Recording Format
Click Recording Format to choose between recording raw sonar data (to a “.mmb” file) or recording beamformed sonar data (to a “.imb” file).
.mmb
.mmb is the default recommended recording format.
This is raw element data, not beamformed, in a 16-bit fixed-point complex format. This format allows great flexibility in how the data is processed and allows you to do your own beamforming or profile-point extraction. The data body size is determined by the number of elements and the number of samples.
If you want to keep your recordings in .mmb format but process your data in .imb format, you can convert .mmb files to .imb files using a batch conversion utility.
.imb
This format consists of beamformed data.
You can choose between a 32-bit floating point complex or 8-bit integer magnitude format. Select the 8-bit format only if you are interested in imaging pixel data and want a reduced data file size. The 8-bit format takes up a quarter of the 32-bit format's size.
Data body size is determined by the number of beams and samples. Different modes may form a different number of beams. Therefore, data body size may change depending upon the mode.
.imb files are easier to work with when using the M3 Sonar MATLAB toolbox and can be used with third-party software, such as Echoview.
Note
If files are recorded in .imb format, they cannot be converted to .mmb.