Line #9 Platform/MP3


1	[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/mp3_logo.png]]
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3	Unless you've been living away from civilization (or unless you're an old man who steadfastly believes [[NewTechnologyIsEvil Computers Are Bad]], in which case, what are you doing ''here'' of all places?), chances are you've at least heard about [=MP3=]. We see it everywhere on the Internet, our portable music players use [=MP3=] audio instead of those good ol' cassettes, all phones can play audio encoded in the [=MP3=] format, the street dealers from around the block probably sell [=DVDs=] packed with songs in [=MP3=], and your car's sound system can probably play [=MP3s=] from your [=iPod=], CD, or a USB drive.
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5	[=MP3=], more than a simple audio format, is a ''[[{{Technobabble}} lossy, frequency-domain, quantized audio compression algorithm]].'' The name is short for ''MPEG-1 Audio Layer 3'', where MPEG[[note]]Motion Pictures Expert Group[[/note]] is a group of companies developing these sorts of audio and video compression methods. In English: [=MP3=] is a list of step by step instructions that can be followed by a computer program (algorithm) that takes an uncompressed audio file, typically of the same format used in an audio CD, cuts the waveform into about 40 split-second snippets for each second, calculates the frequency components of each snippet (the frequency domain), uses these components to remove parts of the information contained in the sequence (some information is lost in the process -- hence ''lossy''), rounds up the frequency components to some pre-defined values (quantizes them), and encodes the resulting information in a way that takes up less space than the original audio file (compresses it). So far, nothing unusual: There's many other lossy audio compression techniques out there, and many of them already existed in 1994, when the [=MP3=] format was released.
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7	However, there's one difference between [=MP3=] and the other formats of the day: The part that removes information from the sound sequence was specially designed to remove only the sounds the human ear and brain can't hear. This is due to something known as ''psychoacoustics''. Basically, this means we don't hear a soundwave exactly as it comes out of an audio source: our ear is much more sensitive to medium-frequency sounds than it is to bass and treble sounds, and our mind subconsciously filters out the background noise and amplifies the ones we want to hear. This is why you can't seem to hear anything when you record a video in a classroom: your mind filters out the classroom's chatter and lets you focus on your friend's voice, but the microphone can't do this, and just picks up all the environmental sound, allowing more precise representation of the frequencies that are not dropped.
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9	So, to continue the [[OverlyLongGag analogy]] started on their pages: if a Platform/{{MIDI}} file is just sheet music, a [[Platform/WavAudio WAV file]] is an entire orchestra, an [=MP3=] is half an orchestra. You know all the pianos and clarinets and timpanis and stuff that aren't being used by this song? [=MP3=] leaves 'em behind.
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11	Thanks to its psychoacoustic model, [=MP3=]-encoding can strip a ''lot'' of this information from the audio, and yet it still sounds pretty much the same as the original source to most people. As a result, a medium-quality song encoded into [=MP3=] takes up very little space -- usually 4 MB [[note]]A 4-minute song on 128 kbps [=MP3=], very close to CD-quality audio, weighs in at 3.75 MB; 192 kbps, which takes a trained ear to distinguish from CD audio, is only half again as large[[/note]], ''much'' less than the 30-60 MB they usually take on a CD. Back in 1995, when hard disk capacity and internet bandwidth were at a very great premium (modems rarely went beyond 28 kbps, and a CD could hold ''two medium hard drives''), an audio format that could turn a massive file into a very small file was obviously the best choice to save your songs. Another very important reason is that [=MP3=] decoders are very efficient: they use very little [[UsefulNotes/CentralProcessingUnit CPU]] time and very little memory, and can run on very small hardware, e.g. a computer from 1994, a portable [=MP3=] player, a mobile phone, or a gaming console. Of course, the intertubes and the earliest file sharing networks (Napster, Audiogalaxy, Kazaa), and the marketing of the [=iPod=] as a fashionable device played a very big part in [=MP3=]'s popularity.
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13	There are many other compression formats out there, some of them born out of legal conflicts between patents and free/open-source software, some of them are actually better, some of them lossless (where no information is lost, quality is nigh-perfect, but the files are large, albeit not as large as raw audio). As of the 2010's, [=MP3=] is still the most popular audio format in the world. However, FLAC, a Lossless audio format, has been trending upwards among consumers because the speakers in headphones are able to make use of the benefits of FLAC playback, making it the choice for audiophiles.
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15	On April 23, 2017, Fraunhofer IIS/Technicolor, the inventor of the [=MP3=] format, [[https://www.iis.fraunhofer.de/en/ff/amm/prod/audiocodec/audiocodecs/mp3.html have announced]] that the [=MP3=] licensing program has ended due to various patents on [=MP3=] having expired worldwide (including the US), making the format royalty-free. However, do note that several patents reliant on the [=MP3=] containers still hasn’t expired, and one particular patent has been determined to be held by a patent troll. This means while the principles and algorithms of encoding and decoding [=MP3=] files itself are now public domain, the container format still isn’t. This means that while it’s okay to use [=MP3=] audio as an audio stream in, say, a Matroska video file or Ogg audio file, it is still not okay to use the [=MP3=] file container itself.
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17	Interesting note: the original testing of the [=MP3=] algorithms was done with "Tom's Diner" by Music/SuzanneVega (the original acoustic version, not the hit remix by [[https://en.wikipedia.org/wiki/DNA_(duo) DNA]].)

Context Platform / MP3