Version: Wowza Streaming Engine™ 4.9.7+10 build 20260211141237 released February 17, 2026.
Java support: Wowza Streaming Engine 4.9.7 is compiled using Java 17 (OpenJDK Java SE JRE 17.0.12) but can be used with Java versions 17 or 21. For more details, see Java version information.
New features and functionality in Wowza Streaming Engine 4.9.7
10-to-8 bit conversion support for transcoding with MainConcept EVA
With the transition to MainConcept’s EVA, Wowza Streaming Engine 4.9.7 adds support for 10-to-8-bit color depth conversion. This enables workflows where 10-bit source content must be distributed in 8-bit environments, such as legacy playback devices, SDR delivery pipelines, or bandwidth-constrained scenarios.
The conversion process maintains codec compliance while reducing bit depth, with expected trade-offs in color precision and gradient smoothness, and supports output to both HEVC/H.265 8-bit and AVC/H.264 8-bit streams.
10-to-8-bit color-depth conversion is available only when using the EVA-based NVIDIA GPU transcoding pipeline. It's not supported in the legacy NVCUVID/NVENC/CUDA transcoding implementation. For more, see:
Caption support for CMAF HLS packaging workflows and live streams
Wowza Streaming Engine expands its CMAF HLS and CMAF MPEG-DASH packaging workflows with comprehensive support for industry-standard caption formats, including CEA-608, CEA-708, and WebVTT.
This enhancement enables customers to transition to CMAF with full accessibility support, achieving feature parity with legacy HLS caption workflows and introducing closed-caption support for CMAF-packetized MPEG-DASH streams for the first time. These improvements allow you to deliver HEVC/H.265 and 4K video streams through CMAF HLS and CMAF MPEG-DASH while meeting modern accessibility standards and broadcaster requirements. For more details, see:
- About closed captioning in Wowza Streaming Engine
- Configure closed captioning for Wowza Streaming Engine live streams
Improved webhooks support for streaming notifications
Wowza Streaming Engine 4.9.7 introduces several enhancements to webhook functionality. A new retry mechanism automatically resends failed webhook notifications due to temporary network issues or endpoint unavailability, improving delivery reliability. This release also adds support for advanced webhook logging that provides enhanced visibility into event delivery and processing. Finally, you can now configure webhook notifications for server error logs, enabling more proactive monitoring and troubleshooting of system events. For more, see:
- Create webhooks to monitor streaming events in Wowza Streaming Engine
- Create webhooks to monitor streaming events using the Wowza Streaming Engine REST API
- Wowza Streaming Engine Webhooks.json configuration reference
Modernizing NVIDIA GPU transcoding with MainConcept EVA (Beta)
In Wowza Streaming Engine 4.9.7, we are initiating an initial migration to the MainConcept Easy Video API (EVA), laying the foundation for future GPU-accelerated transcoding with improved NVIDIA integration. The new EVA decoding, scaling, and encoding components can be configured now via XML or Wowza Streaming Engine Manager to begin validating the updated pipeline.
Configuration guidelines
To ensure stability while testing this new pipeline, we strongly recommend using a pure EVA workflow for decoding, scaling, and encoding. While the architecture technically supports mixing EVA components with the Default implementation (provided the scaler and encoder match), this hybrid approach may result in reduced performance and is not optimized for production efficiency. Mixing EVA with legacy NVIDIA implementations is not supported.
System requirements
To utilize the EVA architecture, the host server requires the following minimum NVIDIA display drivers. If these requirements are not met, the system will revert to the default software stack:
- Windows x86: Version 572.60
- Linux x86: Version 570.124.04
For setup instructions, see Set up and run Transcoder in Wowza Streaming Engine.
Current architectural limitations
- Performance optimization: As this is an initial integration of the EVA framework, optimization is ongoing. Users may observe a performance reduction of approximately 6-8% compared to the mature legacy implementation.
- Format support: GPU-accelerated decoding via the EVA pipeline is currently not supported for MPEG-2 or MPEG-4 inputs. For the time being, these formats must be decoded on the CPU or via the legacy NVIDIA implementation.
- ARM64 Linux: This architectural update is currently specific to x86 platforms. ARM64 installations continue to utilize CPU transcoding via the MainConcept 16 SDK.
