O filtro de desfoque FFmpeg não está funcionando

Question

Eu estou tentando desfocar o vídeo usando o FFMPEG seguindo a documentação, mas ele não está funcionando, tudo o que ele faz move os poucos quadros para frente (8 segundos de vídeo se tornam 10 segundos de vídeo e tela em branco é mostrada para 2 segundos no início)

O comando usado é

ffmpeg -i demo2.flv.mp4 -vf "boxblur=2:1" demo2.mp4

A saída completa do comando está abaixo

ffmpeg version 0.10.2 Copyright (c) 2000-2012 the FFmpeg developers
  built on Jul 16 2012 13:52:24 with gcc 4.4.3
  configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libfaac --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-x11grab --enable-libvpx --enable-libmp3lame
  libavutil      51. 35.100 / 51. 35.100
  libavcodec     53. 61.100 / 53. 61.100
  libavformat    53. 32.100 / 53. 32.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 61.100 /  2. 61.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  6.100 /  0.  6.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'demo2.flv.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf53.32.100
  Duration: 00:00:08.68, start: 0.000000, bitrate: 616 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 481 kb/s, 1000.35 fps, 1 tbr, 1k tbn, 2k tbc
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 22050 Hz, mono, s16, 36 kb/s
    Metadata:
      handler_name    : 
File 'demo2.mp4' already exists. Overwrite ? [y/N] y
w:640 h:360 pixfmt:yuv420p tb:1/1000000 sar:0/1 sws_param:
[boxblur @ 0x2c3af00] luma_radius:2 luma_power:1 chroma_radius:2 chroma_power:1 alpha_radius:2 alpha_power:1 w:640 chroma_w:320 h:360 chroma_h:180
[libx264 @ 0x2c5f4c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2
[libx264 @ 0x2c5f4c0] profile High, level 2.2
[libx264 @ 0x2c5f4c0] 264 - core 125 r2200 999b753 - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - 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=1 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 'demo2.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf53.32.100
    Stream #0:0(und): Video: h264 (![0][0][0] / 0x0021), yuv420p, 640x360, q=-1--1, 1 tbn, 1 tbc
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (@[0][0][0] / 0x0040), 22050 Hz, mono, s16, 128 kb/s
    Metadata:
      handler_name    : 
Stream mapping:
  Stream #0:0 -> #0:0 (h264 -> libx264)
  Stream #0:1 -> #0:1 (aac -> libfaac)
Press [q] to stop, [?] for help
Segmentation fault