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Objectively best/most compliant MP3 decoder?

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#1
I recently found myself going down the rabbit hole of trying to figure out which is the most compliant and bit perfect MP3 decoder available today. Now, I understand the inherent limitations of lossy formats but the stark reality is we largely live in a post-CD era where Amazon and iTunes rule the world. With that in mind, here is the objective tests I found so far endeavoring to show the most bit perfect MP3 decoder and results don’t entirely line up.

This link suggests that Apollo 37zz is the best:
https://web.archive.org/web/20131023220543/http://koti.welho.com/hylinen/apollo/FAQ.html

On the other hand, this source tends to lead one to believe that MAD is the best:
https://www.underbit.com/resources/mpeg/audio/compliance/

Yet here Fraunhofer’s l3dec appears to be the best:
http://mp3decoders.mp3-tech.org/24bit.html

Thoughts?
 

Veri

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For MP3 when I did need it, I just used the latest available LAME at 320kbps constant setting. Had no idea there were so many options..?
 
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#3
For MP3 when I did need it, I just used the latest available LAME at 320kbps constant setting. Had no idea there were so many options..?
To be clear, I am speaking of the decoder or playback part and not the encoder that turns your lossless CD into a compressed lossy MP3, which is what LAME is doing in your case. The strange thing I’ve learned is because of its purported accuracy, there is a cult following of sorts for Apollo and “many radio stations” insist on using it for decoding for broadcast. Until recently, I didn’t even know it existed.
 

Veri

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To be clear, I am speaking of the decoder and not the encoder, which is what LAME is doing in your case. The strange thing I’ve learned is because of its purported accuracy, there is a cult following of sorts for Apollo and “many radio stations” insist on using it for decoding for broadcast. Until recently, I didn’t even know it existed.
Woops, my bad. You're saying these decoders don't all translate to the same PCM output ?
That would be weird to say the least :oops: would be quite simply to verify, too.
 

bennetng

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Woops, my bad. You're saying these decoders don't all translate to the same PCM output ?
That would be weird to say the least :oops: would be quite simply to verify, too.
It's completely true that different decoders decode differently. For fixed-point decoders vs floating-point decoders the differences could be audible when the fixed-point deocders clipped, for floating-point decoders the differences could be measured and identified (e.g. null test) but I can't ABX them.
 

bennetng

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#6

Fluffy

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#7
This sounds like a rabbit hole that should be avoided. If you're not concerning yourself with perfection by listening through lossy compression (and there's nothing wrong about that, I do it too), then why bothering yourself with obsession with decoders?

On top of that, not every service uses MP3. There are many different types of lossy codecs, but they're all transparent at 320 kbps and above (some are transparent below that). I think whatever service you are using, you should just make sure you are getting the best bitrate you can, and that should be the end of it.
 

mansr

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Woops, my bad. You're saying these decoders don't all translate to the same PCM output ?
That would be weird to say the least :oops: would be quite simply to verify, too.
The MP3 spec leaves some wiggle room for decoder implementations. The differences are mainly in the IDCT. While it's possible to be compliant with a 16-bit fixed-point version, using 32-bit or floating-point will be more accurate.

MAD is an excellent decoder and free. Use it with confidence.
 

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