Studio Technologies 5152 V.3 - Manual (Page 20)

Issue 2, June 2013 Model 5152 User Guide
Page 20 Studio Technologies, Inc.
Model 5152
Video Generator/Audio Embedder Module
A subtle but potentially important topic
must be covered. With the Model 5152’s
embedding flexibility it’s possible that equip-
ment connected to its SDI output could
exhibit less-than-desirable performance.
Embedded audio data will only be present
on the Model 5152’s SDI output according
to the configuration settings. There is no
requirement that a specific group, such as
group 1, be active. In the case where no
valid SDI source is connected to the Model
5152’s SDI input, the SDI output signal
will consist of the custom “720” or “1080”
image along with the embedded audio. As
such, ancillary data created by the embed-
ding process will only be present for the
specific configured audio group or groups.
For example, if the Model 5152 has been
configured for digital audio inputs 1 and 2
to be embedded into SDI group 3, then
there will be no ancillary data packets
present in the SDI output for groups 1, 2,
and 4. Only if a connected SDI signal has
embedded audio on those groups (1, 2, and
4) will they be present in the Model 5152’s
SDI output. This can be significant as it’s
been discovered that some equipment that
receives SDI signals expects that embed-
ded audio will be present, at a minimum,
on group 1. So embedding audio, as an
example, that is only present on group 3
could cause an issue.
Technical Notes
Bitmap Image File
Requirements
The Model 5152 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 5152 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 5152 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 5152
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 5152 at the time of
manufacture. They feature two unique back-
ground 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 appli-
cations will create .bmp files that meet this
requirement. But some other programs may
produce non-compatible files. For example,
the open-source GIMP graphics program
is very good but appears to save .bmp files
only as a BITMAPV4HEADER type. These
are not compatible with the Model 5152.
The possibility that various .bmp files will
have different header types doesn’t seem to
be an issue for displaying them successfully