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How StreamNet™ Makes a Difference 
NetStreams’ patent-pending StreamNet Technology encompasses several protocols, conventions, and technologies to insure the best quality audio and video distribution over TCP/IP. This whitepaper gives a good overview of StreamNet. For more information, contact NetStreams Marketing department at marketing@netstreams.com.
NetStreams' patent-pending StreamNet technology enables manufacturers to deliver a complete audio and video distribution system over TCP/IP networks. StreamNet technology provides an end-to-end all digital solution with A/V signal synchronization, automatic device discovery & configuration, remote access for control, software upgrades and more! All products that carry the StreamNet Connected logo are interoperable, enabling easy integration of audio, video and IT products from multiple manufacturers on the same TCP/IP network. StreamNet provides a stable, easily expandable platform & toolset for future products and new applications. With StreamNet, NetStreams is enabling manufacturers to deliver the future of AV & IT convergence today.If you are interested in liscensing NetStreams' StreamNet technology to develop your own IP-Based entertainment products, please contact NetStreams Business Development department at bizdev@netstreams.com.
Automatic Synchronization of Streams (Time Sync)
One fundamental problem with using TCP/IP to distribute digital audio to multiple zones is the synchronization of playback. Without synchronization, audio can sputter, cut out, or have strong echo effects from room to room, sometimes playing several seconds apart. Simply incorporating a buffer to attempt to synchronize the audio is not enough, resulting in a 50 millisecond delay between any two speakers, which is audible. NetStreams’ patent-pending StreamNet technology provides the solution, by removing the effect of network delays. A “master” is dynamically chosen to serve as the time reference, thereby allowing all devices to share the same concept of time. The sample rate is synchronized using a Voltage Controlled Crystal Oscillator (VCXO) for low jitter. As a result, the maximum delay between any two speakers is reduced to 1 millisecond. StreamNet allows audio in any and all rooms to be synchronized when playing the same source throughout the house, solving the problem of distributing audio over TCP/IP packet-switched streams. Audio synchronization is done automatically, so the only thing you have to do is decide which song(s) you want to playback in which rooms of your facility.
Figure 1: Comparison of Audio signals over TCP/IP:
Listen to Multiple Songs from a StreamNet-Enabled Digital Music Server
Digital Music Servers are a great way to store, catalog, and listen to all of your music. Depending upon the size of the hard disc drive, you can store hours and hours of music on one server. However, with traditional distributed audio systems you can only listen to one song at a time, depending upon the number of discrete output connections on the server. NetStreams has partnered with the leading Digital Music Server brands in the marketplace to incorporate StreamNet technology so you can listen to multiple songs* at the same time from one Digital Music Server over the DigiLinX distributed Audio and Control system. You can even listen to multiple instances of the same song at the same time.
*Depending on the model of the Digital Music Server.
Compatible with Traditional Audio Sources
Your DigiLinX distributed Audio and Control system is also compatible with more traditional audio (and soon video) sources (DVD/CD player, cassette player, XM Satellite Radio, AM/FM tuner, LP player). The StreamNet technology incorporated in the NetStreams MediaLinX™ automatically converts the audio in real time so that it can be streamed over TCP/IP for playback in any room of your DigiLinX system and learns and packetizes its IR commands to be sent over TCP/IP for easy control of the source.
Internet Protocol (IP-Based)
Intelligence and Unprecedented Scalability
The DigiLinX IP-Based distributed Audio and Control system leverages TCP/IP (the same language as the Internet) to deliver audio digitally. The DigiLinX system incorporates a state-of-the-art meshed network architecture in which each product on the network has its own IP address and network intelligence, eliminating the need for costly matrix switches and central controllers. In addition, audio streams are multicast to provide scalability. DigiLinX virtually has no limit on the number of sources or number of rooms you can have in the system, so no matter the size or scale of your facility, DigiLinX can deliver the performance you require.
StreamNet’s suite of communication capablities enable easy system configuration & concrete network reliability:
StreamNet incorporates a suite of communications conventions which reduce the system configuration time required and increase the overall reliability of the network. This section covers Service Discovery, Message Routing, and Status Reporting.
