Where the audio file is going

In 2019 I wrote that we would go back to lossless. We did, and in a way I would not have guessed at the time: not through discs and cables, but inside the very apps that had built their fortune on compression. Let me pick the piece up where it started, because the story still holds.

Tom's Diner by Suzanne Vega is the first song an mp3 ever "listened to". It was not a random test file: Karlheinz Brandenburg and the team at the Fraunhofer Institute in Erlangen, who had been working on the codec since 1987, used that a cappella voice to tune the algorithm. If the naked voice came out damaged, they went back to the drawing board. The standard arrived in 1993, the .mp3 extension in 1995.

The revolution was keeping good quality while cutting the file to a tenth of its size, by throwing away what the ear should not notice: sounds masked by other sounds, covered frequencies, tails nobody perceives. "Should not" is the right phrase, because somebody went and listened to exactly what was being thrown away. In 2015 Ryan Maguire, then a PhD candidate at the University of Virginia, took Tom's Diner, compressed it at 128 kbps and reassembled only the discarded sounds. The result is called moDernisT, an anagram of Tom's Diner, and it is the ghost track you can hear below.

Over the years the encoding improved to the point where a 320 kbps mp3 is almost indistinguishable from the original. Then the patents ran out: in Europe in 2012, in the United States on 16 April 2017, and a week later Technicolor and Fraunhofer shut down the licensing programme. The headlines announced "the death of the mp3". Nonsense: a format dies when people stop using it, as happened to cassettes and VHS, not when a patent expires. Fraunhofer, meanwhile, had long moved its research on to more efficient codecs such as AAC and MPEG-H.

The same thing had happened to the GIF: the patent on its compression algorithm (LZW, held by Unisys) expired in June 2003 in the United States and in 2004 in Europe, and since then GIFs have become a language. The 2019 version of this piece said 2007. It was wrong.

The other codecs

Many others were born alongside the mp3. AAC is the default format on YouTube, on Apple's platforms and on most consoles and phones. AC-3 is less familiar by name, but you have heard it in every cinema: it is the algorithm behind Dolby Digital. Microsoft's WMA and the RealAudio of the old RealPlayer (last release in 2006) stayed in the early 2000s, and that is where they belong.

But the principle the mp3 was built on, storage that costs money, was already fading in 2019. Fast connections and big drives let you move huge files around without losing anything. Hence the lossless formats. Apple had its own as early as 2004, ALAC (Apple Lossless): in 2019 I wrote that AAC had replaced it, when in fact Apple open-sourced it in 2011 and put it back at the centre of its catalogue in 2021. FLAC (Free Lossless Audio Codec) is its open equivalent, and the one nearly everyone else uses.

What happened next

The question in the 2019 subtitle was: will music become less and less compressed? Today the catalogues answer it.

• Apple Music has been lossless since June 2021, in ALAC, at no extra cost.
• Amazon Music folded high resolution into its standard subscription the same year.
• Tidal, which had flown the lossless flag from day one, dropped the proprietary MQA format in 2024 and moved entirely to FLAC.
• Spotify, after four years of announcements, switched on lossless in September 2025: 24-bit, 44.1 kHz FLAC, included in Premium.

So yes: the prediction came true, and faster than expected. The compressed file is not dead, but it has stopped being the destination. Today it is the safety net for when the connection is slow.

There is one place, though, where compression has stayed, and it is the last metre. Almost everyone listens on wireless headphones, and classic Bluetooth does not carry a lossless stream: it compresses it again, with codecs such as SBC, AAC, aptX or LDAC. Your subscription sends you a perfect FLAC, and the headphones turn it back into something that resembles a good mp3 a moment before it reaches your ear. Codecs that promise lossless over the air do exist, but they need matching headphones and phone, and in 2026 they are still the exception.

It is the same story as ever, moved one metre along: music takes the shape of the narrowest channel it passes through. In 1993 that was the modem. Today it is the antenna inside an earbud.

This piece is a revision of an article from August 2019. Two dates were corrected (the GIF patent and the fate of ALAC), and Ryan Maguire's ghost track and the streaming story from 2021 to 2025 were added.