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Audio over IP…Are you ready for the Remote Broadcast revolution?
Audio over IP is the next big remote broadcast
revolution and offers opportunities to deliver near real time, high
quality audio from remote locations over the internet including
DSL, Wi-Fi (802.11x,) cable modems, high speed data cell phones
and satellite IP networks.
At Tieline, we have been quietly working
on adding audio over IP functionality to our G3 Commander and i-Mix
platform to make them the world’s first POTS, ISDN, GSM and
IP-capable codecs.
In this text we explore ways of preparing
your studio and remote toolkit to take advantage of the Internet
for high quality, low cost remotes.
1. Tieline IP Codec Features at a Glance:
Tieline’s IP software module has been
designed to suit variable Internet broadcasting conditions and offers
a range of configurable options to get the best results from wired
and wireless networks. Connections in the field are mostly automatic
for non-technical users and the codec can also be pre-configured
by the studio engineer before sending it out into the field. It
can even be fully remote controlled from the studio.
Tieline’s implementation
also features:
- A range of algorithms offering broadcast
quality 7.5kHz mono as low as 9.6Kbps, 15kHz mono at 24Kbps, 15kHz
stereo at 56Kbps and up to 20kHz stereo at 128Kbps. These are
suitable for broadband internet broadcasting. (Algorithms include
Tieline Voice G3, Tieline Music, G.711, G.722 and Mpeg Layer 2.)
- Auto configuration of the IP
address, subnet and default gateway from DHCP
networks which allows connection of a remote field
codec to a wired DSL or Wi-Fi hotspot and dial back to the studio
in actually.
- Manual configuration of the IP address,
gateway, subnet and ports is also possible for proprietary and
highly secure networks.
- Uncompressed (Linear) 15-20kHz audio.
Suitable for high quality Studio-to-Transmitter links (STL), Studio-to-Studio
and high end applications.
- Configurable buffering combined with
manual bit rate renegotiation to maximize link stability and audio
quality.
- Auto configuration of the remote codec
from the dialing codec. (I.e. the remote codec will recognize
the settings you have created in the dialing codec and auto reconfigure).
- Remote control of your talent’s
audio input level from the studio means you receive optimal levels
without the need for technical support on site.
- Optional Automatic failover to POTS telephone
line or ISDN or GSM.
- Simultaneous broadcasting over IP and
your choice of POTS, ISDN or GSM.
- Multicasting is under development and
will be released in 2006.
2. Configuring your
Studio for IP broadcasts.
Preparing your studio to receive IP
calls from your remote codec is similar to ordering a POTS or ISDN
service. If you're not a network IT professional….you should
consider hiring one to install and configure the service properly
before you connect your codec.
3. The Internet:
Let’s start
with the basics. For best results, we recommend a high speed internet
connection. It comes in many flavors such as DSL, ADSL, Cable and
Satellite. For the studio, we recommend a wired high speed service
with a downlink of at least 128Kbps and an uplink speed of at least
64Kbps. Faster installations often provide greater reliability and
more broadcasting options. Be wary of wireless networks in the studio
which are prone to interference from many different environmental
elements over which the codec will have no control.
For Studio-to-Transmitter links where uncompressed
(linear) or high bit rate audio is required, we recommend you consider
purchasing a priority data service and a dedicated link from your
ISP to guarantee link stability and data integrity. The ISP can
tag your data packets to ensure they receive priority over other
network traffic. Uncompressed 20kHz Stereo STL links will require
2.5 megabit for successful transmission of just the audio. If you
have additional network traffic, you will need more bandwidth.
4. A Permanent Public IP Address:
Next you need to purchase or obtain a permanent Public IP address
(often called Static Public IP and usually available from a reputable
ISP or professional IT organization).
A public IP address is a permanent address
for your Internet connection. Instead of street names and house
numbers, it's a series of numbers and dots (called a dotted quad)
that allows computers to locate and talk to one another on the Internet,
similar to the way in which we use phone numbers to locate and talk
to people.
A public IP address allows you to host your
own services on your broadband connection without needing to notify
everyone each time you reconnect to the Internet.