Installation and update considerations for Wowza Streaming Engine 4.9.7
If you're updating to Wowza Streaming Engine 4.9.7 from a base installation of Wowza Streaming Engine 4.9.3 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 4.9.7 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:
- Install – Install and configure Wowza Streaming Engine
- Update – Update your Wowza Streaming Engine installation
Breaking changes in Wowza Streaming Engine 4.9.7
Java version information
Wowza Streaming Engine 4.9.0 - 4.9.7 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 - 4.9.7 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 - 4.9.7, 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 and instructions to copy it from the root of the installer to the Wowza Streaming Engine installation folder. When updating to Wowza Streaming Engine 4.9.0 - 4.9.7 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 - 4.9.7.
While we tested Wowza Streaming Engine 4.8.28 - 4.9.7 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 utilizes custom modules or plugins, we recommend testing them with Wowza Streaming Engine 4.8.28 - 4.9.7 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 - 4.9.7:
- 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 - 4.9.7 that includes these dependencies. For more information, see Manually install and troubleshoot Java on Wowza Streaming Engine.
You can also refer to 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 4.9.7
These changes were made since the release of Wowza Streaming Engine 4.9.6:
- Updated the default CPU transcoder implementation to use MainConcept SDK version 16.0.
- Integrated the MainConcept Easy Video API (EVA) as foundational groundwork for future NVIDIA-accelerated transcoding.
- Added the ability to convert HEVC/H.265 10-bit content to 8-bit for compatibility with SDR workflows and legacy devices.
- Added support to ingest HEVC/H.265 10-bit HDR10 content and transcode it to HEVC/H.265 10-bit without HDR metadata (SDR).
- Added captions support for CEA-608, CEA-708, and WebVTT formats for CMAF HLS and CMAF MPEG-DASH packaging workflows and live streams.
- Improved webhook support for streaming notifications by adding a retry mechanism, advanced webhook logging, and server error logging for system events.
- Added an mpeg4IgnoreMarkerBitErrors property to allow the decoder to bypass marker-bit validation errors in MPEG-4 packets that would otherwise cause exceptions during decoding.
- Resolved an issue where NVIDIA GPUs were not detected when using open source driver variants (version 550 and later).
- Fixed a transcoder crash issue with MainConcept library update.
- Fixed an issue where CEA-708 captions were not displaying due to carriage return (CR) and end of text (ETX) commands not being handled correctly.
- Fixed an issue where master playlists were not being created for audio-only HLS targets, preventing playback.
- Fixed CVE-2025-55752 relative path traversal vulnerability in Apache Tomcat.
- Fixed CVE-2025-55754 for improper neutralization of escape, meta, or control sequences vulnerability in Apache Tomcat.
- Fixed an issue where WebVTT cues generated during HLS playback sometimes disappear prematurely, affecting caption synchronization.
- Fixed an issue where WebRTC connections with Secure Token enabled always included the application instance name in the hash check and streamInfo response, even when it's not specified in the player request.
- Fixed an issue introduced in Wowza Streaming Engine 4.8.13 that caused exceptions during MPEG-4 video decoding and prevented transcoded streams from being playable.
- Fixed an issue where Transcoder overlays were not positioned correctly when using multiple overlays with identical offset values.
- Fixed an issue in Wowza Streaming Engine 4.9.1 where MPEG-TS filter entries for SRT stream files were not displayed in the Manager UI, even though updates to the filters were successfully applied.
- Fixed an issue where thumbnail generation failed on ARM-based images, resulting in empty thumbnail responses and errors such as thumbnailerGetVideoFrame: Response empty.
- Fixed an issue where enabling the <SRTListener> section in VHost.xml after upgrading from Wowza Streaming Engine 4.9.3 (or earlier) to 4.9.5 (and later) caused the server to stop listening on port 1935, preventing RTMP and RTSP streaming.
- Fixed an issue where the Stream Targets page could load slowly or fail due to redundant REST API calls and an unintended global AJAX timeout.
- Fixed an issue in Wowza Streaming Engine 4.9.2 where ingesting SRT streams could cause a thread leak, resulting in continuously increasing JVM thread counts.
- Fixed an issue where VOD captions specified with the wowzacaptionfile query parameter were not processed when the filename contained multiple dots.
- Fixed an issue where unidentified sessions were repeatedly closed without being removed from the session map, causing excessive logging and unnecessary server load.
- Fixed an issue related to Wowza CDN stream targets where network-related problems could cause excessive HTTP connections to remain open and lead to resource exhaustion.
- Fixed an issue with Wowza Streaming Engine license validation affecting the activation of specific non-production and trial license keys.
- Fixed an issue on ARM systems where the updater could cause H.265/HEVC transcoding to fail.
Known issues with Wowza Streaming Engine 4.9.7
For a detailed list of currently known issues, see Known issues with Wowza Streaming Engine.
