No pixel format specified, yuv422p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[libx264 @ 0x80d88da00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0x80d88da00] profile High 4:2:2, level 3.0, 4:2:2 8-bit
[libx264 @ 0x80d88da00] 264 - core 144 r2533 c8a773e - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - 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=12 lookahead_threads=2 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, matroska, to 'output.mkv':
  Metadata:
    encoder         : Lavf56.36.100
    Stream #0:0: Video: h264 (libx264) (H264 / 0x34363248), yuv422p, 640x480, q=-1--1, 30 fps, 1k tbn, 30 tbc
    Metadata:
      encoder         : Lavc56.41.100 libx264
    Stream #0:1: Audio: vorbis (libvorbis) (oV[0][0] / 0x566F), 48000 Hz, stereo, fltp
    Metadata:
      encoder         : Lavc56.41.100 libvorbis
Stream mapping:
  Stream #1:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  Stream #0:0 -> #0:1 (pcm_s16le (native) -> vorbis (libvorbis))
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[video4linux2,v4l2 @ 0x80d87aa00] Thread message queue blocking; consider raising the thread_queue_size option (current value: 8)
Past duration 0.927620 too large
[oss @ 0x80d87a400] Thread message queue blocking; consider raising the thread_queue_size option (current value: 8)
frame=   94 fps= 16 q=27.0 size=     268kB time=00:00:05.63 bitrate= 389.2kbits/s dup=0 drop=28