matroska uses: the number of headers minus one, the sizes of all but the last, and the headers.
Source:
Returns:
Type
shaka.codec.Vorbis.Info

parseModes_(setupnon-null) → {Array<number>}

Finds the modes at the end of the setup header. Every mode is 41 bits (a block flag, a window type and a transform type that are 0, and a mapping), and they are followed only by the framing bit, so they can be found from the end, without decoding the codebooks, floors and residues that come before them.
Parameters:
Name Type Description
setup Uint8Array
Source:
Returns:
The block flag of each mode.
Type
Array<number>

splitHeaders_(codecPrivatenon-null) → {Array<!Uint8Array>}

Parameters:
Name Type Description
codecPrivate Uint8Array
Source:
Returns:
The headers, or null if it is not what a Matroska track writes.
Type
Array<!Uint8Array>

Type Definitions

Info

Type:
  • {blockSizes: !Array<number>, modeBlockFlags: !Array<number>, modeBits: number}
Properties:
Name Type Description
blockSizes Array<number> The size in samples of the small and of the large window.
modeBlockFlags Array<number> For each mode, whether it uses the large window (1) or the small (0).
modeBits number The number of bits that write the mode in a packet.
Source: