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Apple Music Announces Spatial Audio and Lossless Audio

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Re: Apple Music Announces Spatial Audio and Lossless Audio

#501

Post by Grustaf »

alanbernstein wrote: post #454
coliveira wrote: post #421

Earlier quoted context omitted.

To start replicating the sound of an orchestra, you'll at a minimum need one speaker at each location where a player is, playing a single channel (the instrument). But even this is simplifying things, because each instrument has a different body shape, different sound projection, which would need to be replicated by specialized speakers. Also, the room has an important effect on how the sound waves travel and hit you…

What if you only want to replicate the sound of an orchestra as heard by an observer at a specified point ? Why wouldn't two microphones be sufficient? That's how it's perceived, after all.

You can get really nice sound that way, but to get the full effect you need to take into account the shape of the head and ears of the listener. After all, these are important factors that help us place sound in space.

https://en.wikipedia.org/wiki/Head-related_transfer_function

Re: Apple Music Announces Spatial Audio and Lossless Audio

#502

Post by solarmist »

robotresearcher wrote: post #264
dagmx wrote: post #162

Earlier quoted context omitted.

Yeah, our eyesight is not very good without that saccade motion.

Below some movement threshold you go completely blind in just a few seconds. One of the standard stare-at-the-dot-machine optometry tests is enough to make my vision start to gray out.

Yeah, your body adjusts to stimulus very quickly to minimize it.

Re: Apple Music Announces Spatial Audio and Lossless Audio

#503

Post by INTPenis »

alfalfasprout wrote: post #38
cies wrote: post #23

From the article: > J Balvin said: [...] With Lossless, everything in the music is going to sound bigger and stronger but more importantly, it will be better quality. [...] There have been tests showing we cannot hear the difference between minimally lossy audio (e.g. mp3 320kbps) and lossless. But Balvin can. And it sounds "bigger and stronger". The extra quality of lossless is nice when mixing/remixing the sound, a…

> There have been tests showing we cannot hear the difference between minimally lossy audio (e.g. mp3 320kbps) and lossless. But Balvin can. And it sounds "bigger and stronger". On the contrary, you can actually do these tests yourself ( https://www.npr.org/sections/therecord/2015/06/02/411473508/... ). I and many others running good high end gear can repeatedly score well on these tests. Of course, it's not only the…

That test was amazing. You made me really excited and I even guessed the first one correctly by seemingly hearing the difference. So I spent minutes on each of the other questions, listening and listening, but I just couldn't hear it and sure enough I guessed wrong on every other question after that.

And I have a mid-range mini amp that fits in between my books, and two mid-range dali speakers hooked up with a regular 3.5mm outlet to my Ryzen MSI PC board, volume up to max on the computer but not on the amp.

Re: Apple Music Announces Spatial Audio and Lossless Audio

#505

Post by gomox »

alanbernstein wrote: post #454
coliveira wrote: post #421

Earlier quoted context omitted.

To start replicating the sound of an orchestra, you'll at a minimum need one speaker at each location where a player is, playing a single channel (the instrument). But even this is simplifying things, because each instrument has a different body shape, different sound projection, which would need to be replicated by specialized speakers. Also, the room has an important effect on how the sound waves travel and hit you…

What if you only want to replicate the sound of an orchestra as heard by an observer at a specified point ? Why wouldn't two microphones be sufficient? That's how it's perceived, after all.

Your ears are highly directional devices and an orchestra in a concert hall creates a highly complex soundscape that is impossible to replicate with 2 channels. Location awareness (i.e. 2 mics where your ears are) is just a small part of the problem.

Re: Apple Music Announces Spatial Audio and Lossless Audio

#506

Post by solarmist »

falcolas wrote: post #170
solarmist wrote: post #108

Earlier quoted context omitted.

Sure, but commercial spatial audio is in its infancy. We’re maybe in the 1920’s if you compare it to video. So as the techniques expands and people adjust and both sides gain experience we’ll be able to compensate for the perceived shortcomings by exaggerating effectively to make it seem better than our natural spacial hearing.

Fair warning, any attempts in this area will have to take your individual ear shape into account to be accurate. Our brains have learned how sounds change based on the frequency changes due to our individual ear shapes, and any software that wants to emulate true spatial sound will have to take this into account.

Sure, but I'd bet that accounting for a handful of shapes (maybe less than 10) could cover 90% of the differences. We've applied that principle to everything else in the body pretty well so far. It will take a good bit of time to figure out what those shapes might be though.

Re: Apple Music Announces Spatial Audio and Lossless Audio

#507

Post by lozf »

yingbo wrote: post #290
moogly wrote: post #175

Earlier quoted context omitted.

> The format is ALAC, it’s not proprietary but an open spec True. No one else bothers with it though, because why should they when FLAC exists? That makes ALAC, in practice, largely an Apple-only format.

As mentioned above, ALAC is an open source format, which has all benefits as other open source format e.g. FLAC.

Apple created ALAC as a closed source project after FLAC had already been released as Open Source. They subsequently changed ALACs license to Open Source -- presumably to take advantage of further development from the community.

Re: Apple Music Announces Spatial Audio and Lossless Audio

#508

Post by beefman »

est31 wrote: post #378
beefman wrote: post #367

Earlier quoted context omitted.

Do we know how Apple's Spatial Audio works? And what is its relationship to Atmos?

Dolby Atmos allows you to specify multiple channels together with spatial metadata. The Ambisonics support for opus is quite similar. The spec allows the encoder to specify an arbitrary matrix used for mixing of the audio. If you read Apple's blog post, it seems they use the Dolby Atmos format instead of their own homegrown solution.

Doing some reading just now, it seems Atmos is what's called an OBA (object-based audio) format. It's fundamentally lower-level than Ambisonics, which falls into the SBA (scene-based audio) category, so it should be possible to mix it down to Ambisonics. In fact I suspect the Atmos decoder does something like that on its way to creating signals for each speaker. OBA formats generally require more bandwidth than SBA formats. The benefit is that the end user can customize the mix (e.g. mute certain sources). In the case where there are many mutually-exclusive objects (e.g. dialog in different languages), the bandwidth advantage of SBA diminishes...

Re: Apple Music Announces Spatial Audio and Lossless Audio

#509

Post by olilarkin »

Here is a dance music track originally mixed in 5th order ambisonics, decoded to a dolby atmos "bed" that you can try with the airpod pros. The audio has lost some fidelity and it would be better to mix direct to atmos in this case. I look forward to hearing some professional atmos mixes on apple music when this launches!

https://twitter.com/olilarkin/status/1353171949204221953?s=2...

Re: Apple Music Announces Spatial Audio and Lossless Audio

#510

Post by gevz »

sbaildon wrote: post #249

Apple can add feature after feature, but if Music continues to split albums without warning, it's close to useless. I can't curate a music library when I can't rely on my music not being jumbled around. Dropping music for licensing issues is one thing, but messing with metadata is beyond frustrating. For arbitrary reasons, Apple Music will: remove songs from albums and re-add them to your library as the "single" or "…

I wonder if it is specific to the country. I am accessing the US store and out of all link you posted I have no issues. All EPs and albums are complete and no tracks are missing.
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