When this class was created, we inadvertently set the default to 64 kbit/s for both cases, failing to preserve the previous behavior. This patch restores the old behavior. From what I've been able to dig up, this problem did not affect Opus encoders created internally in the Audio Coding Module. Those have always used the bitrate from the supplied CodecInst. Review-Url: https://codereview.webrtc.org/1942193002 Cr-Commit-Position: refs/heads/master@{#12827}