eng TELE-audiovision 1411

that meet precise requirements without
technicians having to familiarise themselves
with new control interfaces for
each device.
All used encoders are compatible with
H.264 (MPEG-4 Part 10 AVC according
to ISO / IEC 14496-10) and can create
streams with either CBR (constant bit
rate) or VBR (variable bit rate), depending
on the configuration of the device.
MPEG-4 Part 10 can easily be called the
most popular format for video compression
today and has become the
established standard for recording and
distributing video content.
For our in-depth test the CW-4412
variant was shipped to the TELE-audiovision
Test Center. The device is packaged
inside a sturdy cardboard, which
makes sure it arrives at its destination
in mint condition. Apart from the encoder
itself and the power cable there
were only two sheets of paper inside
the box: One contained the operating
manual in English, the other one featured
instructions for the web interface.
Both texts are rather concise and
only provide essential steps for operation:
The CW-4412 can either be controlled
via Windows software or directly
through its web interface from any web
browser. The default IP addresses for
accessing the encoder are also given in
the instructions.
With its white rack-sized case the
CW-4412 looks just as unpretentious as
the instruction manual: The only physical
control element is an On/Off switch
on the back panel of the encoder. What
the back panel does feature, however,
is an abundance of connection options.
Owing to the fact that the CW-4412 is
capable of simultaneously compressing
two independent input signals into the
MPEG-4 format we have two connection
interfaces each for SDI, component
video (YUV), composite video and
HDMI. As far as outputs are concerned
this encoder sports a total of four ASI
outputs, which means there are two
ASI sockets for each of the two encoders.
Two USB ports – again, one for
each encoder – are available for firmware
updates.
Turning to the front panel, we find 10
LEDs which indicate the encoders’ current
operating mode. Divided into three
sections, 4 LEDs on the left refer to
encoder 1 (Input 1, BUSY, HD and ER-
ROR), 4 LEDs on the right do the same
for encoder 2, while the middle section
indicates the following general states:
LINK, ACT, PWR and FIBER.
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With the clear labelling of those LEDs,
their purpose is more or less self-explanatory:
INPUT 1 and INPUT 2: These two
LEDs indicate whether or not a signal is
fed into the encoders.
BUSY: A slowly flashing LED indicates
that new firmware is being loaded.
If the LED flashes in short intervals,
this indicates that process parameters
are loaded by the computer. In both
cases the MPEG-4 compression routine
is temporarily stopped. In general,
however, such interruptions do not last
longer than 1 or 2 seconds.
HD: Lights up whenever an HD signal
is available from the encoder input.
ERROR: In case an error occurs during
the encoding process this LED will
light up. This can happen if the process
SW-4412
1. This application allows to configure the
input signal on the CW-4412 encoder. You
can convert high resolution signals to
lower resolution signals. Also, it is possible
to select if a constant bit rate (CBR) or a
variable bit rate (VBR) should be used. The
latter can be used to decrease the summed
bit rate of a transport stream containing
many channels: in average different channels
rarely have high bit rate requirements
in the same moment in time, which helps
keeping the overall transport stream bit
rate low. To use the VBR option, different
interdependent parameters have to be
specified. Fortunately, the CW-4412 will let
you know instantly if they make sense and
suggest how to calculate correct values –
this will help you save the time of digging
out reference manuals. Another important
set of configurable parameters that include
the Service Provider and Service Name and
the allocated Video, Audio, PMT, PCR, TS
and TXT PID’s.
2. Clicking on the MPEG Encoder -2 tab will
simply open the exact same set of parameters
for the second encoder of the CW-4412.
In fact, the CW-4412 acts as two independent
MPEG-4 encoders, which just happen
to share the same case, power supply and
operational frontend.
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18 TELE-audiovision International — The World‘s Leading Digital TV Industry Publication — 11-12/2014 — www.TELE-audiovision.com