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Saturday, December 30, 2006

Open source debugging

While trying to re-encode some podcasts (to have smaller file size), I learned the following lessons:

  • MediaCoder looked very, very professional and I wanted to try it out for a long time. However, it freaked out over my MP3 file and crashed the included MPlayer. No problem I thought, I downloaded the latest Windows build of Mplayer from the main website and replaced the files. Now the encoding errors out on the files with no details about what went wrong. I tried to fiddle with the settings but no success. Maybe it only encodes / transcodes video files?
  • I suspected that the problem was that then included Mplayer version was compiled without runtime CPU detection, but I just checked and the machine I'm on supports all the required instruction sets (MMX and SSE)
  • The user interface is cryptic from time to time with to apparent information source about what some controls mean. For example I assume that the Algorithm Quality slider on the LAME page is equivalent to the -q switch for the command line.
  • My preferred audio player does not have output plugins which encode audio on the fly
  • Winamp doesn't have an output plugin to encode to OGG directly (although it has one for MP3)
  • Re-encoding low quality files produces really bad results, so I gave up on it

And finally:

  • The Sourceforge site has a bug, which can lead you to incorrect links when downloading files whose names contain special characters (like gcc-g++-3.4.5-20060117-1.tar.gz for example). The bug occurs if for whatever reason you don't download the file from the first mirror it offers you and you select an other one. During the redirection it fails to correctly URLEncode the file name, but it tries to decode at the other end, resulting in the link pointing to gcc-g -3.4.5-20060117-1.tar.gz - because + stands for space in URLEncoding. To resolve this, you can either use the back button of your browser to go back to the file list page and click again on the file (your mirror preferences are remembered in a cookie) or look at the direct link and replace the erroneously encoded characters with the right ones. You can use The URLEncode and URLDecode Page to help you with this. In my case this would be gcc-g%2B%2B-3.4.5-20060117-1.tar.gz . They have been notified.


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