[MLA] Loudness example with distortion on Sound Check

[Kevin Gross]

It could be up to 3 dB for the difference between dBFS and dBTP and then a
couple more on top of that for codec behavior.

Kevin Gross - AVA Networks


On Sun, Oct 14, 2018 at 9:12 PM Bob Katz <bobkatz at digido.com> wrote:

> In that case you are advocating a fixed attenuation (1 dB, 2 dB?) across
> the board. I would certainly accept that. I wonder if Spotify will?
>
>
> Bob
>
>
>
>
> On 10/14/18 10:09 PM, Kevin Gross wrote:
>
> To fix this all you need to do is attenuate the floating-point output of
> the decoder by a couple or few dB before you convert to fixed. The playback
> will be a little quieter but the listener can compensate by adjusting the
> volume up. The same attenuation is applied to all material at all times so
> there's no anticipation or other monkey business. For efficiency, this
> adjustment can be combined with the loudness normalization adjustment.
>
> Kevin Gross - AVA Networks
>
>
> On Sun, Oct 14, 2018 at 7:23 PM Bob Katz <bobkatz at digido.com> wrote:
>
>> Dear Kevin: Admittedly, there is no one size fits all encoding level. But
>> if content producers (mastering engineers) shoot for iTunes' MFIT (high bit
>> rate) codec, the vast majority of clipping in all streaming will be handled
>> fairly well in my opinion. I personally don't shiv a git if it's
>> occasionally too hot for Spotify if we cover MFIT in our coding of a
>> master. Spotify deserves what they get with such a low bit rate codec they
>> use, and that will improve in due time. As a mastering engineer I do not
>> want to shoot for lowest common denominator. And most of my
>> sensibly-mastered material will play fine on Spotify with possibly only
>> occasional one hit clips. As I've said before, it's impractical to make and
>> control too many masters. We're currently lobbying for all distributors to
>> send the 2444 MFIT master and send it to all the streaming customers. We'd
>> like to see the 1644 originally intended to send to CD die a quick death.
>> That's often a dB hotter than the MFIT master.
>>
>> As for attacking both ends and dealing with clipping on the decode side
>> I'd like to hear an explanation as to how a streaming service's player can
>> deal with (anticipate) a clipping situation and attenuate post decoder....
>> from a moving bitstream. Please start by telling us how you would deal with
>> a song that has a clip two minutes after the song has already begun...
>>
>> Best wishes,
>>
>>
>>
>> Bob
>>
>>
>> On 10/14/18 6:54 PM, Kevin Gross wrote:
>>
>>
>> On Sun, Oct 14, 2018 at 8:32 AM Bob Katz <bobkatz at digido.com> wrote:
>>
>>>
>>> In our recent conversations, I pointed out that it's totally impractical
>>> to expect or even talk about any streaming player applying attenuation to
>>> avoid overs just post the decode stage. Therefore even though the clipping
>>> is not baked into a well-made encoder, it has to be the responsibility of
>>> the mastering engineer to prevent decoder clipping by reducing the level
>>> that will be applied to the encoder if necessary. Mastering engineers have
>>> to bake that level into the fixed point file that we supply to the
>>> distributors.
>>>
>>
>> If you want to fix this pre-encoder, you're going to get content
>> producers to comply with something like Spotify's -2 dBTP suggestion. That
>> means bringing peaks down 4-6 dB compared to where they currently stand at
>> 0 dBFS. I don't see mastering engineers getting behind this. I don't know
>> if we even want to recommend it either because it will result in more
>> squashing.
>>
>> We should also be raising awareness of the potential for clipping
>> post-encoder and advocating for more robustness in players in this regard.
>> You're right, we're not going to be able to get all decoders fixed. We're
>> also not going to be able to get all masters fixed. If we work both ends,
>> we'll make the most meaningful progress.
>>
>> Kevin
>>
>>
>> --
>>
>>
>> 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.
>>
>>
> --
>
>
> 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.
>
>
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