Service Discovery
Every feature or function of the NetStreams DigiLinX IP-Based distributed Audio & Control system is provided by a “service.” There are many types of services – audio renderers, audio sources, general purpose input & outputs (GPIO), user interface, media server proxy, just to name a few. These services ‘advertise’ their existence to the network, broadcasting their name, type, IP-Address(es) and other important information. When StreamNet-enabled devices are plugged into the network, they immediately advertise their capabilities, reducing the need to program the entire system from scratch.
Message Routing
ASCII messages provide the primary method of control and status reporting for StreamNet. Every service has a name and optionally belongs to a “room” and /or some number of “groups”. Messages may be addressed to the service name, room name or group name. Messages may be sent multicast (UDP) or unicast (UDP or TCP) to any or all StreamNet-enabled devices. If required, StreamNet devices will forward messages to ensure delivery to the service(s) addressed.
Status Reporting
StreamNet services output unsolicited reports of their state and changes in state. Reports are in a flexible format that resembles XML. Each report is a list of “variable=value” pairs. Status reports may be sent unicast or multicast. In addition, a TCP client may “register” for status from one or more services and the StreamNet device will aggregate the reports onto the one TCP connection.
High Quality, High Performance Audio
Choose Between Uncompressed, Full Bandwidth Audio and MP3
Your DigiLinX distributed Audio and Control system can handle a wide range of audio sources, from uncompressed, full bandwidth audio to MP3 songs compressed at any sample rate. It is important to note that compressed music (like MP3, WMA, and others) is significantly different from uncompressed music (.WAV - also known as PCM) in sound quality, mainly due to the compression algorithms used.
MP3 is short for MPEG2 Layer 3 — a fancy name for the MP3 audio file format. MP3 audio is a specially formatted and heavily compressed computer file. Depending on sample rate, the audio quality can sound close, but not equal to that of a CD. An uncompressed audio file of 1 minute consumes nearly 11.25 megabytes (MB) of disk space. An MP3 file uses only about 1 MB of disk space for the same minute of audio. This reduction in file size has revolutionized the delivery of music, because it is now easier to transmit music over the internet. A song that would have taken almost an hour to download, depending on the Internet connection, can now be downloaded in about 6 minutes using an MP3 or WMA file. In exchange for a smaller file size, the listener sacrifices 70% of the data that holds what some describe as the 3-D characteristics of the audio data necessary to create staging, imaging, and rich audio texture.
An uncompressed .WAV music file contains all of the data found in a CD, without any compression or loss of data. This offers the listener the highest quality audio available from a CD.
To sample the difference between a compressed (MP-3) music file or an uncompressed (.WAV) music file go to the demo section of our website (www.netstreams.com) and listen for yourself!
Figure 2: MP3 Audio Signal Resolution
Figure 3: Uncompressed (.WAV) Audio Signal Resolution
Pure Digital Signal all the way to the Speakers
Digital Music provides the highest quality of audio since it’s essentially a perfect copy of the digital tape from a recording studio. However, at the amplifier, the digital signal is converted to analog so it can be heard. A fundamental principle in audio is the longer the speaker wire, the more compromised the audio signal becomes, as losses can occur due to speaker wire resistance (regardless of the gauge). Besides losses due to cable resistance, longer cables begin to exhibit a significant reactive component of capacitance and inductance regardless of the wire gauge. When you do distributed audio with longer cable lengths, the signal quality is compromised even more. The DigiLinX system maintains the quality of the signal by allowing the amplifiers to be located at the speaker or in the room, significantly reducing the length of the speaker wire required.
Figure 4: Pure Digital Signal all the way to the Speakers
High Quality Audio Components to Maximize Fidelity
The DigiLinX distributed Audio and Control system incorporates high quality audio components to maximize sound quality. From Burr-Brown® 96kHz / 24-bit D/A and A/D converters to high quality Texas Instruments® and Apogee® Digital Amplifiers, you get the best audio performance possible from your source equipment.
  
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