Wowza Streaming Engine 4.9.2 Release Notes

Version: Wowza Streaming Engine™ 4.9.2+6 20250115103439 build released January 15, 2025.

Java support: Wowza Streaming Engine 4.9.2 is compiled using Java 17 (OpenJDK Java SE JRE 17.0.12) but can be used with Java versions 17 or 21. The Wowza Streaming Engine 4.9.2 installer and updater include a Java Runtime Environment (JRE) for Java 21 (OpenJDK Java SE JRE 21.0.3). During updates, we verify that Java 21 is present. If Java 21 isn't detected, the update is canceled, and you can install the JRE 21 provided with the updater before retrying the upgrade. You can manually roll back your Java version if needed. For more details, see Wowza Streaming Engine support for Java.

New features and functionality in Wowza Streaming Engine 4.9.2


Wowza Streaming Engine is a robust, customizable, and scalable media server software that powers reliable streaming of high-quality video and audio to any device, anywhere.

Support for CEA-708 caption conversion to onTextData

Previous versions of Wowza Streaming Engine provided passthrough support for embedded CEA-608/708 captions in live streams. With Wowza Streaming Engine 4.9.2, we expanded this passthrough capability and modernized our closed captioning features.

You can now ingest embedded CEA-708 captions and convert them to onTextData events in outbound live streams. This workflow further allows CEA-708 captions to be translated into WebVTT captions for HLS live streams.

Note: For playback with web-based HTML5 players, iOS, and Safari native players, we recommend using WebVTT captions instead of embedded captions for your live streams. For more, see Configure CEA-608/708 captions for WebVTT output.

We also added support for multiple language tracks in WebVTT captioning outputs and the ability to display non-Latin-based characters for writing systems such as Kanji and Cyrillic. These changes improve the captions display for languages like Chinese, Korean, Arabic, and Russian.

For feature details, configuration information, and upgrade details, see:

Support for AMF onTextData conversion to CEA-708 captions

With Wowza Streaming Engine 4.9.2, we added support for converting AMF onTextData captioning events into CEA-708 captions in outbound live streams.

Note: Not all web-based HTML5 players fully support CEA-708 embedded captions. For example, Wowza Flowplayer doesn't display embedded CEA-708 captions in live streams. For this workflow, we recommend using WebVTT captions when generating your live stream captions. For more, see Configure onTextData captions for WebVTT output.

When producing CEA-708 captions from onTextData events, Wowza Streaming Engine can be configured to create pop-on captions for a cleaner and more polished viewer experience. You can use various new styling and positioning properties from the ANSI/CTA-708-E standard. For example, you can specify anchor points, horizontal and vertical positioning, pen styles, and window styles for captioning windows in your outputs.

Wowza Streaming Engine accommodates multiple language tracks when generating CEA-708 embedded captions in your live streams. We've also added the ability to display non-Latin-based characters for writing systems such as Kanji and Cyrillic. This change improves the captions display for languages like Chinese, Korean, Arabic, and Russian.

For feature details, configuration information, and upgrade details, see:

Installation and update considerations for Wowza Streaming Engine 4.9.2


If you're updating to Wowza Streaming Engine 4.9.2 from a base installation of Wowza Streaming Engine 4.9.1 or earlier, see Updating to Wowza Streaming Engine 4.9.0 and later.

Note: Wowza Streaming Engine 4.8.28 and later doesn't include an updater or installer for macOS.

When using the Wowza Streaming Engine 4.9.2 installer to add a new instance of Wowza Streaming Engine on Windows, you may need to install additional dependencies to ingest SRT MediaCaster streams or use the generic SRT stream targets destination to publish an SRT stream. For more information, see our Ingest and publish an SRT stream guide.

For step-by-step instructions on how to install or update Wowza Streaming Engine, see the following articles:

Breaking changes in Wowza Streaming Engine 4.9.2


Akamai stream targets

Akamai stream targets haven't yet been certified with Wowza Streaming Engine 4.9.0 - 4.9.2. If you're using Wowza Streaming Engine to send live streams to the Akamai HD network for distributed delivery, use a previous version of Wowza Streaming Engine.

