int write_frame(VFrame *frame, VFrame *data, FrameWriterUnit *unit);
int can_copy_from(Asset *asset, int64_t position);
int read_frame_header(char *path);
int write_frame(VFrame *frame, VFrame *data, FrameWriterUnit *unit);
int can_copy_from(Asset *asset, int64_t position);
int read_frame_header(char *path);