Muxer spx [Ogg Speex]:
    Common extensions: spx.
    Mime type: audio/ogg.
    Default audio codec: speex.
Ogg Speex muxer AVOptions:
  -serial_offset     <int>        E........ serial number offset (from 0 to INT_MAX) (default 0)
  -oggpagesize       <int>        E........ Set preferred Ogg page size. (from 0 to 65025) (default 0)
  -pagesize          <int>        E........ preferred page size in bytes (deprecated) (from 0 to 65025) (default 0)
  -page_duration     <int64>      E........ preferred page duration, in microseconds (from 0 to I64_MAX) (default 1000000)


