# Simulcast support for vp8

**URL:** <https://react-native-webrtc.discourse.group/t/simulcast-support-for-vp8/397>\
**Category:** General\
**Created:** [December 5, 2019, 11:00am UTC](https://react-native-webrtc.discourse.group/t/simulcast-support-for-vp8/397 "2019-12-05T11:00:50Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![shazzzzzzzz](https://avatars.discourse-cdn.com/v4/letter/s/ed8c4c/32.png) [@shazzzzzzzz](https://react-native-webrtc.discourse.group/u/shazzzzzzzz)\
**Post date:** [December 5, 2019, 11:00am UTC](https://react-native-webrtc.discourse.group/t/simulcast-support-for-vp8/397/1 "2019-12-05T11:00:50Z")

</div>

Hi everyone,

I am planning to implement Simulcast(VP8) on Android & IOS. From what I understand, it could be enabled by setting the encoding parameters in the transceiver. Something like this

```
pc.addTransceiver(track, {
	direction: "sendrecv",
	streams: [stream],
	sendEncodings: [
		{ rid: "h", active: true, maxBitrate: 900000 },
		{ rid: "m", active: true, maxBitrate: 300000, scaleResolutionDownBy: 2 },
		{ rid: "l", active: true, maxBitrate: 100000, scaleResolutionDownBy: 4 }
	]
});

```

Source - [Janus blog](https://www.meetecho.com/blog/simulcast-janus-ssrc/)

However react-native-webrtc does not seems to support _getSenders()_ or _addTransceiver()_ APIs. Can anyone please let me know how do I generate simulcast SDP on react-native-webrtc?

---

<div class="post-metadata">

**Author:** ![saghul](https://yyz2.discourse-cdn.com/free1/user_avatar/react-native-webrtc.discourse.group/saghul/32/4_2.png) [@saghul](https://react-native-webrtc.discourse.group/u/saghul)\
**Post date:** [December 5, 2019, 3:18pm UTC](https://react-native-webrtc.discourse.group/t/simulcast-support-for-vp8/397/2 "2019-12-05T15:18:12Z")

</div>

You need to use the “old” way of doing it by munging the SDP: [http://www.rtcbits.com/2014/09/using-native-webrtc-simulcast-support.html](http://www.rtcbits.com/2014/09/using-native-webrtc-simulcast-support.html)

---

<div class="post-metadata">

**Author:** ![peeratattt](https://yyz2.discourse-cdn.com/free1/user_avatar/react-native-webrtc.discourse.group/peeratattt/32/573_2.png) [@peeratattt](https://react-native-webrtc.discourse.group/u/peeratattt)\
**Post date:** [January 12, 2023, 7:43am UTC](https://react-native-webrtc.discourse.group/t/simulcast-support-for-vp8/397/3 "2023-01-12T07:43:16Z")

</div>

i tried send this not support vp8

```auto
a=rid:h send
a=rid:m send
a=rid:l send
a=simulcast:send h;m;l

```

but i tried send this it support vp8 i don’t know why

```auto
a=rid:l send
a=rid:m send
a=rid:h send
a=simulcast:send l;m;h

```