fbhalve converts unicode art files that use U+2588 FULL BLOCK characters to
an image that is halve the size of the original, by using smaller unicode
block characters such as U+2580 UPPER HALF BLOCK.
Keep in mind that asciinema does not show FULL BLOCK characters that well, normally the characters "connect" in a terminal.
You need any C compiler to build fbhalve. Builds can be done using the make command:
Bugs & todo here: ~pingiun/fbhalve