Java version information

Wowza Streaming Engine 4.9.0 - 4.9.2 is officially certified, thoroughly tested, and optimized to run seamlessly with the Java 21 JRE. You get the following Java features:

  • Installer details  – Wowza Streaming Engine 4.9.0 - 4.9.2 is compiled using Java 17 (OpenJDK Java SE JRE 17.0.12), but new installations include a JRE for Java 21 (OpenJDK Java SE JRE 21.0.3). You can roll back to Java 17 if needed. Older Java versions (16 and below) are no longer supported and cannot be used with Wowza Streaming Engine 4.9.0 and later.
  • Updater details – When using the updater for Wowza Streaming Engine 4.9.0 - 4.9.2, we verify that the Java 21 Virtual Machine (JVM) is present before completing the upgrade. If Java 21 isn't detected on the machine, the update is canceled with a message containing recommended steps. If you need a new version of Java, the updater includes JRE 21 with instructions explaining how to copy it from the root of the installer to the Wowza Streaming Engine installation folder. When you're updating to Wowza Streaming Engine 4.9.0 - 4.9.2 from a base installation of Wowza Streaming Engine 4.8.28 or earlier, check these considerations.
  • Supported Java versions – If you prefer, you can manually install a different Java version. We support Java versions 17 or 21 with Wowza Streaming Engine 4.9.0 - 4.9.2.

While we tested Wowza Streaming Engine 4.8.28 - 4.9.2 with the Java 21 Runtime Environment (JRE), we didn't recompile it using Java Development Kit (JDK) 21. If you build a custom module using Java 21, it may not work with Wowza Streaming Engine if your source code includes Java 21 features.

Note: New installations of Wowza Streaming Engine 4.8.28 and later deliver generational support for the Z Garbage Collector (ZGC). To use Java 21 with Generational ZGC on Windows, you must be running a 64-bit version of Windows 10 (version 1803 or later) or Windows Server 2019 or later. You also need a 64-bit JVM.

If your Wowza Streaming Engine workflow uses custom modules or plugins, we suggest testing them with Wowza Streaming Engine 4.8.28 - 4.9.2 in a non-production environment before updating your media server software. The following Java modules are included with the JRE and installer for the Wowza Streaming Engine 4.8.28 - 4.9.2:

  • java.base
  • java.datatransfer
  • java.desktop
  • java.instrument
  • java.logging
  • java.management
  • java.management.rmi
  • java.naming
  • java.prefs
  • java.rmi
  • java.scripting
  • java.scripting.jgss
  • java.security.sasl
  • java.sql
  • java.transaction.xa
  • java.xml
  • jdk.crypto.cryptoki
  • jdk.crypto.ec
  • jdk.httpserver
  • jdk.management
  • jdk.management.agent
  • jdk.naming.rmi
  • jdk.unsupported
  • jdk.xml.dom
  • jdk.attach (available with Wowza Streaming Engine 4.8.28 and later)
  • jdk.internal.jvmstat (available with Wowza Streaming Engine 4.8.28 and later)
  • jdk.jcmd (available with Wowza Streaming Engine 4.8.28 and later)
  • jdk.jfr (available with Wowza Streaming Engine 4.8.28 and later)
  • java.net.http (available with Wowza Streaming Engine 4.8.28 and later)

If you have other dependencies, you must install a Java 17 JRE or JDK for Wowza Streaming Engine 4.9.0 - 4.9.2 that includes these dependencies. For more information, see Manually install and troubleshoot Java on Wowza Streaming Engine.

You can also check the Wowza Streaming Engine support for Java page to learn more about the different Java versions we support.

Detailed list of changes in Wowza Streaming Engine 4.9.2


These changes were made since the release of Wowza Streaming Engine 4.9.1:

  • Added support for converting onTextData events to CEA-708 embedded captions in live streams.
  • Added support for converting CEA-708 embedded captions to onTextData events in live streams.
  • Added support for converting CEA-708 embedded captions to WebVTT captions in live streams.
  • Added support for styling and positioning properties when generating CEA-708 captions from onTextData events in live streams.
  • Added support for multiple language tracks when generating CEA-708 embedded captions in live streams.
  • Added support for multiple language tracks in WebVTT captioning outputs for outbound HLS live streams.
  • Added support to display CEA-708 captions for non-Latin-based characters.
  • Updated Wowza Streaming Engine AWS images to use Amazon Linux 2023.
  • Fixed an issue causing advanced Transcoder properties not to apply configurations correctly and to output incorrect values in related logs.

Known issues with Wowza Streaming Engine 4.9.2


For a detailed list of currently known issues, see Known issues with Wowza Streaming Engine.