When rendering a video containing at least two consecutive titles using an image and a key-framed fade-in, fade-out, melt crashes in libwscale passing a NULL pointer.
This specific "NULL pointer not checked" stuff has already been reported and fixed in ffmpeg but the original cause still remains.
It appears that the root of this issue takes place in the function "mlt_geometry_parse_item" of file "src/framework/mlt_geometry.c". This is the code in charge of parsing a geometry instruction. It uses the function "strtod" which is **local dependant**. In this function, it is assumed that the decimal separator is a "." whereas it is a "," in french. The "," is also a field separator and it causes the parser to read weird values :D
Adding "setlocale(LC_NUMERIC, "C");" at the beginning of the function appears to be a quite good workaround at the moment. This is the one i am currently using.
Anyway, i still have a silly questions:
=> why does this bug appears only on the SECOND title using an image ???
Note that fixing the sigsegv in the libwscale code helps the video the play, without the title using images but all the other following titles are fine !
=> Is it possible that the local is changed at some point in the program ?