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The making of “piracy standards”
Published in Hendrik Storstein Spilker, Digital Music Distribution, 2017
In the usual accounts, MP3 is described as a compression technique that reduces the size of a music file to between one tenth and one twelfth of its original size without a recognizable loss of sound quality, which is accomplished by simply removing the frequencies that ordinary people cannot hear anyway. This is an account with enough accuracy for most occasions – and one that makes MP3 seem to be the obvious solution. However, as Sterne’s (2006, 2012) detailed accounts reveal, it took Fraunhofer years of research into psychoacoustics and information processing to reach the algorithms. Moreover, negotiations, compromises and modifications in the MPEG group among the 13 other suggestions took even more years. At one point, Audio Layer 3 was almost discarded because of problems with the encoding procedures, which would cause “considerable implementation costs. So much so that, at that time, many considered Layer III as impractical” (Chiariglione 2011a: 2). Audio Layer 3 was finally approved in November 1991.
The History of Audio: It Helps to Know Where You Came From
Published in Timothy A. Dittmar, Audio Engineering 101, 2013
File compression is meant to be transparent; however, if a file such as an MP3 is compressed below a certain limit, these gaps will be noticeable. A high-quality MP3 bit rate would be 256–320 kbps and a low-quality MP3 would be in the 100 kbps range. One of the biggest arguments against using lossy files is that once you compress the file down, you are unable to recapture the original information that was discarded. The advantage of using a lossy over a lossless format is that a lossy format provides a much smaller audio file. Lossy files are helpful when sending a large number of audio files by e-mail, or uploading audio or video to the internet. Lossy files are not intended for storing final mixes or high-quality audio files.
Podcast Production
Published in Michael W. Geoghegan, Greg Cangialosi, Ryan Irelan, Tim Bourquin, Colette Vogele, Podcast Academy™: The Business Podcasting Book, 2012
The final MP3 file that you deliver will have to be encoded from your original edited file. Normally, you can do this straight from your editing software. Most programs allow you to export as MP3. I won’t get into the technical details, but suffice to know that how you encode your file will have a huge impact on the audio quality, file size, and the amount of bandwidth you consume distributing that file to your subscribers. Table 7.7 provides some general guidelines, and you should review it with your podcast professional or the technical person in your team. Please note that this assumes that your podcast consists mostly of voice and only a little music.
Feature Selection for Supervised Learning and Compression
Published in Applied Artificial Intelligence, 2022
Phillip Taylor, Nathan Griffiths, Vince Hall, Zhou Xu, Alex Mouzakitis
Although lossless compression guarantees that the decompressed stream is the same as the original, lossy compression relaxes this constraint and aims only to minimize information loss. In particular, lossy compression aims to keep information where it is important and lose information where its loss will not be noticed. In MP3 audio compression, for example, the high frequencies above the human hearing range are removed. For vehicle telemetry data, similar components of the signals can be removed if they are not useful to further analysis. Some signals such as vehicle speed, for example, contain noise that may even be detrimental to analyses. Such approaches to separating informative and noise components of signals include the discrete wavelet transforms (DWT) (Addison 2017), the discrete Fourier transform (DFT) (Bailey and Swarztrauber 1994), the discrete cosine transforms (DCT) (Ahmed, Natarajan, and Rao 1974).
Detection of AAC compression using MDCT-based features and supervised learning
Published in Journal of Experimental & Theoretical Artificial Intelligence, 2022
José Juan García-Hernández, Wilfrido Gómez-Flores
Currently, the MPEG Audio Layer 3 (MP3) is the most popular format for compressed audio. Thus, it is quite often to find malicious procedures to tamper MP3 audio format by decompressing it into the temporal domain, then operating various types of attacks, and recompressing the manipulated signal to MP3 format (Ren et al., 2016). Also, the lossy compressed audio can be recorded in the same format at a higher bitrate.