# preferredPayloadType not honored

**URL:** <https://mediasoup.discourse.group/t/preferredpayloadtype-not-honored/1005>\
**Category:** mediasoup libraries\
**Created:** [May 13, 2020, 7:24am UTC](https://mediasoup.discourse.group/t/preferredpayloadtype-not-honored/1005 "2020-05-13T07:24:01Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![ex3ndr](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ex3ndr/32/374_2.png) [@ex3ndr](https://mediasoup.discourse.group/u/ex3ndr)\
**Post date:** [May 13, 2020, 7:24am UTC](https://mediasoup.discourse.group/t/preferredpayloadtype-not-honored/1005/1 "2020-05-13T07:24:01Z")

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I am working on connecting generic webrtc client with mediasoup backend, it works in my prototypes, but i want to reduce number of transports to one and i hit a wall - preferredPayloadType is not honored by consumers. Tried to search the code - it looks like it is not used on native side at all. Am i missing something? Is there a way to force use specific payload type instead of generated one?

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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:** [May 13, 2020, 7:37am UTC](https://mediasoup.discourse.group/t/preferredpayloadtype-not-honored/1005/2 "2020-05-13T07:37:45Z")

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Please describe the topic a bit more. Just in case:

> **[mediasoup :: Communication Between Client and Server](https://mediasoup.org/documentation/v3/communication-between-client-and-server/#consuming-media-in-an-external-endpoint)**
>
> Cutting Edge WebRTC Video Conferencing

There are reasons for using separate PCs (transports) for sending and receiving in mediasoup-client.

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<div class="post-metadata">

**Author:** ![ex3ndr](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ex3ndr/32/374_2.png) [@ex3ndr](https://mediasoup.discourse.group/u/ex3ndr)\
**Post date:** [May 13, 2020, 7:45am UTC](https://mediasoup.discourse.group/t/preferredpayloadtype-not-honored/1005/3 "2020-05-13T07:45:14Z")

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Sorry, but what reasons?

I have everything working on my proof-of-concept with two transports/pc. I just want to have a different logic for consumers - i want browser/app side always to make an offer and i am unable to generate correct answer with payloadType from the offer, it always dynamically generated (100).

I am not sure if this an issue in my case - i just see media flowing between transports, but i can’t hear any sound on both sides.

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<div class="post-metadata">

**Author:** ![ex3ndr](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ex3ndr/32/374_2.png) [@ex3ndr](https://mediasoup.discourse.group/u/ex3ndr)\
**Post date:** [May 13, 2020, 7:50am UTC](https://mediasoup.discourse.group/t/preferredpayloadtype-not-honored/1005/4 "2020-05-13T07:50:52Z")

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Ah! I found the answer: [What are the design limitations leading to separate send/receive transports on the client and can we lift them?](https://mediasoup.discourse.group/t/what-are-the-design-limitations-leading-to-separate-send-receive-transports-on-the-client-and-can-we-lift-them/996/3)

Basicaly mediasoup just forwards packets and can’t (i suppose) change payloadType on consumer side.

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<div class="post-metadata">

**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:** [May 13, 2020, 7:56am UTC](https://mediasoup.discourse.group/t/preferredpayloadtype-not-honored/1005/6 "2020-05-13T07:56:42Z")

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As explained in that topic is more than just rewriting payload types. The limitation is not in mediasoup server but in client side due to SDP.