Support .m4b files extensions aka Audiobooks.
VLC doesn't play .m4b files (enhanced podcast/audio book format) & show the embedded pictures. They do show up as chapter images, but many .m4b files use embedded pictures as a narrated slide show, so hiding these images in a menu isn't terribly appropriate.
I was able to use ffmpeg to convert .m4b (.aac files with "chapter images") to .mp4 & play that, but that seems a bit silly, since VLC should certainly be capable of doing this on its own.
ffmpeg -i foo.m4b -acodec copy -crf 10 -r 6 -y foo.mp4
(For some reason -r 5 [or lower] doesn't seem to work for ffmpeg, but -r 6 doesn't increase the size of the file by very much, since most of the images are identical.)
produces a VLC-playable .mp4 file (which isn't even all that much bigger, since most of the images are identical).
ffmpeg -i foo.m4b -an -f image2 -q:v 1 -vsync 0 -y foo%02d.mp4
pulls out all the JPEG slides/images from the .m4b file, but forgets when each slide is supposed to be shown.