Wowza Streaming Engine 4.8.25 Release Notes

Important: A newer version of Wowza Streaming Engine is available. For more information, see Latest software updates for Wowza Streaming Engine.

Version: Wowza Streaming Engine™ 4.8.25+2 build 20231003151257 released October 4, 2023.

Java support: Wowza Streaming Engine 4.8.25 is built on Java 11 (OpenJDK Java SE JRE 11.0.2) but can be used with Java versions 11 - 12. For more information, see Manually install and troubleshoot Java on Wowza Streaming Engine.

New features and functionality in Wowza Streaming Engine 4.8.25

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. Wowza Streaming Engine 4.8.25 contains enhancements and fixes that improve the functionality of the media server software.

Added SRT improvements

We made several SRT improvements to keep our implementation up to date with the latest from the SRT Alliance. As part of these changes, we added support for multiple audio tracks when streaming using the SRT protocol. For more information, see:

We also updated several Java API methods to access information about SRT sessions and fixed several SRT-related bugs.

Improved AMD Xilinx accelerated transcoding

The Wowza Streaming Engine 4.8.25 release contains additions and improvements to the AMD Xilinx Alveo U30 transcoding workflow. These changes include the following:

  • Changed the default behavior for the AMD Xilinx U30 card to prevent it from overflowing to CPU (MainConcept) transcoding when it's transcoding too many streams. Wowza Streaming Engine versions 4.8.21 to 4.8.24 automatically overflow to use MainConcept transcoding when the U30 card has reached its capacity.
  • Added a new parameter that allows a switch to CPU (MainConcept) transcoding when the AMD Xilinx 30 card is over capacity. For more, see Enable fallback to CPU transcoding.
  • Added support to transcode WebRTC inputs using the AMD Xilinx Alveo U30 card. This feature is only available in preview mode, and you may experience some limitations. For related configuration options, see Allocate resources to use WebRTC with U30.
  • Added support for properties related to the lookahead module to allow better video quality tuning when using the AMD Xilinx Alveo U30 card.
  • Added support for streaming 10-bit color-depth videos that are transcoded with an AMD Xilinx Alveo U30 card.

Installation and update considerations for Wowza Streaming Engine 4.8.25


If you're updating to Wowza Streaming Engine 4.8.25 from a base installation of Wowza Streaming Engine 4.8.17 or earlier, see Updating to Wowza Streaming Engine version 4.8.18 or later.

When using the Wowza Streaming Engine 4.8.25 installer to install 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 4.8.25


Java versions

Wowza Streaming Engine 4.8.18 (or later) is compiled using Java 11 (OpenJDK Java SE JRE 11.0.2) and supports Java versions 11 - 12. Earlier versions of Java aren't supported. 

Important notes about changing the Java version:

  • Wowza Streaming Engine versions before 4.8.18 were compiled using Java 9. If you're updating an earlier installation of Wowza Streaming Engine to version 4.8.18 (or later), you must install OpenJDK Java SE JRE 11.0.2 before running the Wowza Streaming Engine updater. For your convenience, we've provided the OpenJDK Java SE JRE 11.0.2 files as a zip on the Downloads tab of your Wowza account.
  • If your Wowza Streaming Engine workflow uses custom modules or plugins, we recommend testing them with Wowza Streaming Engine 4.8.18 (or later) in a non-production environment before updating your media server software. The following Java modules are included:
    • 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
  • If you have other dependencies, you must install a Java 11 JRE or JDK that includes all your dependencies.

For more information, see Manually install and troubleshoot Java on Wowza Streaming Engine.

Detailed list of changes in Wowza Streaming Engine 4.8.25


Changes since Wowza Streaming Engine 4.8.24

  • Added support for properties related to the lookahead module to allow better video quality tuning when using the AMD Xilinx Alveo U30 card.
  • Added support for streaming 10-bit color-depth videos that are transcoded with an AMD Xilinx Alveo U30 card.
  • Changed the default behavior for the AMD Xilinx U30 card to prevent it from overflowing to CPU (MainConcept) transcoding when it's transcoding too many streams.
  • Added a new parameter that allows a switch to CPU (MainConcept) transcoding when the AMD Xilinx U30 card is over capacity.
  • Added support to transcode WebRTC sources using the AMD Xilinx Alveo U30 card.
  • Added a few new Java API methods to access information about SRT sessions.
  • Added support for multiple audio tracks when streaming using the SRT protocol.
  • Updated Wowza Streaming Engine Transcoder performance benchmarks document.
  • Updated and improved the Garbage Collector for better memory handling.
  • Added HSTS headers to all HTTPS requests for Wowza Streaming Engine Manager.
  • Improved behavior around HTTPStreamerSessions deadlock and memory.
  • Fixed an issue with PAT intervals exceeding 500 ms, setting the new default to 400 ms to match the PAT specification.
  • Fixed an issue with the Xilinx transcoder that caused Wowza Streaming Engine to crash due to high input loads and more than ten simultaneous reconnects.
  • Fixed an issue with the NVENC Transcoder and b-frames that was causing duplicate PTS messages.
  • Fixed an authentication issue with AWS S3 MediaCache sources failing to retrieve content from their respective buckets.
  • Fixed an issue with java.lang.NullPointerException caused by a failed null check when the LiveStreamPacketizers list is empty in the Application.xml.

Known issues with Wowza Streaming Engine 4.8.25


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