AEAP Speech to Text / ulaw Codec

Good day! Running into a codec issue with Asterisk version 18.14.0. In Asterisk SIP configuration we use ulaw codec. We tried to use aeap-speech-to-text with setting

codecs=!all,ulaw

in aeap.conf but results in hangup on SpeechStart because in SpeechCreate format check failed: ast_format_cap_iscompatible_format(engine->formats, ast_format_slin) returns AST_FORMAT_CMP_NOT_EQUAL

Then we set codecs=all and requested came to the NodeJS but with codec ‘slin’ which is not supported by Google.

Any suggestions how to use\setup ‘ulaw’ codec for passing to AEAP?

What codec(s) are specified on the channel?

Asterisk, before sending out the initial “setup” request, gets a joint list of codecs between the channel and what’s configured on the speech engine (in this case what you have specified on the in aeap.conf, ulaw), gets the “best” between those and then sends out the request using that.

So if you don’t have ulaw specified on the channel (probably what’s configured on the associated endpoint) then the speech engine can’t find a common codec between them to use.

That was our issue. Thank you!