Muxer spdif [IEC 61937 (used on S/PDIF - IEC958)]:
    Common extensions: spdif.
    Default audio codec: ac3.
spdif AVOptions:
-spdif_flags       <flags>      E..... IEC 61937 encapsulation flags
   be                           E..... output in big-endian format (for use as s16be)
-dtshd_rate        <int>        E..... mux complete DTS frames in HD mode at the specified IEC958 rate (in Hz, default 0=disabled) (from 0 to 768000)
-dtshd_fallback_time <int>        E..... min secs to strip HD for after an overflow (-1: till the end, default 60) (from -1 to INT_MAX)

