Video Javascript SDK Release Notes

Added

• Promise support for async SDK methods (non-breaking). The JS SDK now supports modern async/await and promise-based patterns alongside the existing callback-based API. This change is fully backward compatible — all existing callback-based code continues to work without modification. For more information, see this documentation.

• Scalability Mode API. This version adds a new API that allows publishers to explicitly set the target scalability mode, giving developers fine-grained control over the number of spatial (resolution) and temporal (frame rate) layers used during encoding. This enables applications to better balance video quality, adaptability, and resource usage based on their specific needs. For more information, see this documentation. This is a beta feature.

• Performed Android 17 validation. The Vonage Web SDK has been validated on Android 17, confirming smooth operation across Android mobile browsers and WebView applications.

Fixed

• Fixed an issue where, in some cases, subscribing to a VP9 stream failed when the publisher had set videoContentHint to "detail" or "text".

• Fixed a memory leak in audio processing across subscribe/unsubscribe and publish/unpublish cycles that in some cases could lead to unbounded heap growth and audio degradation over time.

• Fixed an issue where in some cases retrying to publish after a failed attempt resulted in a false positive, causing the session.publish callback to report success when the publish had not actually succeeded.

• Fixed an issue where in some cases relay ICE candidates were not included when establishing a connection, which could result in connectivity failures in networks that require TURN relay.

• Fixed an issue where in some cases applying or clearing a video filter after changing the publisher's resolution produced an unexpected zoom effect.

• Fixed an issue where OT.hasMediaProcessorSupport() incorrectly returned false on iOS 26 WKWebView due to Apple's frozen user agent string, blocking the use of Publisher.applyVideoFilter() on affected devices. Additionally, a new asynchronous variant OT.hasMediaProcessorSupport.promise() has been added, which performs a more thorough check of the browser's capabilities and is recommended over the static version for a more accurate and future-proof result.

• Fixed an issue where end-to-end encryption did not work on Safari when the developer tools were opened.

• Fixed an issue introduced in version 2.34.0 where applications enforcing a strict Content Security Policy (CSP) could experience violations when using background blur or background replacement on Safari and Firefox, due to the use of an inline web worker. The inline web worker has been removed, eliminating these CSP violations.

• Fixed an issue in the JS SDK where calling publishVideo(false) after setPreferredResolution() or setPreferredFrameRate() would incorrectly return a constraint error on Firefox and Safari.

Known issues

• Setting a non-default target scalability mode may affect the behaviour of setPreferredResolution() and setPreferredFrameRate() for subscribers. For more information, see the Interaction with subscriber preferred resolution and frame rate note.

Fixed

• Fixed an issue where switching audio input devices (for example, connecting Bluetooth headphones) shortly after session start could trigger an audioAcquisitionProblem that caused complete audio loss for remote participants once the session transitioned to a routed topology.

• Fixed an issue where applications running inside an Android Chrome WebView could not access the precall test or join a video conference.

• Fixed a missing TypeScript definition: the constraints property was not included in the GetUserMediaProperties interface in ot.d.ts, causing a mismatch with the actual runtime behaviour of the SDK.

Fixed

• Fixed an issue where using publisher.setPreferredResolution() in combination with a background filter (blur or replacement) caused the published resolution to change to an unexpected value. The publisher now maintains the intended resolution when a background filter is applied.

• Fixed an issue where toggling video off and back on (publishVideo(false) followed by publishVideo(true)) while a background filter (blur or replacement) was active could briefly expose unfiltered frames to remote participants. The SDK now ensures only filtered frames are sent after video is re-enabled.

• Fixed a change introduced in v2.34 where the TypeScript definition of OT.hasMediaProcessorSupport() incorrectly required a mediaType parameter. The mediaType parameter is now optional, restoring compatibility with existing code that calls OT.hasMediaProcessorSupport() without arguments.

Added

• Added new network condition insights. This version adds new network condition metrics to the client observability feature, providing detailed visibility into network performance and quality indicators. These metrics complement the publisher and subscriber statistics introduced in 2.33.0 and help developers proactively monitor network conditions affecting video quality, diagnose connectivity issues, and make informed decisions about potential adjustments. For more information, see this documentation.

• Added support for background blur and background replacement on Safari and Firefox. This version adds support for background blur and background replacement on Safari and Firefox. This provides feature consistency across all major browsers and devices, addressing customer requests for uniform background effects support across platforms. To check for the availability of required browser APIs, the SDK uses an inline web worker. This inline web worker may trigger Content Security Policy (CSP) violations in applications that enforce a strict CSP — specifically, those that do not include blob: and data: in the worker-src or child-src directives. For more information, see this documentation.

• Added support for Live Captions Translation. This version adds support for Live Captions Translation, which provides real-time subtitle translation during video calls. Each participant can independently select their preferred translation language. This feature supports the full AWS Translate language set. This is a Private Beta feature—to enable Live Captions Translation for your project, contact us. For more information about Live Captions, see this documentation.

Fixed

• This version fixes a timing issue where setting a media processor connector immediately after subscriber creation could fail. The SDK now waits for the stream to be available before applying the connector.

• This version fixes an issue where streams failed to subscribe in sessions with both End-to-end Encryption and Single Peer Connection enabled.

