# simulcast with PlainRtpTransport and ffmpeg **URL:** \ **Category:** Integration\ **Created:** [April 24, 2020, 7:37am UTC](https://mediasoup.discourse.group/t/simulcast-with-plainrtptransport-and-ffmpeg/863 "2020-04-24T07:37:55Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Codeda](https://avatars.discourse-cdn.com/v4/letter/c/b487fb/32.png) [@Codeda](https://mediasoup.discourse.group/u/Codeda)\ **Post date:** [April 24, 2020, 7:37am UTC](https://mediasoup.discourse.group/t/simulcast-with-plainrtptransport-and-ffmpeg/863/1 "2020-04-24T07:37:56Z")
Is it possible to create stream with simulcast using PlainRtpTransport and ffmpeg? As I understood there will be several `encodings` with different `ssrc` inside `transport.produce`'s `rtpParameters` which will be used in `tee` ffmpeg output. But what about ports? Can I use same rtp and rtcp ports for different qualities with different `ssrc`? ---
**Author:** ![ibc](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ibc/32/1540_2.png) [@ibc](https://mediasoup.discourse.group/u/ibc)\ **Post date:** [April 24, 2020, 9:02am UTC](https://mediasoup.discourse.group/t/simulcast-with-plainrtptransport-and-ffmpeg/863/2 "2020-04-24T09:02:50Z")
You can and you must. But no idea how to do that with ffmpeg. ---
**Author:** ![anovikov1984](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/anovikov1984/32/226_2.png) [@anovikov1984](https://mediasoup.discourse.group/u/anovikov1984)\ **Post date:** [April 27, 2020, 6:21am UTC](https://mediasoup.discourse.group/t/simulcast-with-plainrtptransport-and-ffmpeg/863/3 "2020-04-27T06:21:04Z")
What are other options? Basically our goal is to play out a video file through a mediasoup on server so it comes in 2-3 resolutions through simulcast. I am fine having to rescale and encode 2-3 times. But what are the tools to use if not ffmpeg? Can you give an example of how it’s done? Thanks! ---
**Author:** ![Codeda](https://avatars.discourse-cdn.com/v4/letter/c/b487fb/32.png) [@Codeda](https://mediasoup.discourse.group/u/Codeda)\ **Post date:** [April 27, 2020, 6:43am UTC](https://mediasoup.discourse.group/t/simulcast-with-plainrtptransport-and-ffmpeg/863/4 "2020-04-27T06:43:11Z")
And what `encodings` should we pass to `transport.produce` in `rtpParameters`? Simply with `[{ssrc:22222222},{ssrc:33333333}]` there is no simulcast. Trying different `scalabilityMode` makes no effect or error `cannot use both simulcast and encodings with multiple SVC spatial layers` P.S. When subscribing - consumer.type is `simulcast` but `setPreferredLayers` has no effect for `temporalLayer`, `spatialLayer` or both. Here is an example of my ffmpeg command ```auto ffmpeg -re -i ./input.mp4 -map 0:a:0 -c:a libopus -b:a 128k -ac 2 -ar 48000 \ -c:v libvpx -deadline realtime -cpu-used 4 \ -filter_complex [0:v]split=2[s0][s1];[s0]scale=-2:240[v0];[s1]scale=-2:480[v1] \ -map [v0] -map [v1] -f tee \ [select=a:f=rtp:ssrc=11111111:payload_type=101]rtp://127.0.0.1:10053?rtcpport=11680|\ [select='v\:0':f=rtp:ssrc=22222222:payload_type=102]rtp://127.0.0.1:10831?rtcpport=11521|\ [select='v\:1':f=rtp:ssrc=33333333:payload_type=102]rtp://127.0.0.1:10831?rtcpport=11521 ``` I got only 240p and no 480p. ---
**Author:** ![anovikov1984](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/anovikov1984/32/226_2.png) [@anovikov1984](https://mediasoup.discourse.group/u/anovikov1984)\ **Post date:** [April 27, 2020, 7:44am UTC](https://mediasoup.discourse.group/t/simulcast-with-plainrtptransport-and-ffmpeg/863/5 "2020-04-27T07:44:30Z")
What does “cannot use both simulcast and encodings with multiple SVC spatial layers” mean? We are getting it whenever we use S/L\>1 in scalability mode. T is always 1. I.e. S1T1 works but it’s just 1 mode, S2T1 always results in this error message. What can we be doing wrong? ---
**Author:** ![ibc](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ibc/32/1540_2.png) [@ibc](https://mediasoup.discourse.group/u/ibc)\ **Post date:** [April 27, 2020, 9:55am UTC](https://mediasoup.discourse.group/t/simulcast-with-plainrtptransport-and-ffmpeg/863/6 "2020-04-27T09:55:06Z")
mediasoup does not make magic. Parameters given in server side to `transport.produce()` are supposed to **represent** and **announce** what the media sender endpoint (ffmpeg in your case) will send, and not the other way around (ffmpeg will not magically send whatever you announced to mediasoup in `ProducerOptions`). Does ffmpeg support encoding with temporal layers? No. Why are you assuming there will be then temporal layers? And somehow this topic becomes a pure ffmpeg question, which is not the purpose of this forum. Just a tip: better use gstreamer with complex configurations to simulate simulcast be sending 2-3 stream encodings using same source port for RTP and RTCP. ---
**Author:** ![Codeda](https://avatars.discourse-cdn.com/v4/letter/c/b487fb/32.png) [@Codeda](https://mediasoup.discourse.group/u/Codeda)\ **Post date:** [April 27, 2020, 11:19am UTC](https://mediasoup.discourse.group/t/simulcast-with-plainrtptransport-and-ffmpeg/863/7 "2020-04-27T11:19:34Z")
> [@ibc](#): > > Does ffmpeg support encoding with temporal layers? No. Why are you assuming there will be then temporal layers? We don’t need temporal layers. Spatial is enough. We tried to increase T number only in diagnostics reasons because with changing S/L\>1 there are mediasoup error: cannot use both simulcast and encodings with multiple SVC spatial layers. Basically we don’t need SVC at all. We need simulcast. ---
**Author:** ![ibc](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ibc/32/1540_2.png) [@ibc](https://mediasoup.discourse.group/u/ibc)\ **Post date:** [April 27, 2020, 5:05pm UTC](https://mediasoup.discourse.group/t/simulcast-with-plainrtptransport-and-ffmpeg/863/8 "2020-04-27T17:05:32Z")
I also commented other concerns in my previous response. The last time you just replies to some of my concerns, I spent hours until figuring out that you were using a custom, old and non supported fork of react-native-webrtc. So I won’t do it again.