Bounds checking quietly returns zero when out of bounds

the bbWrap funcion in blueberry-transcoder.c simply returns zero if the specified index is out of bounds of the buffer.

This causes an out-of-bounds write to paste over index zero of the buffer, which is probably not a great thing.

probably should think of something else to do that is more detectible.

Start in blueberry-transcoder.c at the bbWrap function and trace its callers to understand how an out-of-bounds result becomes a write to index zero. Determine the intended detectable failure behavior with the project maintainers, then verify that invalid indices cannot overwrite the buffer and that valid indexing remains unchanged.

Written by the indexing model from the issue text.