It's worth noting that with a standard “always
connected” broadband service, your ISP dynamically assigns
you a public IP address. This IP address can be changed every time
you connect to the Internet and even while you are connected which
is why you cannot reliably use a dynamically assigned IP address
for remote broadcasts and should consider obtaining a permanent
public IP address.
5. Network Address Translation
We recommend you hire the services of your ISP or IT professional
to "install" the public IP address and perform the Network
Address Translation (NAT) between the public Internet and your private
Local Area Network (LAN).
The best way to explain NAT is to use a
simple example. A standard PBX telephone system allows people to
call you on a single public telephone number and performs the translation
and routing of the public number into a particular private PBX extension.
Similarly, in order to receive an IP call from a remote codec over
the public Internet, the same network address translation principle
applies. NAT allows a single device, such as a broadband router,
to act as an agent between the public Internet and a local private
LAN.
NAT devices such as broadband routers also
act as a simple firewall preventing unwanted traffic. Depending
on how your firewall is configured, your system may require Port
Forwarding to enable the call from the remote codec to be received
by your studio codec. The Tieline default port is 6000. However
this can be changed in the software if you have other applications
or devices on your network that are routed to this port number.
6. Installing the Studio Codec:
Once you have the Static IP address installed and your IP professional
on hand to perform the network address translation, you can go ahead
and install the codec. (I.e. connect the LAN port on the rear of
the codec to your LAN network port.)
A DHCP network (Dynamic Host Configuration
Protocol) is a fancy name for a network host that automatically
assigns an IP address (or private extension number if you think
back to the PBX example) to any piece of equipment that is connected
to your LAN. It will also configure the subnet mask and default
gateway in the codec. If you have a DHCP enabled network then the
minute you plug in your Tieline codec, it will be assigned a number
that looks much like 192.168.X.X or 10.X.X.X or even 172.16.X.X.
This is the private extension number of the codec on your LAN. Your
public IP address should be routed to this private IP address through
your NAT configuration.
If your installation is only temporary,
(i.e. for 1 broadcast or a short period of time) then you should
be able to rely on the DHCP auto assigned IP address. However, be
aware that as soon as you cycle the power on the codec, a new IP
address is likely to be assigned by your network to the codec. The
NAT translation will still route the incoming call to the original
private IP address and you will not get a connection.
Therefore, for permanent or long term installations
we recommend that your IT professional configures your network to
assign the same private IP address to the codec every time the power
is cycled. Alternatively you can assign a static private IP address
to the codec and configure your local network to obtain the IP address
from the codec.
One last important point: Normally, you
will not be able to initiate an outbound call from the studio codec
over the Internet to the remote codec.
Think of the PBX example again. You can
dial from a private extension number to a public number, but you
cannot dial from a private number to another private number because
the public network will not recognize the call without PBX translation.
Similarly your remote field codec will be assigned a private LAN
IP address from which you can initiate a call to your public IP
address at the Studio and NAT will successfully route your call
to the private IP address of the studio codec, but you will not
work the other way.
Tieline is currently developing a server
system which will enable two codecs with private addresses to find
each other. In principal, if both codecs are assigned a private
IP address and you do not have access to a public IP address and
translation installation, then our host server will provide the
translation and connection. This development is scheduled for release
in 2006.
7. Getting into the Field.
OK we have the studio configured and ready
to go. Now what do we need to get out into field?
The new IP software has been integrated into the Tieline Commander
G3 field codec and the i-Mix G3 codec. You can go completely wireless
with a portable battery
module installed and a Wi-Fi bridge connected to the
LAN port of the codec or if the venue has power and a wired LAN
port available then you can plug directly into them.
8. Wired networks:
If the venue or remote broadcast site has
a DHCP LAN which can access a broadband Internet service, then all
you need to do is connect the codec to the LAN port, dial the studio
and you’re on the air. It’s that simple.
Even if the venue does not have a corporate
LAN, many of the latest DSL routers have the ability to assign an
IP address to equipment and you can attach the codec to a LAN port
on the DSL router.
Tieline codecs support automatic session
data which means you can configure the algorithm and desired bit
rate in the dialing codec and it will automatically configure the
codec in the studio once you dial in.
If the venue does not have a DHCP
network then you will need to configure a private static IP address
and enter the subnet and default gateway information into the G3
codec software. This is a simple task and you can obtain this information
from the venue network administrator.
