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Opus, AAC, Vorbis, MP3, MPC at 128 kbit/s

Opus, AAC, Vorbis, MP3, MPC at 128 kbit/s

This listening test has almost the same codec contenders as the previous @96 one with the following differences:

  • All encoders have integer/discrete quality settings which are normally used in practice; in other words, quality parameters were not adjusted to get equal resulting bitrates with nine SE test samples; so the test will show how these codecs with usual settings compare with each other; for codecs with close resulting bitrates some conclusions about their efficiency can be derived as well
  • Opus version was updated from 1.0.2 to 1.1 with some quality fixes
  • CoreAudioToolbox for QuikTime encoder was updated to without any quality improvements
  • AAC encoder by Fraunhofer from Winamp was updated from 1.04 to 1.08
  • New AAC encoder by Fraunhofer from Android Open Source Project was added
  • Musepack MPC was added


Resulting list of contenders:

AAC VBR@112.0 (Winamp 5.666) - VBR, AAC LC

  • AAC Encoder v1.08 (Fraunhofer IIS) from Winamp 5.666: Variable Bitrate, Preset 4
  • The encoder is also available as CLI utility and can be downloaded from

AAC VBR@118.4 (iTunes 11.1.3) - TrueVBR, AAC LC

  • iTunes or QuickTime 7.7.4 AAC Encoder via qaac 2.30 (CoreAudioToolbox qaac -V63 ref.wav
  • The encoder is included in such Apple products as iTunes, QuickTime, Safari; though not all of its features can be reached through these applications. For greater flexibility the CLI utility qaac can be used
  • download from

AAC VBR@117.5 (NeroRef 1540) - CVBR, AAC LC

Vorbis VBR@119.4 (Xiph 1.3.3)

Opus VBR@115.7 (libopus 1.1)

  • encode: opusenc --bitrate 96 ref48.wav (44.1/16 -> 48/24 by Audition CS6)
  • The encoder operates at 48kHz only, so for other sample rates (as in our case) resampling is required. Some good quality resampler is already integrated into the codec but we used the external one from Audition CS6; the complete test files production chain: reference test files 44.1/16 -->> 48/24(Audition CS6) -->> opusenc -->> decode by foobar2000(48/32) -->> 44.1/32(Audition CS6) -->> test files production
  • download from

mp3 VBR@113.7 (Lame 3.99.5) - MPEG-1 Layer 3, VBR

AAC VBR@110.9 (libfdk 3.4.12) - MPEG-4 AAC LC, VBR mpc VBR@123.3 (SV8) - Musepack


In addition to usual live ratings on 128kbit/s page there will be detailed results of this test when corresponding ratings reach 1% accuracy (example of the detailed report is in the previous 96 kbit/s listening test).


SoundExpert reminds you that final conclusion about audio quality of any device added can be made only after finishing corresponding listening test. So we encourage you to take part in testing. SE ratings exist only thanks to visitors like you. Testing is short and easy, visit our Testing Room for simple 1-2-3 instruction.

Please, remember, downloading test files from SoundExpert you will not necessarily get the ones of the newly added codecs. SoundExpert testing is blind testing – you don't know the device you test. This is the only reliable way of getting true audio quality ratings, free from any cheating and various human senses other than perception of sound quality. After you have sent your grade you will see the device you tested.

Best regards,
SE Team.

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What is SoundExpert

SoundExpert - How it works SoundExpert (SE) is a crowdtesting service that provides audio quality ratings of sound equipment and technologies such as mp3, aac, wma ... encoders, portable players, sound cards, amplifiers ...

The ratings are based solely on results of blind listening tests when listeners don't know the particular device they test. So the values are completely unbiased and free from any marketing and advertising noise.

SoundExpert provides ratings thanks to visitors who take part in testing. The more number of participants - the more devices and technologies could be tested. The ratings are computed in real time while new grades are returned by visitors. The testing procedure is simple and short enough that anyone, including you, can participate. Just download a test file (<3Mb), listen it (<15s) and send back your judgment. Details are in test file. The more accurate grades - the more reliable ratings.

SoundExpert is independent non-commercial research project. It's in beta state because it uses new audio metrics and corresponding listening test design which are not widely adopted by audio engineers. The key feature of this new method is possibility to hear sound artifacts which are normally beyond threshold of human perception. So, please, use these ratings with caution. Detailed but still easy to understand explanation of SE internal mechanics is in the article "SoundExpert - How it works".

The main idea behind this service is consumer control over sound quality measurements of various audio equipment on the market. SE, being a distributed human project, combines tiny efforts of audio enthusiasts for carrying out this task.