Segmentation fault with header removal compression of size zero
I am currently checking FFmpeg's handling of content compressions and in the course of doing so I stumbled upon a segfault in mkvmerge: If one has a track with header removal compression and if the ContentCompSettings of the relevant ContentCompression has a length of zero, mkvmerge segfaults. It also does this when I void all the clusters, so that it must happen during parsing the header. Additionally, mkvinfo skips the ContentCompSettings completely (maybe it does this for all EBML binary elements of size 0?).
I uploaded Pro.mkv to your server.
PS: Btw: I tried creating bz2 compressed tracks with old versions of mkvmerge (6.1 and older) and failed: Not even the mkvmerge that created these files can read them. Which is a bit odd, because I don't see an error in the compression code (apart from the fact that a buffer twice as big as the input is not necessarily enough, but in case no error happens the output should be fine; but it isn't). Very weird.
PPS: This issue has been found in version 40.0, but it probably affects 41.0 as well.