title: avconv Video flipping is taking long time, How can we reduce the process time?
body: <p>I am trying to flip video using <code>avconv</code> on Ubuntu. When it flips 1 minute video, it takes 12 to 40 seconds for processing and conversion.</p>
  
  <p>Video file size : 7mb, Duration : 1 minute</p>
  
  <pre><code>avconv -i 1_1.mp4 -c:v libx264 -c:a copy -vf "vflip" conv.mp4
  </code></pre>
  
  <p>and the result is:</p>
  
  <pre><code>avconv version 0.8.12-4:0.8.12-0ubuntu0.12.04.1, Copyright (c) 2000-2014 the Libav developers
    built on Jun 10 2014 15:32:44 with gcc 4.6.3
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1_1.mp4':
    Metadata:
      major_brand     : mp42
      minor_version   : 0
      compatible_brands: mp42mp41
      creation_time   : 2013-06-06 07:42:07
    Duration: 00:03:45.15, start: 0.000000, bitrate: 266 kb/s
      Stream #0.0(eng): Video: h264 (High), yuv420p, 640x360 [PAR 1:1 DAR 16:9], 216 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc
      Metadata:
        creation_time   : 2013-06-06 07:42:07
      Stream #0.1(eng): Audio: aac, 32000 Hz, mono, s16, 46 kb/s
      Metadata:
        creation_time   : 2013-06-06 07:42:07
  [buffer @ 0x972c240] w:640 h:360 pixfmt:yuv420p
  [libx264 @ 0x9745e20] using SAR=1/1
  [libx264 @ 0x9745e20] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2 AVX
  [libx264 @ 0x9745e20] profile Main, level 3.0
  [libx264 @ 0x9745e20] 264 - core 120 r2151 a3f4407 - H.264/MPEG-4 AVC codec - Copyleft 2003-2011 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=0 b_adapt=1 b_bias=0 direct=1 weightb=0 open_gop=1 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=1.25 aq=1:1.00
  Output #0, mp4, to 'conv.mp4':
    Metadata:
      major_brand     : mp42
      minor_version   : 0
      compatible_brands: mp42mp41
      creation_time   : 2013-06-06 07:42:07
      encoder         : Lavf53.21.1
      Stream #0.0(eng): Video: libx264, yuv420p, 640x360 [PAR 1:1 DAR 16:9], q=-1--1, 25 tbn, 25 tbc
      Metadata:
        creation_time   : 2013-06-06 07:42:07
      Stream #0.1(eng): Audio: libvo_aacenc, 32000 Hz, mono, 46 kb/s
      Metadata:
        creation_time   : 2013-06-06 07:42:07
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (h264 -&gt; libx264)
    Stream #0:1 -&gt; #0:1 (copy)
  Press ctrl-c to stop encoding
  frame= 5627 fps=153 q=-1.0 Lsize=    7880kB time=225.04 bitrate= 286.9kbits/s    
  video:6487kB audio:1271kB global headers:0kB muxing overhead 1.580010%
  [libx264 @ 0x9745e20] frame I:27    Avg QP:15.59  size: 19598
  [libx264 @ 0x9745e20] frame P:1478  Avg QP:20.11  size:  3175
  [libx264 @ 0x9745e20] frame B:4122  Avg QP:29.13  size:   344
  [libx264 @ 0x9745e20] consecutive B-frames:  1.9%  0.5%  2.1% 95.5%
  [libx264 @ 0x9745e20] mb I  I16..4: 20.1%  0.0% 79.9%
  [libx264 @ 0x9745e20] mb P  I16..4:  1.2%  0.0%  1.7%  P16..4: 23.9% 12.3%  5.6%  0.0%  0.0%    skip:55.2%
  [libx264 @ 0x9745e20] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8: 18.4%  2.3%  0.2%  direct: 0.3%  skip:78.8%  L0:41.7% L1:51.7% BI: 6.6%
  [libx264 @ 0x9745e20] coded y,uvDC,uvAC intra: 64.4% 44.0% 15.7% inter: 4.3% 4.8% 0.2%
  [libx264 @ 0x9745e20] i16 v,h,dc,p: 40% 19% 13% 28%
  [libx264 @ 0x9745e20] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 22% 17%  5%  7%  6%  6%  5%  4%
  [libx264 @ 0x9745e20] i8c dc,h,v,p: 65% 13% 19%  3%
  [libx264 @ 0x9745e20] Weighted P-Frames: Y:1.9% UV:1.2%
  [libx264 @ 0x9745e20] ref P L0: 72.8%  7.2% 13.5%  6.4%  0.0%
  [libx264 @ 0x9745e20] ref B L0: 91.2%  8.8%
  [libx264 @ 0x9745e20] kb/s:236.07
  </code></pre>
  
  <p>And time taken is 13 seconds.</p>