Web/API/RTCRtpEncodingParameters

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 BrowsersThe definition of 'RTCRtpEncodingParameters' in that specification.	Candidate Recommendation	Initial definition.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
RTCRtpEncodingParameters	Chrome Full support 67	Edge Full support ≤79	Firefox Full support 46	IE No support No	Opera ?	Safari ?	WebView Android Full support 67	Chrome Android Full support 67	Firefox Android Full support 46	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support 9.0
active	Chrome Full support 67	Edge Full support ≤79	Firefox Full support 46	IE No support No	Opera ?	Safari ?	WebView Android Full support 67	Chrome Android Full support 67	Firefox Android Full support 46	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support 9.0
codecPayloadType	Chrome No support No	Edge No support No	Firefox No support No	IE No support No	Opera ?	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android No support No	Opera Android ?	Safari iOS ?	Samsung Internet Android No support No
dtx	Chrome No support No	Edge No support No	Firefox No support No	IE No support No	Opera ?	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android No support No	Opera Android ?	Safari iOS ?	Samsung Internet Android No support No
fec Non-standard'	Chrome No support No	Edge No support No	Firefox Full support 46 Notes' Full support 46 Notes' Notes' This non-standard property should not be used in production code.	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox 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 No	Safari iOS No support No	Samsung Internet Android No support No
maxBitrate	Chrome Full support 67	Edge Full support ≤79	Firefox Full support 46	IE No support No	Opera ?	Safari ?	WebView Android Full support 67	Chrome Android Full support 67	Firefox Android Full support 46	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support 9.0
maxFramerate	Chrome No support No	Edge No support No	Firefox No support No	IE No support No	Opera ?	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android No support No	Opera Android ?	Safari iOS ?	Samsung Internet Android No support No
priority Deprecated'Non-standard'	Chrome Full support 67 Notes' Full support 67 Notes' Notes' The standard version of this property is RTCRtpSendParameters.priority.	Edge Full support ≤79 Notes' Full support ≤79 Notes' Notes' The standard version of this property is RTCRtpSendParameters.priority.	Firefox Full support 46 Notes' Full support 46 Notes' Notes' The standard version of this property is RTCRtpSendParameters.priority.	IE No support No	Opera ?	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 Full support 9.0 Notes' Full support 9.0 Notes' Notes' The standard version of this property is RTCRtpSendParameters.priority.
ptime	Chrome No support No	Edge No support No	Firefox No support No	IE No support No	Opera ?	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android No support No	Opera Android ?	Safari iOS ?	Samsung Internet Android No support No
rid Non-standard'	Chrome No support No	Edge No support No	Firefox Full support 46 Notes' Full support 46 Notes' Notes' The standard version of this property is RTCRtpCodecParameters.rid.	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 46 Notes' Full support 46 Notes' Notes' The standard version of this property is RTCRtpCodecParameters.rid.	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No
rtx Non-standard'	Chrome No support No	Edge No support No	Firefox Full support 46 Notes' Full support 46 Notes' Notes' This non-standard property should not be used in production code.	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox 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 No	Safari iOS No support No	Samsung Internet Android No support No
scaleResolutionDownBy	Chrome Full support 74	Edge No support No	Firefox Full support 46	IE No support No	Opera ?	Safari ?	WebView Android Full support 74	Chrome Android Full support 74	Firefox Android Full support 46	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support 11.0
ssrc Non-standard'	Chrome No support No	Edge No support No	Firefox Full support 46 Notes' Full support 46 Notes' Notes' This non-standard property should not be used in production code.	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox 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 No	Safari iOS No support No	Samsung 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

• Introduction to the Real-time Transport Protocol (RTP)
• RTCRtpSender, RTCRtpReceiver, and RTCRtpTransceiver

RTCRtpEncodingParameters by Mozilla Contributors is licensed under CC-BY-SA 2.5.