• This version fixes an issue with automatic reconnection handling that could cause unnecessary connection resets during network recovery. Reconnections now occur more reliably without interrupting stable peer connections.

• This version fixes a race condition where calling subscribeToVideo(true) immediately after subscriber initialization could fail if the video track had not yet been received.

• This version fixes issues where packet loss was incorrectly calculated and where audio fallback events were not fired in some situations. These fixes were identified during the implementation of the network condition insights feature, as audio fallback events are one of the inputs used to determine network health. Both fixes result in more accurate and reliable audio fallback behavior.

Requirements

The OpenTok.js library is currently supported in:

• Electron (latest release version)
• Google Chrome (latest release version)
• Google Chrome for Android (latest release version)
• Beta support for Google Chrome for iOS (latest release version)
• Firefox (latest release version)
• Firefox for Android (latest release version)
• Beta support for Firefox for iOS (latest release version)
• Microsoft Edge versions 79+ for Windows and macOS (Chromium-based versions of Edge)
• Safari 11+ on macOS and iOS. For information on video interoperability and other issues, see the Safari browser support page.
• Opera (latest release version)
• Samsung (latest release version)
• WebView Android API level 36+
• WebView on iOS 18.6+

Important: OpenTok.js version 2.16 was the last version to support the Plugin for Internet Explorer. OpenTok.js version 2.16 was deprecated in May 2020 for the Standard environment and June 2020 for the Enterprise environment.

The OpenTok.js library uses port 443. Port 443 must be open on the client network.

Known issues

Browser-specific issues

Safari

• Video quality may appear reduced when canvas content is streamed, due to internal downscaling, device-pixel ratio handling, or Safari's WebRTC encoding. See this WebKit bug.
• End-to-end encryption does not work when developer tools are open in WebKit-based browsers (Safari on macOS/iOS, Chrome on iOS). We are working on a fix.
• Video Javascript SDK 2.27 and later is not supported on Safari 14 and lower.
• New subscribers are inaudible until you bring focus to the browser tab. Switching to the tab restores audio. See this WebKit bug.
• In Safari 17.0+, the video resolution setting is ignored for screen-sharing video. The resulting resolution is always 640x360. See this WebKit bug.
• When calling OT.initPublisher() to initialize a screen-sharing publisher without a user gesture handler, you may receive an InvalidAccessError. This is expected Safari behaviour.
• On iOS 16.4+ with iCloud Private Relay enabled, users may experience disconnects in relayed sessions. See this WebKit bug.
• Audio and video may be lost after an incoming phone call on iOS Safari. After accepting a call and returning to a session, audio and video from the iOS device may drop. See these WebKit bugs: #213853, #219318.
• Audio quality for streams published from Safari on iOS/iPadOS may degrade over time with a crackling or distortion sound. See this WebKit bug.

iOS

• For iOS browser subscribers, the audio level may be incorrect in some cases. We are working on a fix. See this WebKit bug.
• Video flickers when changing device orientation or resizing video on iOS 17+. See this WebKit bug.
• Video is initially displayed at the wrong resolution in a video publisher on iOS 17+, causing a visible flicker as it resizes. See this WebKit regression.
• Emojis unexpectedly appear in videos on iOS 17 due to Apple's Reactions feature. End-users must disable it manually: open Control Center → tap Video Effects → tap Reactions.

Chrome / Chromium

• On Windows with Intel Smart Sound Technology audio drivers, a Publisher may not dispatch an audioInputDeviceChanged event when switching audio input devices. Audio will still route correctly. We are working on a fix.
• Closing the laptop lid while publishing causes the publisher to be destroyed. See this Chromium bug.
• Echo cancellation is disabled with stereo audio input in Chrome 73+. See this Chrome issue.
• Publishing is not supported on http pages (except http://localhost). Pages must be served over https.
• Video can flicker for streams with videoType set to "custom" when video content does not change much. Setting videoContentHint to text or detail mitigates the issue. See the video settings guide.

Firefox

• Setting the frame rate has no effect in Firefox on macOS when using the built-in FaceTime camera. See this Mozilla bug.
• Setting audioBitrate in OT.initPublisher() has no effect in Firefox. See this Mozilla bug.
• On Android 13, Firefox microphone and camera permissions require a device restart to take effect after being set.
• On Android 13, video resolution may not update correctly when switching orientation. See this Mozilla regression.

Android

• On Android 12 and 13, Chrome requires using Media Volume to adjust volume instead of the phone's volume slider. See this Chromium bug.
• In WebView Android, when the app is moved to the background (app switch or incoming call), the publisher video turns off and does not recover when returning to the foreground.

macOS

• Emojis unexpectedly appear in videos on macOS 14 (Sonoma) due to Apple's Reactions feature. To disable: click the green camera icon in the menu bar → deselect Reactions.

General issues

• The accessDialogOpened event may be erroneously dispatched when calling OT.getUserMedia(), even if no access dialog was shown.
• In some cases, when tab-sharing a Google Slides presentation, the video is letterboxed when the publisher aspect ratio is 4:3. This does not occur when screen-sharing the full presentation.
• For some mobile Firefox users, device orientation may corrupt the publisher's video stream. See this Mozilla bug.

Fixed issues

• Fixed a memory leak affecting long-running sessions with multiple participants.
• Fixed a TypeScript definition error where the publisher stats property was incorrectly named transport instead of transportStats.