root@raspberrypi:/cppcode# ffmpeg -i video0.mp4 -vcodec libx264 -f mp4 video0o.mp4
ffmpeg version N-86815-gf04ef26 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 4.9.2 (Raspbian 4.9.2-10)
  configuration: --enable-gpl --enable-nonfree --enable-pthreads --enable-libx264 --enable-libfdk-aac --enable-libmp3lame
  libavutil      55. 68.100 / 55. 68.100
  libavcodec     57.102.100 / 57.102.100
  libavformat    57. 76.100 / 57. 76.100
  libavdevice    57.  7.100 / 57.  7.100
  libavfilter     6. 95.100 /  6. 95.100
  libswscale      4.  7.101 /  4.  7.101
  libswresample   2.  8.100 /  2.  8.100
  libpostproc    54.  6.100 / 54.  6.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video0.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.76.100
  Duration: 00:00:00.97, start: 0.000000, bitrate: 29 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 320x240 [SAR 1:1 DAR 4:3], 19 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
    Metadata:
      handler_name    : VideoHandler
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[libx264 @ 0x3391750] using SAR=1/1
[libx264 @ 0x3391750] using cpu capabilities: ARMv6 NEON
[libx264 @ 0x3391750] profile High, level 1.3
[libx264 @ 0x3391750] 264 - core 152 r2851 ba24899 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'video0o.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.76.100
    Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 320x240 [SAR 1:1 DAR 4:3], q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc57.102.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame=   29 fps=0.0 q=-1.0 Lsize=       4kB time=00:00:00.86 bitrate=  33.6kbits/s speed=3.35x
video:2kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 49.240871%
[libx264 @ 0x3391750] frame I:1     Avg QP: 5.82  size:    68
[libx264 @ 0x3391750] frame P:7     Avg QP:13.28  size:   120
[libx264 @ 0x3391750] frame B:21    Avg QP:16.85  size:    40
[libx264 @ 0x3391750] consecutive B-frames:  3.4%  0.0%  0.0% 96.6%
[libx264 @ 0x3391750] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x3391750] mb P  I16..4:  3.7%  9.0%  0.0%  P16..4:  7.7%  0.3%  0.0%  0.0%  0.0%    skip:79.3%
[libx264 @ 0x3391750] mb B  I16..4:  0.1%  0.0%  0.0%  B16..8:  3.8%  0.1%  0.0%  direct: 1.5%  skip:94.5%  L0:20.9% L1:79.1% BI: 0.0%
[libx264 @ 0x3391750] 8x8 transform intra:33.0% inter:100.0%
[libx264 @ 0x3391750] coded y,uvDC,uvAC intra: 0.7% 3.1% 0.0% inter: 0.1% 1.3% 0.0%
[libx264 @ 0x3391750] i16 v,h,dc,p: 85%  6%  8%  1%
[libx264 @ 0x3391750] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 16% 28% 56%  0%  0%  0%  0%  0%  0%
[libx264 @ 0x3391750] i8c dc,h,v,p: 83% 12%  5%  0%
[libx264 @ 0x3391750] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x3391750] ref P L0: 89.7%  0.4%  4.8%  5.1%
[libx264 @ 0x3391750] ref B L0: 85.4% 13.6%  1.0%
[libx264 @ 0x3391750] ref B L1: 99.0%  1.0%
[libx264 @ 0x3391750] kb/s:14.47