RTCRtpEncodingParameters

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An instance of the WebRTC API's RTCRtpEncodingParameters dictionary describes a single configuration of a codec for an RTCRtpSender. It's used in the RTCRtpSendParameters describing the configuration of an RTP sender's encodings; RTCRtpDecodingParameters is used to describe the configuration of an RTP receiver's encodings.

Properties

active
If true, the described encoding is currently actively being used. That is, for RTP senders, the encoding is currently being used to send data, while for receivers, the encoding is being used to decode received data. The default value is true.
codecPayloadType
When describing a codec for an RTCRtpSender, codecPayloadType is a single 8-bit byte (or octet) specifying the codec to use for sending the stream; the value matches one from the owning RTCRtpParameters object's codecs parameter. This value can only be set when creating the transceiver; after that, this value is read only.
dtx
Only used for an RTCRtpSender whose kind is audio, this property indicates whether or not to use discontinuous transmission (a feature by which a phone is turned off or the microphone muted automatically in the absence of voice activity). The value is taken from the enumerated string type RTCDtxStatus.
maxBitrate
An unsigned long integer indicating the maximum number of bits per second to allow for this encoding. Other parameters may further constrain the bit rate, such as the value of maxFramerate or transport or physical network limitations.
maxFramerate
A double-precision floating-point value specifying the maximum number of frames per second to allow for this encoding.
ptime
An unsigned long integer value indicating the preferred duration of a media packet in milliseconds. This is typically only relevant for audio encodings. The user agent will try to match this as well as it can, but there is no guarantee.
rid
A DOMString which, if set, specifies an RTP stream ID (RID) to be sent using the RID header extension. This parameter cannot be modified using setParameters(). Its value can only be set when the transceiver is first created.
scaleResolutionDownBy
Only used for senders whose track's kind is video, this is a double-precision floating-point value specifying a factor by which to scale down the video during encoding. The default value, 1.0, means that the sent video's size will be the same as the original. A value of 2.0 scales the video frames down by a factor of 2 in each dimension, resulting in a video 1/4 the size of the original. The value must not be less than 1.0 (you can't use this to scale the video up).

Specifications

Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'RTCRtpEncodingParameters' in that specification.
Candidate Recommendation Initial definition.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
RTCRtpEncodingParametersChrome Full support 67Edge ? Firefox Full support 46IE No support NoOpera ? Safari ? WebView Android Full support 67Chrome Android Full support 67Firefox Android Full support 46Opera Android ? Safari iOS ? Samsung Internet Android ?
activeChrome Full support 67Edge ? Firefox Full support 46IE No support NoOpera ? Safari ? WebView Android Full support 67Chrome Android Full support 67Firefox Android Full support 46Opera Android ? Safari iOS ? Samsung Internet Android ?
codecPayloadTypeChrome No support NoEdge ? Firefox No support NoIE No support NoOpera ? Safari ? WebView Android No support NoChrome Android No support NoFirefox Android No support NoOpera Android ? Safari iOS ? Samsung Internet Android ?
dtxChrome No support NoEdge ? Firefox No support NoIE No support NoOpera ? Safari ? WebView Android No support NoChrome Android No support NoFirefox Android No support NoOpera Android ? Safari iOS ? Samsung Internet Android ?
fec
Non-standard
Chrome No support NoEdge No support NoFirefox Full support 46
Notes
Full support 46
Notes
Notes This non-standard property should not be used in production code.
IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoFirefox Android Full support 46
Notes
Full support 46
Notes
Notes This non-standard property should not be used in production code.
Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support No
maxBitrateChrome Full support 67Edge ? Firefox Full support 46IE No support NoOpera ? Safari ? WebView Android Full support 67Chrome Android Full support 67Firefox Android Full support 46Opera Android ? Safari iOS ? Samsung Internet Android ?
maxFramerateChrome No support NoEdge ? Firefox No support NoIE No support NoOpera ? Safari ? WebView Android No support NoChrome Android No support NoFirefox Android No support NoOpera Android ? Safari iOS ? Samsung Internet Android ?
priority
DeprecatedNon-standard
Chrome Full support 67
Notes
Full support 67
Notes
Notes The standard version of this property is RTCRtpSendParameters.priority.
Edge ? Firefox Full support 46
Notes
Full support 46
Notes
Notes The standard version of this property is RTCRtpSendParameters.priority.
IE No support NoOpera ? Safari ? WebView Android Full support 67
Notes
Full support 67
Notes
Notes The standard version of this property is RTCRtpSendParameters.priority.
Chrome Android Full support 67
Notes
Full support 67
Notes
Notes The standard version of this property is RTCRtpSendParameters.priority.
Firefox Android Full support 46
Notes
Full support 46
Notes
Notes The standard version of this property is RTCRtpSendParameters.priority.
Opera Android ? Safari iOS ? Samsung Internet Android ?
ptimeChrome No support NoEdge ? Firefox No support NoIE No support NoOpera ? Safari ? WebView Android No support NoChrome Android No support NoFirefox Android No support NoOpera Android ? Safari iOS ? Samsung Internet Android ?
rid
Non-standard
Chrome No support NoEdge No support NoFirefox Full support 46
Notes
Full support 46
Notes
Notes The standard version of this property is RTCRtpCodecParameters.rid.
IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoFirefox Android Full support 46
Notes
Full support 46
Notes
Notes The standard version of this property is RTCRtpCodecParameters.rid.
Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support No
rtx
Non-standard
Chrome No support NoEdge No support NoFirefox Full support 46
Notes
Full support 46
Notes
Notes This non-standard property should not be used in production code.
IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoFirefox Android Full support 46
Notes
Full support 46
Notes
Notes This non-standard property should not be used in production code.
Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support No
scaleResolutionDownByChrome No support NoEdge ? Firefox Full support 46IE No support NoOpera ? Safari ? WebView Android No support NoChrome Android No support NoFirefox Android Full support 46Opera Android ? Safari iOS ? Samsung Internet Android ?
ssrc
Non-standard
Chrome No support NoEdge No support NoFirefox Full support 46
Notes
Full support 46
Notes
Notes This non-standard property should not be used in production code.
IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoFirefox Android Full support 46
Notes
Full support 46
Notes
Notes This non-standard property should not be used in production code.
Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support No

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.
Deprecated. Not for use in new websites.
Deprecated. Not for use in new websites.
See implementation notes.
See implementation notes.

See also