# video/VP9 & audio/opus codec not supported for simulcast

**URL:** <https://mediasoup.discourse.group/t/video-vp9-audio-opus-codec-not-supported-for-simulcast/5426>\
**Category:** mediasoup libraries\
**Created:** [August 14, 2023, 11:53pm UTC](https://mediasoup.discourse.group/t/video-vp9-audio-opus-codec-not-supported-for-simulcast/5426 "2023-08-14T23:53:42Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![MOSMekawy](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/mosmekawy/32/2289_2.png) [@MOSMekawy](https://mediasoup.discourse.group/u/MOSMekawy)\
**Post date:** [August 14, 2023, 11:53pm UTC](https://mediasoup.discourse.group/t/video-vp9-audio-opus-codec-not-supported-for-simulcast/5426/1 "2023-08-14T23:53:42Z")

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When I try to produce video and audio from client and then creating corresponding producers server side I get these two errors “video/VP9 codec not supported for simulcast” and “audio/opus codec not supported for simulcast”.

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**Author:** ![snnz](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/snnz/32/693_2.png) [@snnz](https://mediasoup.discourse.group/u/snnz)\
**Post date:** [August 15, 2023, 12:15am UTC](https://mediasoup.discourse.group/t/video-vp9-audio-opus-codec-not-supported-for-simulcast/5426/2 "2023-08-15T00:15:43Z")

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You passed more than one encoding to transport.produce() along with VP9 and audio tracks.

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**Author:** ![MOSMekawy](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/mosmekawy/32/2289_2.png) [@MOSMekawy](https://mediasoup.discourse.group/u/MOSMekawy)\
**Post date:** [August 15, 2023, 1:27pm UTC](https://mediasoup.discourse.group/t/video-vp9-audio-opus-codec-not-supported-for-simulcast/5426/3 "2023-08-15T13:27:23Z")

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Sorry, I am new to mediasoup & webrtc, what encodings should I pass to transport.produce() ?

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**Author:** ![MOSMekawy](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/mosmekawy/32/2289_2.png) [@MOSMekawy](https://mediasoup.discourse.group/u/MOSMekawy)\
**Post date:** [August 15, 2023, 1:31pm UTC](https://mediasoup.discourse.group/t/video-vp9-audio-opus-codec-not-supported-for-simulcast/5426/4 "2023-08-15T13:31:35Z")

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I am using one transport for both video and audio. Could this be the issue ?

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**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:** [August 15, 2023, 1:59pm UTC](https://mediasoup.discourse.group/t/video-vp9-audio-opus-codec-not-supported-for-simulcast/5426/5 "2023-08-15T13:59:48Z")

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Read the documentation, please. Those are too basic questions and we write docs for something.

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**Author:** ![MOSMekawy](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/mosmekawy/32/2289_2.png) [@MOSMekawy](https://mediasoup.discourse.group/u/MOSMekawy)\
**Post date:** [August 16, 2023, 4:52pm UTC](https://mediasoup.discourse.group/t/video-vp9-audio-opus-codec-not-supported-for-simulcast/5426/6 "2023-08-16T16:52:07Z")

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I’ve actually came to the forum after I’ve exhausted my other options. When I searched error messages/encodings/codecs and consulted the documentation I found no answers. What I then did was mimic your demo app configs.

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**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:** [August 16, 2023, 5:59pm UTC](https://mediasoup.discourse.group/t/video-vp9-audio-opus-codec-not-supported-for-simulcast/5426/7 "2023-08-16T17:59:17Z")

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Check the RTP Parameters section in the docs and verify what you are sending to transport.produce() in server side.