On a profile with
    <param name="inbound-late-negotiation" value="true"/>
    <param name="inbound-codec-negotiation" value="generous"/>
    <param name="disable-transcoding" value="true"/>
    <param name="inbound-codec-prefs" value="G729,PCMA"/>
    <param name="outbound-codec-prefs" value="G729,PCMA"/>

When someone with codec preference set to PCMA, G729 calls to:

   <extension name="test">
     <condition field="destination_number" expression="^9999$">
       <action application="set" data="ringback=$${us-ring}"/>
       <action application="set" data="instant_ringback=true"/>
       <action application="bridge" data="sofia/internal/1001%10.2.7.206"/>
     </condition>
   </extension>

The bleg INVITE is sent with current OUTBOUND codec prefs not the aleg codec prefs.
This leads to transcoding or other weird stuff like asymmetric codecs in some scenarios.

Attached patch adds support for a_codec_string channel variable that is like ep_codec_string but with original codec preference.
This way one can do:

    <extension name="test">
      <condition field="destination_number" expression="^9999$">
        <action application="info"/>
        <action application="set" data="ringback=$${us-ring}"/>
        <action application="set" data="instant_ringback=true"/>
        <action application="export" data="nolocal:absolute_codec_string=${a_codec_string}"/>
        <action application="bridge" data="sofia/internal/1001%10.2.7.206"/>
      </condition>
    </extension>

And respect aleg codec priority without the need to parse switch_r_sdp in a dialplan.