Muxer 3gp [3GP (3GPP file format)]:
    Common extensions: 3gp.
    Default video codec: h263.
    Default audio codec: amr_nb.
tgp muxer AVOptions:
  -movflags          <flags>      E..... MOV muxer flags
     rtphint                      E..... Add RTP hint tracks
     empty_moov                   E..... Make the initial moov atom empty (not supported by QuickTime)
     frag_keyframe                E..... Fragment at video keyframes
     separate_moof                E..... Write separate moof/mdat atoms for each track
     frag_custom                  E..... Flush fragments on caller requests
     isml                         E..... Create a live smooth streaming feed (for pushing to a publishing point)
     faststart                    E..... Run a second pass to put the moov at the beginning of the file
  -moov_size         <int>        E..... maximum moov size so it can be placed at the begin (from 0 to INT_MAX)
  -rtpflags          <flags>      E..... RTP muxer flags
     latm                         E..... Use MP4A-LATM packetization instead of MPEG4-GENERIC for AAC
     rfc2190                      E..... Use RFC 2190 packetization instead of RFC 4629 for H.263
     skip_rtcp                    E..... Don't send RTCP sender reports
     h264_mode0                   E..... Use mode 0 for H264 in RTP
  -skip_iods         <int>        E..... Skip writing iods atom. (from 0 to 1)
  -iods_audio_profile <int>        E..... iods audio profile atom. (from -1 to 255)
  -iods_video_profile <int>        E..... iods video profile atom. (from -1 to 255)
  -frag_duration     <int>        E..... Maximum fragment duration (from 0 to INT_MAX)
  -min_frag_duration <int>        E..... Minimum fragment duration (from 0 to INT_MAX)
  -frag_size         <int>        E..... Maximum fragment size (from 0 to INT_MAX)
  -ism_lookahead     <int>        E..... Number of lookahead entries for ISM files (from 0 to INT_MAX)
  -use_editlist      <int>        E..... use edit list (from -1 to 1)
  -video_track_timescale <int>        E..... set timescale of all video tracks (from 0 to INT_MAX)

