Ozeki NG SMS Gateway

Operator logo converter

We have found this article at codeproject, and since it is very useful, for those who want to work with the OTA bitmap format we have decided to post a copy of it:


I searched the internet for a program to convert the image files to the OTA file format, but there was none!!! So, I began researching for OTA file format details... finally, I wrote a program with C# to do this...

The source code and binary files are ready for download...

The main logic of this program is an algorithm for converting images. Mobile picture messages (OTA or OTB files) have a standard size: 72x28. First of all we must create a file (*.ota) and then write 4 standard bytes into it.

byte0 -> 0000 0000 (0)
byte1 -> 0100 1000 (72)
byte2 -> 0001 1100 (28)
byte3 -> 0000 0001 (1)

Now read image, pixel by pixel, from left to right and top to bottom, every 8 pixel makes a byte for writing to the file:

black pixels = 0
Other pixels = 1

An image with size 72x28:

has 72*28 = 2016 (bits)
every 8 bits = 1 byte => 2016 / 8 = 252
and 252(bytes) + 4(standard bytes) = 256 bytes

Finally, the file size is 256 bytes.

Download and read my source code to see this program working...

Author: Alireza Naghizadeh, Iran
Original articale is available at: http://www.codeproject.com/KB/graphics/ota_converter.aspx?msg=2384564