The Helix™ DNA Client


The Helix™ DNA Client is the universal playback engine designed to support the decode and playback of any data type desired. It is interoperable with all Helix certified products including the Helix DNA Server and Helix DNA Producer and can be ported to any operating system and used with any processor. The Helix DNA Client is designed as an open, comprehensive platform that enables playback of digital media products and applications for any format, operating system, or device. The Helix DNA Client supports any audio or video codec through well-defined file format and decoder APIs. By using the Helix DNA Client as the core media engine inside or alongside your own products, developers can create any number of powerful applications on the widest range of devices, including mobile phones, set top boxes, home gateways, personal music players, personal computers, DNA Client Diagramand more.


Standards-Based A/V Data Type Support

The Helix DNA Client contains support in source code form for the following data types:

  • MP3
  • H.263
  • SMIL
  • JPEG
  • GIF
  • PNG
  • RealPix
  • PCM
  • WAV

In addition, binary-only support is provided for:

  • RealAudio G2
  • RealAudio 8
  • RealVideo G2
  • RealVideo 7
  • RealVideo 8
  • RealVideo 9

Additionally, RealNetworks is working with The Foundation on support for the Ogg Vorbis format.

In the future, RealNetworks may be able to release support for:

  • AVI
  • AU
  • RealText

RTSP/RTP/RTCP/SDP Network Playback

The Helix DNA Client supports a number of industry standards for real-time streaming of multimedia content, including:

  • The Real Time Streaming Protocol (RTSP), a multimedia presentation control protocol
  • The Real Time Transport Protocol (RTP), a packet format for multimedia data streams
  • The RTP Control Protocol (RTCP), to monitor the quality of service and transfer participant information in an ongoing session
  • The Session Description Protocol (SDP), to describe multimedia sessions to support session announcement, invitation, and other forms of initiation

You can learn more about these standards at the RTSP site.

The Helix DNA Client supports streaming over both TCP and UDP, to provide support for a wide range of usage models.

Local File Playback

The Helix DNA Client supports the playback of local files, in addition to Internet streams, for supported file formats. Such formats include 3GPP (source code provided) and RealMedia (binary-only).

Audio and Video Services

The Helix DNA Client includes modules to support:

  • audio mixing
  • resampling
  • volume handling and management
  • windowing and alphablending of multiple visual data types

Data Type Interfaces

The Helix DNA Client offers APIs for developers to create plug-ins to support their favorite file formats or client renderers. Renderers are designed to play specific datatypes, such as audio and video via codecs. Hence, the Helix DNA Client will stream and play any media type with an implemented renderer and file format plug-ins.

Proxy Support

The Helix DNA Client supports proxies for both the HTTP and RTSP protocols. Each type of proxy can be auto-configured, including support for Web Proxy Auto Detect. Authentication support is also available for both types of proxy.


The Helix DNA Client includes TurboPlay(TM) technology. Through TurboPlay, broadband PC users get near-instant playback of streaming audio and video. TurboPlay dramatically reduces the time it takes to load or "buffer" a clip prior to playback by intelligently utilizing available bandwidth on a broadband connection, typically achieving more than five times the speed of previous streaming systems.


The Helix DNA Client is available through both the RealNetworks Community Source License and the RealNetworks Public Source License. More information on these licenses can be found on our licensing page. Separately, RealNetworks also offers a free software development kit that will enable you to write applications to the RealPlayer.

The RCSL includes options for licensing the RealAudio and RealVideo codecs for distribution. RPSL licensees cannot distribute RealAudio and RealVideo but are welcome to point users back to this site where they can obtain those codecs themselves for personal use.

Getting the Source

To get the source code to the Helix DNA Client, you must first register for the site and get an account. Then, you will be able to click links to agree to either the RPSL or the RCSL. Once you have agreed to the license, click on the Projects tab, and you will be able to download the source code!

You can also learn more about the general client architecture on the Helix DNA Client Development home page.