how big is the data? there's a 16MB limit for metadata blocks. see src/share/grabbag/picture.c:grabbag__picture_parse_specification() for examples of function usage. --- On Mon, 3/8/10, Anthony Liu <quadamage at gmail.com> wrote: ... The above code will add a NULL cover art into the flac file, it works. However, after I add the following code between the call of?FLAC__metadata_iterator_next ?and ?FLAC__metadata_object_picture_is_legal, I got a "fail to write: status 0" message. ... I did some tests and it seemed that the error was caused by the?FLAC__metadata_object_picture_set_data function, the members of picture object like?width,?height,?depth,?colors?were not initialized, are they mandatory or optional? What's wrong with the code??Please help!