If the EBML head not found it display:: EBML head not found! Are you sure it's a matroska/webm file?
And deletes the video !
This is very crappy
What version are you using ? It used to be a bug but it is not present in the latest version.
Also what system are you on ?
Im using version v.0.7.3.
Debian Lenny 5.0
I have posted the Bug Above
I can't reproduce it on Ubuntu 32 bits and Ubuntu 64 bits with 0.7.3 sources. What is the command line you are using ? The only case I can think of is if the source and destination files are the same (not good in any case).