feat: Add API RTCRtpSender.SetParameters

[karasusan]

This API provides a way to control the streaming quality.

RTCRtpSendParametersRTCRtpSender.GetParameters()
RTCErrorType RTCRtpSender.SetParameters(RTCRtpSendParameters parameter)

Javascript API reference

• RTCRtpSender.getParameters
• RTCRtpSender.setParameters

RTCRtpSendParameters contains an array of RTCRtpEncodingParameters.
RTCRtpEncodingParameters contains parameters to control video quality below.

• active
• maxBitrate
• scaleResolutionDownBy
• maxFramerate

active

This flag can change on/off the streaming.

scaleResolutionDownBy

This parameter is working correctly with only the software encoder.
The factor makes possible to change the frame scale.

maxBitrate

This parameter can change the bitrate dynamically.
Add a note, this value doesn't reflect the result immediately because of the bit rate estimation.

maxFramerate

This parameter is not implemented.

[sindharta]

I think it's better if we have this structure with the same name as the native one.

For the managed version, I think we can use another name,. such as ManagedRTCRtpSendParameters, or something.

[karasusan]

I agree with your suggestion that we have this structure in the managed code with the same name as the native one.

I am considering the name of the class in managed codes, this is the API for developers, the name is the same as the javascript one. I think this is easier to understand.

com.unity.webrtc/Runtime/Scripts/RTPParameters.cs

Line 42 in a40fcde

public class RTCRtpSendParameters

I guess we can change the name of the structure in the native code and the managed one. For example, RTCRtpSendParametersStruct or RTCRtpSendParametersData.

com.unity.webrtc/Plugin~/WebRTCPlugin/WebRTCPlugin.cpp

Lines 468 to 473 in a40fcde

	struct RTCRtpSendParameters
	{
	uint32_t encodingsLength;
	RTCRtpEncodingParameters* encodings;
	char* transactionId;
	};