ffmpeg -y -i
"input.flv" -vf "[in] split [T1], fifo, [T2] overlay=0:H/2 [out]; [T1] fifo, cro
p=iw:ih/2:0:ih/2, vflip [T2]" output.mp4
ffmpeg version N-41195-g8a0efa9 Copyright (c) 2000-2012 the FFmpeg developers
  built on May 31 2012 20:10:06 with gcc 4.6.3
  configuration: --disable-static --enable-shared --enable-gpl --enable-version3
 --disable-w32threads --enable-runtime-cpudetect --enable-avisynth --enable-bzli
b --enable-frei0r --enable-libass --enable-libcelt --enable-libopencore-amrnb --
enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --enable-libmp3lam
e --enable-libnut --enable-libopenjpeg --enable-librtmp --enable-libschroedinger
 --enable-libspeex --enable-libtheora --enable-libutvideo --enable-libvo-aacenc
--enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --en
able-libxavs --enable-libxvid --enable-zlib
  libavutil      51. 55.100 / 51. 55.100
  libavcodec     54. 23.100 / 54. 23.100
  libavformat    54.  6.101 / 54.  6.101
  libavdevice    54.  0.100 / 54.  0.100
  libavfilter     2. 77.100 /  2. 77.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, flv, from 'input.flv':
  Metadata:
    starttime       : 0
    totalduration   : 474
    totaldatarate   : 1005
    bytelength      : 59533158
    canseekontime   : true
    sourcedata      : B4A7D0021HH1338775178100633
    purl            :
    pmsg            :
  Duration: 00:07:53.76, start: 0.000000, bitrate: 1005 kb/s
    Stream #0:0: Video: h264 (Main), yuv420p, 854x480, 890 kb/s, 25 tbr, 1k tbn,
 50 tbc
    Stream #0:1: Audio: aac, 44100 Hz, stereo, s16, 130 kb/s
[fifo @ 0000000003027b60]
[fifo @ 0000000003027ce0]
[buffer @ 0000000003027ae0] w:854 h:480 pixfmt:yuv420p tb:1/1000 sar:0/1 sws_par
am:flags=2
[buffersink @ 00000000006f29e0] No opaque field provided
[overlay @ 0000000003027dc0] auto-inserting filter 'auto-inserted scaler 0' betw
een the filter 'Parsed_fifo_1' and the filter 'Parsed_overlay_2'
[crop @ 0000000003027900] w:854 h:480 sar:0/1 -> w:854 h:240 sar:0/1
[scale @ 0000000003027f20] w:854 h:480 fmt:yuv420p sar:0/1 -> w:854 h:480 fmt:yu
va420p sar:0/1 flags:0x4
[overlay @ 0000000003027dc0] main w:854 h:240 fmt:yuv420p overlay x:0 y:120 w:85
4 h:480 fmt:yuva420p
[overlay @ 0000000003027dc0] Overlay area (0,120)<->(854,600) not within the mai
n area (0,0)<->(854,240) or zero-sized
Error opening filters!