mp3 decoder tests

  Introduction  

This site contains test results on a number of mp3 decoders. Such a test wouldn't be necessary if all decoders worked properly, but unfortunately they don't. In fact the outputs of many popular decoders were found to be incorrect.

It's well known that mp3 encoders can have a significant effect on the sound quality of coded audio. However, the MPEG standard sets out the requirement for a decoder exactly a given MPEG-1 layer 3 stream (typically an .mp3 file on a PC) should always decode to a certain uncompressed digital audio signal (typically a .wav file on a PC). Apart from rounding errors in the last bit (i.e. +1 or -1 on a scale ranging from 32768 to +32767 for 16-bit audio) the output should be exact.

Every decoder should produce the same result. They don't. So, which decoders do produce correct results, and how bad are the ones that don't? Skip to the conclusion to find the answer to the first question, or look at the overall test results for the answer to the second. If you're interested in the details of these tests, read on...