- <para>When used with --ogg, specifies the serial
- number to use for the FLAC stream. When encoding and
- no serial number is given, flac uses '0'. When
- decoding and no number is given, flac uses the serial
- number of the first page.</para>
+ <para>When used with --ogg, specifies the serial number to
+ use for the first Ogg FLAC stream, which is then
+ incremented for each additional stream. When encoding and
+ no serial number is given, flac uses a random number for
+ the first stream, then increments it for each additional
+ stream. When decoding and no number is given, flac uses
+ the serial number of the first page.</para>