[MLA] Spotify’s plans

[Bob Katz]

On 10/31/19 1:47 PM, Grimm | Eelco wrote:
> Hi,
>
> Sorry for my absence, I was a bit busy...
>
>>> I think it means what it says, normalize PCM audio to -11 LUFS. From 
>>> which I assume, stuff that is louder than -11 LUFS gets digitally 
>>> attenuated. Stuff quieter is untouched before normalization. 
>>> Loudness metadata is stored as usual so that playback target can be 
>>> adjusted.
>
> Right. AFAIK all tracks of an album are attenuated with equal amount.


That's ambiguous, it could mean several things. Please rephrase.





> But mark that this is not yet implemented by Spotify. It is part of 
> their larger plan which also covers moving to BS1770, using the 
> loudest track of the album as anchor for album normalization etc. They 
> are waiting for td1004 for guidance - if we are fast enough.
>
>> "a reduction on material that's >-11 LUFS" improves encoding quality 
>> (subtly) for that material, but there's plenty of lower material 
>> whose peak level would overshoot the codec whose LUFS falls between 
>> about -11 and -16 and occasionally below -16 so there's not enough 
>> forethought going on here. If you're going to attenuate before 
>> encoding in order to prevent encoder clipping then do it right. 
>
> Sure there is material < -11 LUFS that shows intersample peaks and can 
> overload a codec. But there’s much more material > -11 LUFS that does 
> so. If we can get Spotify to abandon their -11 LUFS option, we may 
> nudge them to attenuating to -14 LUFS before encoding, but I would not 
> put my money on that yet. And attenuating to -11 LUFS is better than 
> nothing imo.


You're saying that half a cake is better than none. I'm saying that if 
you have millions upon millions of songs, getting it done right is a 
priority. So if it's not right, keep working until it is, no compromise.




>> With Spotify I always need more clarification, since Spotify's 
>> practice has been to upwardly normalize for streaming.
>>
>
> The ‘attenuate to -11 LUFS’ part just applies to albums with loudest 
> tracks louder than -11 LUFS (these are also the ones that would 
> otherweise clip the codec). Upward normalization is only needed for 
> albums softer than this, so they will be encoded at their original level.
>
> (Ian wrote):
>> I thought they would store 3 separate copies, each hard-normalised to 
>> Loud, Medium or Soft, and then streamed directly.

> I am not 100% certain that Spotify does not apply positive gain and 
> compression in #3, but what I recall is: compression is only used for 
> ‘Loud’ playback at -11 LUFS, and this compression is not performed in 
> the app, but stored on the server.
>

I tagged you in a thread where Sigurd proved using John Cage's "4:33" 
that Spotify upward normalizes and peak limits all three targets. Though 
it would be very rare to find something below -23 LUFS, that extreme 
case proves that the algorithm is in use.


Most important for me is that Andreas was at our meetings and likes to 
contribute and cooperate.


Yes! And we need to keep him involved.



Best,




Bob


-- 

If you want good sound on your album, come to Bob Katz 407-831-0233 
DIGITAL DOMAIN MASTERING STUDIO Author: *Mastering Audio* Digital Domain 
Website <https://www.digido.com/> No trees were killed in the sending of 
this message. However a large number of electrons were terribly 
inconvenienced.

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