Pin exact audio and video codecs + set params for h264 codec

src/lib.rs

@@ -382,7 +382,22 @@ fn handle_jsep(
             let offer = sdp::Sdp::parse(&CString::new(sdp)?)?;
             janus_verb!("[CONFERENCE] offer: {:?}", offer);
 
-            let answer = answer_sdp!(offer);
+            let mut answer = answer_sdp!(
+                offer,
+                sdp::OfferAnswerParameters::AudioCodec,
+                sdp::AudioCodec::Opus.to_cstr().as_ptr(),
+                sdp::OfferAnswerParameters::VideoCodec,
+                sdp::VideoCodec::H264.to_cstr().as_ptr()
+            );
+            let video_payload_type = answer.get_payload_type(sdp::VideoCodec::H264.to_cstr());
+            if let Some(pt) = video_payload_type {
+                let settings = CString::new(format!(
+                    "{} profile-level-id=42e01f; packetization-mode=1",
+                    pt
+                ))?;
+                answer.add_attribute(pt, c_str!("fmtp"), &settings);
+            }
+
             janus_verb!("[CONFERENCE] answer: {:?}", answer);
 
             let answer = answer.to_glibstring().to_string_lossy().to_string();