How to Identify and Solve Codec Mismatch Problems in Asterisk

Asterisk Asterisk Support
1

Hi everyone,
I wanted to share a quick technical guide for those who face codec mismatch issues in Asterisk.

Common Symptoms:

  • One-way or no audio

  • Logs show codec mismatch warnings

Troubleshooting Steps:

  1. Check allow= lines in your sip.conf or pjsip.conf

  2. Make sure endpoints (softphones, carriers, trunks) use at least one matching codec

  3. Use rtp set debug on or pjsip set logger on to trace codec negotiation

  4. Check if transcoding is enabled (and licensed for G.729 if used)

Tip: You can run

core show codecs
core show translation

to verify what Asterisk supports.

Hope this helps others facing similar issues — feedback welcome!

2

On Monday 10 November 2025 at 11:51:52, kingasterisk via Asterisk Community
wrote:

I wanted to share a quick technical guide for those who face codec mismatch
issues in Asterisk.

Hope this helps others facing similar issues — feedback welcome!

My feedback is “please put it on a website where it can be found later”.

Antony.

–
Schrödinger’s rule of data integrity: the condition of any backup is unknown
until a restore is attempted.

1 Like
3

Thanks, Antony - appreciate the suggestion!

We’ve already documented this on our internal website for reference, but I wanted to share a quick summary here so others in the community can benefit directly.

4

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