An instance of the WebRTC API's RTCRtpEncodingParameters dictionary describes a single configuration of a codec for an RTCRtpSender.

This dictionary is used to describe the configuration of an RTP sender's encodings when calling RTCRtpSender.getParameters() or RTCRtpSender.setParameters().

Instance properties


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.

dtx Deprecated Non-standard

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 either enabled or disabled.


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.


A value specifying the maximum number of frames per second to allow for this encoding.


A string indicating the priority of the RTCRtpSender, which may determine how the user agent allocates bandwidth between senders. Allowed values are very-low, low (default), medium, high.


A string 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.


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).


WebRTC: Real-Time Communication in Browsers
# dom-rtcrtpencodingparameters

Browser compatibility

BCD tables only load in the browser

See also