Studio Technologies 5154 - Manual (Page 23)

Model 5154 User Guide Issue 3, September 2013
Studio Technologies, Inc. Page 23
Model 5154
Video Generator/Audio De-Embedder Module
Note that two of the eight choices provide
DA (distribution amplifier) functions, de-
embedding only one group from the SDI
input and routing those two audio pairs to
all four of the digital audio outputs. Refer
to the [OPTIONS] section of Figure 7 to
review a list of de-embedding configuration
choices.
The de-embedding process does not alter
an input SDI signal. It will pass through,
unaltered, to the coaxial (BNC) and, if
present, optical outputs.
There are eight signal present status LEDs
associated with the eight audio output
channels. (Two audio channels are associ-
ated with each of the four AES3-compat-
ible digital audio outputs.) A signal present
LED will light when its associated audio
channel has a signal level that equals or
exceeds –40 dBFS. This level is 20 dB
below the nominal audio level of –20 dBFS
for SMPTE applications. For EBU applica-
tions it will light 22 dB below the nominal
–18 dBFS level.
As expected, audio can only be de-
embedded when a valid source has been
connected to the coaxial (BNC) or optical
SDI input. If no signal is present on the
SDI input, or the connected SDI source
doesn’t have the required audio group
data present, the four digital audio outputs
will remain active but no audio data will
be present. Actually, audio data will be
present in the AES3 data “stream” but it
will consist of all “0”s. A device connected
to the module’s digital audio outputs will
recognize them as being valid AES3 sig-
nals but with audio levels at their technical
minimum.
Technical Notes
Bitmap Image File
Requirements
The Model 5154 allows two bitmap (.bmp)
images to be stored and output when an
SDI input signal is not present. One image
has a pixel size of 1280 x 720 while the
other has a pixel size of 1920 x 1080. To
be stored with the Model 5154 the files
must be FAT32-compatible and have
names of img720.bmp and img1080.bmp,
respectively.
The reason two files are required is simple:
the Model 5154 does not have the ability to
digitally “scale” a 1920 x 1080 image down
to 1280 x 720. But it does have the ability to
store two unique files. Most users will create
a single image using a personal-computer
graphics program and then save it in the two
required formats. So when the Model 5154
generates either of the two images (“720” or
“1080”), a user will see what appears to be
an identical image. But there is no reason
why the two images (“720” and “1080”) have
to be based on the same original graphics.
Studio Technologies chose to create two dif-
ferent “720” and “1080” bitmap files that are
pre-loaded in the Model 5154 at the time
of manufacture. They feature two unique
background images with text highlighting
the main requirements for updating them.
While the two bitmap files (img720.bmp
and img1080.bmp) are “standard” in the
sense that they are FAT32-compatible and
have the extension .bmp, they must adhere
to one important requirement that not all
personal-computer graphics programs sup-
port. Their DIB (bitmap information header)
must be a BITMAPINFOHEADER type.
The Microsoft Paint and Adobe Photoshop