The Wowza Streaming Engine (WSE) transcoder performs real-time video transcoding and transrating. Using a template system, it matches incoming streams to a customizable template that allows you to control the encoding parameters for transcoded and transrated streams.
The WSE transcoder accepts any inbound video and audio codec. It can output H.263, H.264, H.265, VP8, VP9 video codecs and AAC, MP3, Vorbis, Opus audio codecs. You can create multiple outputs with synchronized keyframes from a single input stream.
The WSE transrater accepts H.264 video codecs and AAC/MP3 audio codecs. It creates outputs with keyframes aligned to the original source, which allows WSE to deliver ABR content to multiple devices over HLS, MPEG-DASH, and RTMP. Single bitrate streaming is supported for all transport protocols.
This article includes software requirements, a list of supported audio and video codecs, hardware acceleration information, and licensing guidance. For help setting up the transcoder on your server, see Set up and Run Transcoder.
Software requirements
The following software is required to use WSE transcoding:
- 64-bit Windows or Linux
- 64-bit Java runtime
- .NET Framework 3.5.1+
- Windows Server requirements:
- Windows Server 2008 R2+
-
Desktop Experience
Supported codecs
Video codecs
WSE transcoder supports the video codecs listed in the table below.
| Codec | Decode | Encode | Notes |
|---|---|---|---|
| H.264 | ✓ | ✓ | Can be delivered over any protocol. |
| HEVC/H.265 | ✓ | ✓ | WSE 4.8.0+; limited player support |
| H.263v2 | — | ✓ |
|
| MPEG-2* | ✓ | — | No GPU-accelerated decoding with EVA |
| MPEG-4 Part 2* | ✓ | — | No GPU-accelerated decoding with EVA |
| VP8† | ✓ | ✓ | WSE 4.5.0+; WebM/DASH only |
| VP9† | ✓ | ✓ | WSE 4.5.0+; WebM/DASH only |
* MPEG-2 and MPEG-4: When using these protocols with EVA, GPU-accelerated decoding is not supported. (The content must be decoded on the CPU.) GPU decoding for these formats is available through the legacy NVIDIA implementation.
† VP8/VP9: See Transcode live streams to WebM for MPEG-DASH playback with Wowza Streaming Engine for implementation details.
Audio codecs
WSE transcoder supports the audio codecs listed in the table below.
| Codec | Decode | Encode | Notes |
|---|---|---|---|
| AAC | ✓ | ✓ |
|
| G.711 | ✓ | — | µ-law and A-law |
| MPEG-1 Layer 1/2 | ✓ | — |
|
| MPEG-1 Layer 3 (MP3) | ✓ | — | Accepted rates: 48000, 44100, 32000 |
| Speex | ✓ | — |
|
| Vorbis* | ✓ | ✓ | WSE 4.5.0+ |
| Opus* | ✓ | ✓ | WSE 4.5.0+ |
* Vorbis/Opus: See Transcode live streams to WebM for MPEG-DASH playback for implementation details.
Hardware acceleration
The WSE transcoder can be configured to take advantage of hardware acceleration using NVIDIA or AMD Xilinx graphics cards. Hardware acceleration is recommended but not required. If hardware acceleration is not configured, the built-in software encoder or decoder will be used.
Note: To determine if hardware acceleration is available on your WSE server, see Verify how Transcoder is running.
Extending the transcoder
The WSE server includes a rich Java API to interact with and control the streaming and transcoding process. The transcoder can be extended by writing custom Java classes that load dynamically at runtime. Transcoder functionality is included in the com.wowza.wms.transcoder.* packages.
Licensing
Perpetual and subscription WSE licenses enable the use of transcoder with each licensed server instance. A single subscription provides 10 concurrent transcoded channels to your pool. Each annual pre-paid instance will increase the pool size by an additional 10 transcoded channels.
If you exceed the number of concurrent transcoded channels available in your pool, you will be charged a monthly overage for each additional concurrent transcoded channel. For questions, please contact our sales team.
The integrated transcoder can decode an unlimited number of inbound live streams and encode an unlimited number of outbound live renditions, subject to CPU/hardware limitations.
