From BlinkenArea Wiki
A BlinkströmAdvanced BIN file contains data for each frame in sequence: the display duration (2 bytes, little endian, multiplied by 20 ms) and the brightness value for each pixel (one byte per pixel, binary values between 0 [off] and 7 [maximum brightness]). The order is from top to bottom, then from left to right (i.e. columns before rows).
This format is also supported by BlinkenPlus. For color projects, the number of columns has to be multiplied by the number of channels, e.g. 54 columns total for a project with 18x8 pixels and 3 colors (RGB). The file then contains one column for each color, which means that three consecutive columns in the file are needed for one RGB LED column. The columns start with the one for red.