* function also returns NULL. Otherwise a copy of the tag value is returned
* and the caller should free this memory when it is no longer needed.
*/
-char *mp4_get_tag_value(const struct mp4 *f, const char *item)
+__malloc char *mp4_get_tag_value(const struct mp4 *f, const char *item)
{
for (unsigned n = 0; n < f->meta.count; n++)
if (!strcasecmp(f->meta.tags[n].item, item))