Guard against malformed server response and fix server codec handling (#312)

@@ -363,15 +363,15 @@ internal constructor(
 
             if (primaryCodecMime != null) {
                 val updatedCodec = primaryCodecMime.mimeTypeToVideoCodec()
-                if (updatedCodec != options.videoCodec) {
+                if (updatedCodec != null && updatedCodec != options.videoCodec) {
                     LKLog.d { "falling back to server selected codec: $updatedCodec" }
-                }
                     options = options.copy(videoCodec = updatedCodec)
 
                     // recompute encodings since bitrates/etc could have changed
                     encodings = computeVideoEncodings((track as LocalVideoTrack).dimensions, options)
                 }
             }
+        }
 
         val transInit = RtpTransceiverInit(
             RtpTransceiver.RtpTransceiverDirection.SEND_ONLY,
@@ -850,6 +850,13 @@ abstract class BaseVideoTrackPublishOptions {
      */
     abstract val scalabilityMode: String?
 
+    /**
+     * Multi-codec Simulcast
+     *
+     * Codecs such as VP9 and AV1 are not supported by all clients. When backupCodec is
+     * set, when an incompatible client attempts to subscribe to the track, LiveKit
+     * will automatically publish a secondary track encoded with the backup codec.
+     */
     abstract val backupCodec: BackupVideoCodec?
 }
 

@@ -16,6 +16,9 @@
 
 package io.livekit.android.room.participant
 
-fun String.mimeTypeToVideoCodec(): String {
-    return split("/")[1].lowercase()
+fun String.mimeTypeToVideoCodec(): String? {
+    return split("/")
+        .takeIf { length > 1 }
+        ?.get(1)
+        ?.lowercase()
 }