documentation from Qt for LBO layer memory on the Traveo states

The documentation from Qt for LBO layer memory on the Traveo states
Specifically, while IBO mode requires width*height*bpp*2 bytes to store a double buffered set of framebuffers, the LBO line buffer only requires width*lines*bpp bytes, where lines is the height of the line buffer. By default lines is set to 64 on TRAVEO T2G CYT3DL and 128 on TRAVEO T2G CYT4DN and TRAVEO T2G CYT4EN, but it can be configured using the approach described in the Advanced layer configuration section. Some additional smaller buffers are also needed for rendering instructions and other rendering-related tasks.

Documentation states : LBO memory needed is width*lines*bpp