VideoEncoder: configure() method
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Note: This feature is available in Dedicated Web Workers.
The configure()
method of the VideoEncoder
interface changes the state
of the encoder to "configured" and asynchronously prepares the encoder to accept VideoEncoder
s for encoding with the specified parameters. If the encoder doesn't support the specified parameters or can't be initialized for other reasons an error will be reported via the error callback provided to the VideoEncoder
constructor.
If the VideoEncoder
has been previously configured, the new configuration will not be applied until all previous tasks have completed.
Syntax
configure(config)
Parameters
config
-
A dictionary object containing the following members:
codec
-
A string containing a valid codec string. See "codecs" parameter for details on codec string construction.
width
Optional-
An integer representing the width of each output
EncodedVideoChunk
in pixels, before any ratio adjustments. height
Optional-
An integer representing the height of each output
EncodedVideoChunk
in pixels, before any ratio adjustments. displayWidth
Optional-
An integer representing the intended display width of each output
EncodedVideoChunk
in pixels when displayed. displayHeight
Optional-
An integer representing the vertical dimension of each output
EncodedVideoChunk
in pixels when displayed. hardwareAcceleration
-
A hint that configures the hardware acceleration method of this codec. One of:
"no-preference"
"prefer-hardware"
"prefer-software"
bitrate
-
An integer containing the average bitrate of the encoded video in units of bits per second.
framerate
-
An integer containing the expected frame rate in frames per second.
alpha
-
A string indicating whether the alpha component of the
VideoFrame
inputs should be kept or discarded prior to encoding. One of:"discard"
(default)"keep"
scalabilityMode
-
A string containing an encoding scalability mode identifier as defined in WebRTC.
bitrateMode
Optional-
A string containing a bitrate mode. One of:
"constant"
-
The encoder will target constant bitrate.
"variable"
(default)-
The encoder will target a variable bitrate, allowing more space to be used for complex signals and less space for less complex signals.
"quantizer"
-
The encoder will disregard the
bitrate
option and instead it will use codec-specific quantizer values specified for each frame in theoptions
parameter toVideoEncoder.encode()
.
latencyMode
Optional-
A string containing a value that configures the latency behavior of this codec. One of:
"quality"
(default)-
The encoder should optimize for encoding quality.
"realtime"
-
The encoder should optimize for low latency and may even drop frames to honor
framerate
.
Return value
None (undefined
).
Exceptions
TypeError
-
Thrown if the provided
config
is invalid. InvalidStateError
DOMException
-
Thrown if the
state
is"closed"
. NotSupportedError
DOMException
-
Thrown if the provided
config
is valid but the user agent cannot provide a codec that can decode this profile.
Examples
The following example creates a new VideoEncoder
and configures it with some of the available options.
const init = {
output: handleChunk,
error: (e) => {
console.log(e.message);
},
};
let config = {
codec: "vp8",
width: 640,
height: 480,
bitrate: 2_000_000, // 2 Mbps
framerate: 30,
};
let encoder = new VideoEncoder(init);
encoder.configure(config);
Specifications
Specification |
---|
WebCodecs # dom-videoencoder-configure |
Browser compatibility
BCD tables only load in the browser