Add Messaging, Voice, and Authentication to your apps with Vonage Communications APIs
Visit the Vonage API Developer PortalUse the OpenTok audio fallback API to dynamically prioritize audio in response to network quality.
Audio fallback keeps your calls running for all participants, regardless of connection issues or poor network conditions by temporarily disabling video for the affected participant. OpenTok’s audio fallback capability reacts to network conditions in real time, ensuring participants won’t drop out when faced with poor coverage. When conditions improve, a video stream is reestablished through our video-recovery capability.
The publisher and subscriber audio fallback features combine to provide optimal call quality. A single subscriber can fall back to audio-only (if only the subscriber's conditions warrant it) or a publisher can fall back to audio-only for poor network conditions.
When the publisher and subscribe audio fallback features are enabled, the SDK dispatches events to indicate changing quality conditions. You can use these events to trigger notifications in the client, or the SDK can display the default UI notifications.
The subscriber audio fallback feature improves call quality by automatically turning off incoming video video streams resulting in an audio-only mode in response to deteriorating network conditions on the subscriber-side. Other clients will continue to receive video regardless of the subscriber's network conditions. This feature is handled through the OpenTok Media Router and is only available in routed sessions. See the session creation docs to understand the distinction between routed and relayed sessions.
The publisher audio fallback feature improves call quality by having a publisher switch to audio-only mode when the publishing client's network conditions cannot support video. The publisher will resume video when network conditions improve.
The publisher audio fallback feature is supported in both relayed and routed sessions (see The OpenTok Media Router and media modes).
The publisher audio fallback features includes enhancements to monitor the bandwidth and congestion of a published stream. The publisher will prioritize audio communication and fallback to audio when the bandwidth congestion cannot support video communications.
With the publisher audio fallback feature, the publishing client receives quality feedback (on packet loss, bandwidth, and congestion) from the subscriber (in a relayed session) or the OpenTok Media Router (in a routed session).
You can enable and disable audio fallback when you publish a stream:
The client SDKs include events for publisher and subscriber audio fallback. These events indicate when the publisher or subscriber video is enabled or disabled, and when there is a warning for the video being disabled, due to audio fallback (and video recovery).
