Public Multiformat Listening Test @ 128 kbps (December 2005)

Some development happened since the last public multiformat listening test @ 128 kbps conducted by Roberto Amorim. All encoders experienced major or minor updates that should improve audio quality.

The purpose of this test is to find out which popular VBR encoder outputs the best quality on bitrates around 128 kbps.

• Which codecs and settings are tested?

  • Nero AAC 3.1.0.2
    VBR/Stereo - Streaming, 100-120 kbps [LC AAC]
  • iTunes AAC 6.0.1.3
    128 kbps, VBR
  • LAME 3.97 Beta 2
    -V5 --vbr-new
  • Ogg Vorbis AoTuV 4.51 Beta
    -q 4.25
  • WMA Professional 9.1
    Quality-Based VBR, Q50
  • Shine 0.1.4 (Low Anchor)
    -b 128

• Is it normal that the bitrate is very high on some samples (even 180 kbps)?

  Yes, and that is the beauty of VBR encoding - it will simply ignore bitrate limitations whenever possible, using as much bits as needed to encode a problematic sample.

  Although that raises issues of fairness, it is the best way to compare modern codecs that shine most in VBR mode, like MP3 and Vorbis. Trying to force a VBR setting to match a desired bitrate, although fairer, is far from the usual practice of audio encoding, where it's more usual that a user just sticks to a quality setting, not caring much about a specific bitrate.

  The quality settings for the VBR codecs were chosen because they average out to about 128 kbps over a number of encoded albums. It would be unfair to tie the hands of VBR codecs and punish them for being smart about where to spend what turns out to be the same number of bits over the long run.

• Who should take the test?

  Anyone interested in lossy audio quality, or people who have no interest but would like to help making this test better are invited. You don't need excellent hearing, but some good gear is welcome. Headphones are a must-have.

• How do I take the test?

  Download ABC/HR and the readme from the following location:

  • ABC-HR_bin.zip

  If you already have ABC/HR, download the readme from here:

  • readme.txt
  • readme.htm

  Further instructions and links to the sample packages are inside the readme.

• Can I take the test even if I am not running Microsoft Windows?

  Thanks to schnofler, any person running an operating system with Java Runtime Engine 1.4 can participate (JRE 1.5 is recommended, though). Instructions are available inside the ABC/HR package.

• When will the test finish?

  The test is scheduled to end on December 25th, 2005. This date may be extended if proven to be necessary.

  Update 1: The test was extended to end on January 13th, 2006.

  Update 2: The results are now available here.

If you have any questions, feel free to contact me via e-mail: mail@listening-tests....

Best regards,
Sebastian Mares

© Sebastian Mares, 2005 | Layout by Dibrom | Portions of the Text by Roberto Amorim