The ElementaryDesign HTTP Streaming HowTo

Preparing Files for HTTP Streaming

An Overview of the Entire Process:

  1. Start with a high quality audio file. Typically, this means a CDDA/Red Book file, a format invented by Sony and Philips in 1982. Never heard of it? CDDA refers to CD Digital Audio, the file format still used to store audio data on compact discs. Do not start with a file that has been converted from a compressed format, like mp3 or Ogg Vorbis, to a file that will play in a standard CD player. Start with a high-quality original.
  2. Use an audio extractor (often called a CD-ripper) to create a digital version of the audio file on your computer.
  3. Convert the digital version of the audio file into an audio format you wish to stream. Note that some audio extractors can convert CDDA files directly into web-appropriate audio formats. If this isn't an option, use an extractor to go from CDDA to .wav, then use an encoder to convert the .wav file to one of the above formats.
  4. Use a text editor to create metafiles that give information on the audio files. In the above examples, my links to audio streams point to small, format-appropriate text files (.ram for RealAudio, .m3u for mp3 and ogg vorbis, and .wax for Windows) that in turn point to the actual audio files.
  5. Post your audio files and metafiles to a web server.
    • If you wish to keep visitors from accessing your audio files without visiting your website, set permissions for the folder which holds your audio to Owner RWX, Group X, and Other X: chmod 711. If this makes no sense to you, read A quick and dirty chmod Tutorial.
    • If you wish to keep other web developers from linking directly to your audio files from links on their pages, include the following lines in your .htaccess file:

      RewriteEngine on
      RewriteCond %{HTTP_REFERER} !^$
      RewriteCond %{HTTP_REFERER} !^http://(www\.)?yourdomain.com/.*$ [NC]
      RewriteCond %{HTTP_REFERER) !^http://www.yourdomain.com/.*$ [NC]
      RewriteRule .*\.(ram|rm|m3u|ogg|wax|wma)$ - [F]

      Substitute your own domain where it says yourdomain above. If this makes no sense to you, read the Comprehensive guide to .htaccess.
  6. Link to the metafiles from a web page, e.g., a href="Town_and_Country_ogg_45kbps.m3u".
  7. Test your files in a variety of audio players.

How I Prepared RealAudio Files

  1. I extracted a .wav file from the CD with CDR Tools Front End (which uses the cdda2wav application), quality set to maximum.
  2. I used Helix Producer Basic to create the .rm file. Settings:
    • Audio Mode: Music
    • Video Mode: No Video
    • High Quality Resampler for Audio: Checked
    • Audience: I set Audience first to 56K Dial-up (34 kbps) only, and encoded a .rm file, then to 256K DSL or Cable (225 kbps) only, and encoded a second .rm file.
  3. I used my favorite text editor, EditPad Lite, to create .ram metafiles.

How I Prepared mp3 Files

  1. I downloaded Exact Audio Copy and installed it using the Quickstart Manual for EAC and Lame from The Coaster Factory.
  2. I started EAC and selected Action, then Test and Copy Selected Tracks, then Compressed, first with the settings on High (192kbps), then Low (128kbps). Settings are found under EAC, Compression Options, External Compression.
  3. For the lower quality mp3 files, I extracted a .wav file from the CD with CDR Tools Front End (which uses the cdda2wav application), quality set to maximum.
  4. I converted the .wav to mp3 with CDex, set first at 64kbps (VBR default, Bitrate Min 48kbps/Max 80kbps), then 32kbps (VBR default, Bitrate Min 32kbps/Max 40kbps). Like EAC, CDex employs the LAME encoding engine to convert WAV files to mp3.
  5. I used my favorite text editor, EditPad Lite, to create the .m3u metafiles.

How I Prepared Ogg Vorbis Files

  1. I extracted .wav file from the CD with CDR Tools Front End (which uses the cdda2wav application), quality set to maximum.
  2. I converted the .wav to Ogg Vorbis with CDex. To change from the LAME encoder (the CDex default) to the Ogg Vorbis encoder, I selected Options, then Settings, then Encoder, then Ogg Vorbis DLL Encoder.
  3. Before converting the .wav file to a compressed audio file (in this case, Ogg Vorbis), I set the Quality slide control to -1.00 (45kbps), then 0.00 (64kbps), then 3.00 (112kbps), then 6.00 (192kbps).
  4. I used my favorite text editor, EditPad Lite, to create the .m3u files.

How I Prepared Windows Media Files

  1. I extracted a .wav file from the CD with CDR Tools Front End (which uses the cdda2wav application), quality set to maximum.
  2. I selected the Convert a file Wizard, set my source file and destination folder, selected Web server (progressive download), then FM quality audio (CBR). I repeated the process with CD quality audio (CBR) for each song.
  3. I used my favorite text editor, EditPad Lite, to create the .wax files.

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