Dynamic range normalizer
The audio quality of compressed formats such as MP3 or AAC is often perceived as better or at least equivalent to so-called lossless formats or audio CDs even by trained listeners. This is the conclusion reached by the TrustedReview test platform in a blind test with several people.
TrustedReview points out that this is not an experiment with strictly scientific parameters. However, what was remarkable about the results was that the self-reported hi-fi enthusiasts among the test subjects were wrong to recognize the uncompressed piece of music.
Already sophisticated coding
“I am not surprised by this result, because we reached a similar conclusion in our internal experiments. Encoding technologies are now so sophisticated that most people no longer hear any difference even when compressing at a lower data rate,” he explains. Bernhard, MP3 expert at Fraunhofer. Grill in conversation with press release.
“It would even go so far that a properly encoded 192 kbit / s AAC sound file is the best alternative to today’s audio CD, as the 16-bit resolution of the CD can be far exceeded.” For people who are particularly sensitive to audio and want to be absolutely sure, Grill recommends a data rate of 256 kbit / s for AAC and 320 kbit / s for MP3.
The development trend goes in two directions
According to Grill, the current trend in audio encoding is bi-directional. For one thing, it’s about getting even smaller files with low-quality compromises. “This currently plays an important role, especially with streaming services over cellular networks, as bandwidths are still low despite UMTS and retrieval of large amounts of data is still expensive in most countries. “explains Grill. The most promising encoding is the HE – AAC audio codec, also known as AAC +, which is a further development of the AAC standard used by iTunes, for example.
On the other hand, the developers are also targeting the best of music listeners and want to show that with the right encoding technology, even the last noticeable differences from Audio CD can be eliminated. “Meanwhile, record labels and sound engineers have also understood how to encode for excellent sound quality. Another advantage of existing encodings, such as MP3 or AAC, is that the processes behind them are constantly being improved,” he says. Grill. MP3 encoded at 128 kbit / s sounds much better today than 15 years ago.
The term “compression” is misleading
The Fraunhofer MP3 and AAC developers find the term “compression” misleading anyway. “This should not be confused with dynamic compression, that is, the weakening of noisy passages and the elevation of soft passages, which has always been a technological necessity, especially with famous records and in FM broadcasting.” In this regard, MP3 and AAC with dynamic range up to 24 bits are even better than audio CD, which is limited to 16 bits. This restriction is not removed with a lossless copy of an audio CD.
Mp4Gain offers a dynamic range normalize, that is, the weakening of the noisy passages and the elevation of the soft passages, which is the most modern.
Much more important for good sound quality or an attractive sound image is not the medium or file format used, but the speakers used. “These are still the worst adulterers in the entire chain,” says Grill.
