Studio Technologies 5150 V.1 - Manual (Page 23)

Model 5150 User Guide Issue 5, March 2014
Studio Technologies, Inc. Page 23
Model 5150
Video Generator Module
Technical Notes
Bitmap Image File
Requirements
The Model 5150 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 5150 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 5150 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 5150 generates either of the two im-
ages (“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 orig-
inal graphics. Studio Technologies chose to
create two different “720” and “1080” bitmap
files that are pre-loaded in the Model 5150
at the time of manufacture. They feature two
unique background images with text high-
lighting 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 5150.
The possibility that various .bmp files will
have different header types doesn’t seem to
be an issue for displaying them successfully
with most personal-computer programs.
This is most likely due to the PC’s large
code space allowing essentially all the pos-
sible header types to be supported. But the
Model 5150, due to its target application,
has limitations in the file support area. (For
additional background information, please
refer to the Wikipedia online entry that dis-
cusses the structure of .bmp files.)
A compatible 1280 x 720 (“720”) .bmp
file created using Microsoft Paint or Adobe
Photoshop will have a size of approximately
2.63 MB; a 1920 x 1080 (“1080”) .bmp file
will have a size of approximately 5.63 MB.
The actual size of the files when created in
Microsoft Paint should be 2,764,854 bytes
and 6,220,854 bytes, respectively. When
created in Adobe Photoshop, the file sizes
should be 2,764,856 bytes and 6,220,856
bytes, respectively. (Why are they each
two bytes in size different? Who knows!
But both use the appropriate BITMAPINFO-
HEADER DIB type.)
Bitmap Image Update
Procedure
It’s expected that the Model 5150’s bitmap
(.bmp) files associated with the custom
“720” and “1080” images will always be
updated to best serve specific applications.
This will typically take place soon after a