RTCCodecStats: sdpFmtpLine property
Baseline
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This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2022.
The sdpFmtpLine property of the RTCCodecStats dictionary is a string containing the format-specific parameters of the codec.
These are the values in the "a=fmtp" line in the codec's SDP (if present) after the payload type number (see section 5.8 of the IETF specification for JSEP).
Values
A string containing the format-specific parameters of the codec.
Description
The "a=fmtp" line in the codec's SDP line has the following format, where the payload type (see RTCCodecStats.payloadType) and parameters depend on the codec:
a=fmtp:<payload_type_number> param1=value1; ...; paramN=valueN
For example, the following line would indicate that the "opus" codec, which has a payloadType 99, has the format-specific parameters maxplaybackrate and stereo:
a=fmtp:99 maxplaybackrate=16000; stereo=1;
For this codec, the value in sdpFmtpLine would be maxplaybackrate=16000; stereo=1;.
Specifications
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| Identifiers for WebRTC's Statistics API # dom-rtccodecstats-sdpfmtpline |
Browser compatibility
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sdpFmtpLine in 'codec' stats
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See also
codecs.sdpFmtpLineoption in parameter passed toRTCRtpTransceiver.setCodecPreferences()andRTCRtpSender.setParameters().codecs.sdpFmtpLinein object returned byRTCRtpSender.getParameters()andRTCRtpReceiver.getParameters().