+ The chunk_num argument must be between -num_chunks and
+ num_chunks - 1 inclusively where num_chunks is the total number
+ of chunks which is printed when using the --info option. If
+ chunk_num is negative, the given number of chunks are counted
+ backwards from the end of the file. For example --begin_chunk
+ -100 instructs para_afh to start output at chunk num_chunks
+ - 100. This is mainly useful for cutting off the end of an
+ audio file.