Let's open another can of worms — are music streaming services providing genuinely lossless audio?

[Currawong]

On 3/8/2024 at 5:14 PM, yamamoto2002 said:

I'm not surprised if they alter original PCM data to add audio watermark on PCM stream to track down which user illegally redistribute it to pirate sites

The major labels used to, and it was audible. I don't know what caused them to change it, but probably that TIDAL and Qobuz couldn't advertise their music as lossless if the originals had been altered.

[Currawong]

Lossless has a hard definition: That the music hasn't been altered irreversibly from the master recordings (of which there may be multiple)* at the bit-level.

 

That's as succinctly as I can put it, so it bears a bit of expansion. 

 

Irreversible alteration would mean that either lossy compression has been applied (for MP3, AAC and MQA), watermarking, or that some kind of post-processing or EQ is applied, such as volume levelling. This can equally be applied to the original digital file, or done on the fly by software or hardware.

 

So, the question really is: Are music services using the same digital music files as you'd get on, say, a CD, or buy from HDTracks, Linn, NativeDSD or elsewhere?  Then, given peoples' experiences with the sound seeming to be different from a CD than from a streamed track, is that really the result of the files being different, or is something going on with the software or hardware in their system (eg: volume levelling, re-sampling, or hardware noise levels) to make an audible difference?

 

If we consider the former, that a streamed track is not a bit-perfect match to a CD, is it because it's at a different sample rate? If it is 16/44.1, then is it from a newer or older master of the same album? Are both the CD and streamed versions exactly the same length? If not, that would cause a checksum comparison to fail, but still result in a flat output from an audio diff comparison if the samples are aligned correctly. 

 

I don't think that there will be a straight-forward answer to all these questions, and it has to be considered for each individual album. Some famous albums have numerous versions now. Albums on streaming services seem to be constantly deleted and replaced, without any explanation as to why.

 

*Ie: There may be multiple masters at different sample rates, and also masters for particular formats, eg: radio, though I'm not sure how common this is now.

[Currawong]

On 3/13/2024 at 5:16 AM, Norton said:

But is that a hard definition, and if so , whose?  And indeed what do we mean by a Master recording and the implied provenance, if  there can be multiple masters?   For example, if a 70s analogue  recording is transferred by the record company to 24/96 and then distributed as RBCD as a “remaster” and I then make a bit perfect rip of that CD, can I be said to have a lossless copy of the original analogue master?  I’d suggest not and that, far from a hard definition, lossless is just a meaningless  marketing term 

I probably should have specifically said the digital original in my definition, but it was assumed. Indeed though, analog-to-digital conversion is a major issue. For example, Miles Davis' Kind of Blue was transferred poorly (the timing was wrong, for a start!) and this plagued all the digital masters until HDTracks managed to get hold of the original tapes and do a new transfer.