[MLA] Fwd: iOS 11 Music app normalisation now uses floating point target

[Bob Katz]

We had some similar information from the developer of iTunes in our 
correspondence years ago. afinfo tantalizingly tells us a little about 
the measurements of the music.

Personally I hope that Apple changes over to R128-style analysis. Though 
who knows? Maybe they know something that we don't know by incorporating 
some short term peak information into their calculations for sound check.

My biggest wish is for Apple to start normalizing Beats Radio (Apple 
Music) ASAP! My clients are so confused when I tell them that Spotify 
will normalize but Apple won't etc. etc. etc.


Bob



On 9/7/17 8:49 AM, Grimm | Eelco wrote:
> ft Channel, in milliseconds from file start
> 10. Position of Max Sample Peak, Right Channel, in milliseconds from 
> file start
>
> All values are stored as a single string in 8-digit HEX format in the 
> file metadata but they can be viewed as decimal numbers (not dB 
> values) via Terminal with afinfo command.
>
> For RMS values 1 to 4, an EQ curve somewhat similar to ISO 223 is used 
> for the frequency weighting.
>
> The file is adjusted by searching the maximum single value of 1 and 2, 
> and attenuated accordingly if the values 7 or 8 would exceed 0dBfs for 
> wav file extension and -1 dBFS for the m4a file extension (even for 
> Apple Lossless encoding) after the adjustment of 1 and 2.
>
> The max perceived loudness values (3&4) and the location values (5,6 
> and 9,10) do not affect the adjustment.
>
> This test was done by setting the values 7 and 8 to zero, so that the 
> player doesn't attenuate by the sample peak values.
>
> All the best,
> Mikko
>
>
>
>
>
>
>
> 2017-09-06 23:58 GMT+03:00 Eelco Grimm <eelco.grimm at hku.nl 
> <mailto:eelco.grimm at hku.nl>>:
>
>     Dear Mikko,
>
>     Great catch!
>
>     Can you explain what you mean with  "It is only possible to adjust
>     a file within -12 to +12 dB's."? Which adjustment is that?
>
>     And I figure that your implementation idea would be to just have a
>     +7 dB offset for -23 LUFS material in the streaming app. But of
>     course this will lead to clipping as soon as users turn up the
>     volume and peaks on the original program are louder than -7 dBFS.
>     Mark that I am not sure if this is a very bad thing (it only
>     happens when people play very loud and in that case the ear buds
>     will already distort a lot...), but if possible a limiter would be
>     more elegant.
>
>     All the best,
>     Eelco
>
>>     I am running Apple's iOS 11 Beta on my phone, and I discovered
>>     that the manufacturer has made a good step in loudness
>>     normalisation architecture.
>>
>>     I have understood that previous versions of the iOS operating
>>     system have used fixed point architecture and therefore it was
>>     important to not exceed peaks before the device volume control
>>     stage. Thi
>

-- 

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 <http://www.digido.com/> No trees were killed in the sending of 
this message. However a large number of electrons were terribly 
inconvenienced.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://grimmaudio.nl/pipermail/mla_grimmaudio.nl/attachments/20170908/fdea8ba5/attachment.html>