9. Wireless Networks
You can purchase an off-the-shelf mini Wi-Fi
bridge and connect it directly to the LAN port on the rear of the
Tieline codec to interface with wireless LANs. Combine this with
Tieline’s portable in-car power or battery options and you
have a fully mobile live reporter kit.
In most cases, connecting codecs over wireless
routers is simple because it will automatically assign an IP address
to the codec and if the router is unsecured, you should be able
to successfully access the Internet immediately.
In some cases, the wireless router may be
secured using specific IP or MAC addresses. You can overcome these
obstacles by programming a static IP address into the codec and
enabling the wireless router to use that IP address or by injecting
the unique MAC address of the Tieline codec into the router. The
most difficult case we saw in our field tests required us to program
a static IP address, subnet and gateway into the codec, then program
the MAC address into the router, and finally, enter the codec’s
IP address into the router’s DMZ.
There are several caveats to be aware of
before deciding to conduct a wireless broadcast compared with a
wired IP or traditional POTS and ISDN broadcasts.
Wireless networks are far less reliable
than wired networks. Since numerous factors influence wireless transmission
you'll rarely approach the maximum networking speeds set out by
the various wireless protocols. Data transfer can vary between 30-60%
of the stated maximum depending on adapter interface, distance from
the wireless router, number of users connected to the router, number
of obstacles such as walls and types of building materials, packet
length, number of packet collisions and packet retransmissions…
the list goes on!
You can select Tieline’s ultra low
bit rate Voice G3 algorithm and deliver 7.5kHz as low as 9.6Kbps.
The smaller the stream you are sending over the network, the less
interference it will encounter on the way. However, (like the cell
phone network) be aware that wireless networks sometimes simply
drop out due to external influences beyond the codec’s control.
Most of these obstacles can be overcome
by Tieline’s unique audio algorithm and data packet management
tools which have been engineered into the internet transport protocol.
You can also manually increase the transmission and receiving buffer
in the codecs to allow for transport packet loss which significantly
improves link and audio stability.
In addition, Tieline is the only codec to
offer automatic failover to an additional POTS, ISDN or GSM link
offering unparalleled redundancy. If you’re thinking wireless….you
should also be thinking…. redundancy.
10. Why Choose Tieline’s Codec
Solution?
IP broadcasting is not just the way of the
future….it has already arrived. It’s inevitable that
Telco’s switch to VoIP and IP technologies to continue to
survive in a world where millions of customers can already talk
across the world for free using their computers. Traditional broadcasting
mediums such as ISDN, POTS and GSM will increasingly be replaced
with broadband Internet, Wi-Fi and high speed cell phone networks.
Tieline has a track record in developing
open platform codecs which has allowed us to integrate both existing
and new network technologies such as POTS, ISDN, GSM and IP into
a single codec. In a fast changing world we feel it is essential
for broadcasters to choose a broadcast codec that offers a growth
path to their evolving needs and offers investment protection against
obsolescence.
As your needs evolve, you can significantly expand our codec’s
capability by adding network modules at a very low cost compared
with buying additional dedicated codecs.
Only Tieline offers you complete redundancy
over multiple network types with the ability to have them simultaneously
dialed up and streaming audio.
If you’re interested in trialing
a G3 codec over IP, click
here to contact an authorized dealer and request a free demonstration.
Glossary of terms
IP Address
DHCP
DMZ
IP Address
An IP Address is used to identify a computer
or device on a TCP/IP network. Networks using the TCP/IP protocol
route messages based on the IP address of the destination. An IP
address is a 32-bit numeric address which is written as four seperate
numbers separated by periods. Each number can be within the range
of zero to 255. For example, 1.160.10.255 could be an IP address.
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DHCP
DHCP (Dynamic Host Configuration Protocol)
used for designating dynamic IP addresses to devices on a computer
network. A device can have a different IP address every time it
connects to the network. DHCP also supports a mix of static and
dynamic IP addresses.
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Glossary Index
DMZ
A demilitarized zone (DMZ) is a sub network
that sits between an organization’s LAN and the Internet.
It opens a single hole in the firewall and allows a computer or
other equipment to directly access the internet without exposing
all of the other computers and equipment on the LAN.
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Glossary Index
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