Encoder libopus [libopus Opus]:
    General capabilities: delay small 
    Threading capabilities: none
    Supported sample rates: 48000 24000 16000 12000 8000
    Supported sample formats: s16 flt
libopus AVOptions:
  -application       <int>        E...A.... Intended application type (from 2048 to 2051) (default audio)
     voip            2048         E...A.... Favor improved speech intelligibility
     audio           2049         E...A.... Favor faithfulness to the input
     lowdelay        2051         E...A.... Restrict to only the lowest delay modes
  -frame_duration    <float>      E...A.... Duration of a frame in milliseconds (from 2.5 to 120) (default 20)
  -packet_loss       <int>        E...A.... Expected packet loss percentage (from 0 to 100) (default 0)
  -vbr               <int>        E...A.... Variable bit rate mode (from 0 to 2) (default on)
     off             0            E...A.... Use constant bit rate
     on              1            E...A.... Use variable bit rate
     constrained     2            E...A.... Use constrained VBR
  -mapping_family    <int>        E...A.... Channel Mapping Family (from -1 to 255) (default -1)
  -apply_phase_inv   <boolean>    E...A.... Apply intensity stereo phase inversion (default true)


