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An odd mp3 file that i've had for ages that suddenly did not play in ffmpeg anymore (and still played fine everywhere else) made me delve up an obscure bit of internet knownledge

https://forum.audacityteam.org/t/cannot-recognise-certain-wav-files/36506/7

Apparantly back in the day before windows tools like internet explorer and powerpoint supported MP3's natively people used to put them in a RIFF container (i.e. the container used by WAV files) with an encoding of "MP3".

Due to the way MP3 files work a "dumb" mp3 player would play right past the header of a WAV file and start playing these pseudo-MP3 files just fine, but windows tools would think these were WAV files, decode them with the right codec, and play them fine too.

Anyways (if my theory is correct) what happened here is that an ID3 tag was added to such a RIFF MP3 file, making for truly an accumulation of weird formats of questionable legality that only worked because most mp3 players work on a basis of "best of".

Mp3 sure is one of the formats of all time...
It's a screenshot of a hex edit…
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And for those curious: yes this is a real mp3 file; it starts ejecting frames starting with FF FB right after the RIFF header. That's all a dumb mp3 player looks for btw; headers are completely optional
It is a second screenshot of th…
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