title: How do I debug why avconv is stalling?
body: <p>I'm converting .mov files to .mpg files using avconv. The command being run by my php application is as follows:</p>
  <blockquote>
  <p>avconv -y -i '$finalvideo' -target ntsc-dvd -aspect 4:3 '$mpgvideo' &gt; $logs</p>
  </blockquote>
  <p>I'm able to convert small .mov files to .mpg without any problems. However, I'm unable to convert videos that are over ten or fifteen minutes long. The log file is completely empty. When I run the command directly the frame stops somewhere around 34000 no matter which video I pick.</p>
  <p>The cpu shows 97% usage on this process, however, nothing is happening.</p>
  <p>OS Ubuntu 10~</p>
  <h3>How can I gather more information about this stalled process?</h3>
  <p>Here's the frozen output</p>
  <pre><code>avconv version 0.7, Copyright (c) 2000-2011 the Libav developers
    built on Nov  3 2011 13:39:09 with gcc 4.3.3
  
  Seems stream 0 codec frame rate differs from container frame rate: 180000.00 (180000/1) -&gt; 23.98 (24000/1001)
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/sites/default/files/compiled_videos/573-stream.mov':
    Metadata:
      major_brand     : qt  
      minor_version   : 512
      compatible_brands: qt  
      creation_time   : 1970-01-01 00:00:00
      encoder         : Lavf53.0.3
    Duration: 00:18:53.49, start: 0.000000, bitrate: 1430 kb/s
      Stream #0.0(eng): Video: h264 (Main), yuv420p, 854x480, 1387 kb/s, 25.60 fps, 23.98 tbr, 90k tbn, 180k tbc
      Metadata:
        creation_time   : 1970-01-01 00:00:00
      Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 126 kb/s
      Metadata:
        creation_time   : 1970-01-01 00:00:00
  [buffer @ 0x9d88820] w:854 h:480 pixfmt:yuv420p
  [scale @ 0x9d88b60] w:854 h:480 fmt:yuv420p -&gt; w:720 h:480 fmt:yuv420p flags:0x4
  Incompatible sample format 's16' for codec 'ac3', auto-selecting format 'flt'
  Output #0, dvd, to '/var/www/sites/default/files/compiled_videos/573.mpg':
    Metadata:
      major_brand     : qt  
      minor_version   : 512
      compatible_brands: qt  
      creation_time   : 1970-01-01 00:00:00
      encoder         : Lavf53.10.0
      Stream #0.0(eng): Video: mpeg2video, yuv420p, 720x480 [PAR 8:9 DAR 4:3], q=2-31, 6000 kb/s, 90k tbn, 29.97 tbc
      Metadata:
        creation_time   : 1970-01-01 00:00:00
      Stream #0.1(eng): Audio: ac3, 48000 Hz, stereo, flt, 448 kb/s
      Metadata:
        creation_time   : 1970-01-01 00:00:00
  Stream mapping:
    Stream #0.0 -&gt; #0.0 (h264 -&gt; mpeg2video)
    Stream #0.1 -&gt; #0.1 (aac -&gt; ac3)
  Press ctrl-c to stop encoding
  [mpeg2video @ 0x9d8bf20] rc buffer underflow
  Input stream #0.1 frame changed from rate:48000 fmt:s16 ch:2 to rate:48000 fmt:flt ch:2
  frame=33910 fps= 91 q=2.0 size=  151922kB time=336.58 bitrate=3697.7kbits/s dup=5475 drop=530    
  </code></pre>
  <p>Oh interesting. I used -loglevel debug -debug. I was seeing this information</p>
  <pre><code>stream #0:
    keyframe=0
    duration=0.000
    dts=1133.449  pts=1133.533
    size=103
  *** 1 dup!
  stream #0:
    keyframe=0
    duration=0.000
    dts=1133.449  pts=1133.449
    size=104
  </code></pre>
  <p>Until I finally received this message</p>
  <pre><code>*** drop!
  </code></pre>
  <p>I have posted my bug with libav
  <a href="http://bugzilla.libav.org/show_bug.cgi?id=67" rel="nofollow noreferrer">http://bugzilla.libav.org/show_bug.cgi?id=67</a></p>
  <p>thanks for your help.</p>