I believe the second issue has been fixed here in May: https://github.com/ringcentral/ringcentral-softphone-ts/commit/c8af429182bcd1f100614656f6bb83e0c38177b7
Please try the latest version.
For now we only support 3 codec: PCMU/8000, OPUS/48000/2 and OPUS/16000.
I don’t think uncompress audio is supported. The SDK could support it, but RingCentral SIP server doesn’t support it, so, it won’t work.
To list all the codecs that RingCentral SIP server supports, you can make an inbound call to the softphone SDK and watch the inbound INVITE message. Here is the list as I tested:
a=rtpmap:0 pcmu/8000
a=rtpmap:9 g722/8000
a=rtpmap:18 g729/8000
a=fmtp:18 annexb=no
a=rtpmap:96 ilbc/8000
a=fmtp:96 mode=20
a=rtpmap:8 pcma/8000
a=rtpmap:109 OPUS/16000
a=fmtp:109 useinbandfec=1;usedtx=0;ext32-dred-duration=1000;sprop-ext32-dred-duration=1000
a=rtcp-fb:109 ccm tmmbr
a=rtpmap:111 OPUS/48000/2
a=fmtp:111 useinbandfec=1;usedtx=0;ext32-dred-duration=1000;sprop-ext32-dred-duration=1000
a=rtcp-fb:111 ccm tmmbr
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15