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FLAC 1.4.0 released – added support for 32-bit audio

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Re: FLAC 1.4.0 released – added support for 32-bit audio

#31

Post by squeaky-clean »

atoav wrote: post #5
michaelwww wrote: post #3

After reading "How Music Works" by David Byrne, it seem like FLAC is solving the wrong problem. No one needs over 4 billion discrete levels.

I am a recording engineer and I will choose 32 bits over 24 any day when recording. Of course you need the right (exceptionally good!) preamps to even make a difference here, but when you are manipulating audio 32 bits and upwards (for summing) are the default (for a reason). Having something to store those files with a little bit of lossless compression is a welcome addition

It's very unlikely your audio interface can actually record at 32 bit resolution.

https://www.mojo-audio.com/blog/the-24bit-delusion/

32bit or more makes sense for dsp and summing, and non-musical data storage. But your I/O is most likely not giving 32 bits

Re: FLAC 1.4.0 released – added support for 32-bit audio

#32

Post by jrajav »

klodolph wrote: post #20
Night_Thastus wrote: post #10

I had no idea FLAC didn't store 32-bit. I'll need to look over my library and make sure nothing strange is going on. I'm curious if sites like Qobuz will suddenly replace some of their existing files with higher-bit copies if they already had them and just had no way to encode them as FLAC.

It is extremely hard to justify 32-bit audio from a technical standpoint, since it requires that every component in your audio chain has better than 144 dB dynamic range. In practice, just about none of the analog components in your audio chain will have that kind of dynamic range, and any analog components in the recording chain are unlikely to have that range either. The kind of equipment I'd expect to see in order…

You're absolutely right insofar as you're speaking about static audio that's already been produced and finished - there is almost no point in storing anything above 24-bit integer as far as dynamic range even for archival purposes.

However, there is a legitimate purpose behind having higher dynamic range for production purposes and sample sources. There are some recording sources that can actually produce 32-bit audio. Plus, you might want to do some processing on the sound that would end up affecting the dynamic range, or otherwise benefit from the increased resolution. One example is nonlinear processing that generates new musical information from the original signal - you can of course just reduce the gain after processing, but you are then sacrificing some of the resolution of the new combined signal, which itself could otherwise be used by further downstream processes. This all happens post-recording, but can still be musically important before getting to the finished product.

This is why DAWs work in 32-bit or 64-bit processing internally, and why many high-quality sample libraries will come in 32-bit, especially smaller one-shots. I often convert samples to .flac for space reasons, and have to either skip 32-bit .wavs or downsample them to 24.

Re: FLAC 1.4.0 released – added support for 32-bit audio

#33

Post by thrdbndndn »

I personally can't care less about 32-bit, but unfortunately a few digital music stores I buy from use this format (delivered in WAV). And I don't want to downscale them simply for archival reasons.

Now I can at least re-compress them losslessly in FLAC. (previously I have to use Wavpack, which isn't bad but I'd prefer to have a single format in my media library.)

Re: FLAC 1.4.0 released – added support for 32-bit audio

#34

Post by klodolph »

simcop2387 wrote: post #29
klodolph wrote: post #20

Earlier quoted context omitted.

It is extremely hard to justify 32-bit audio from a technical standpoint, since it requires that every component in your audio chain has better than 144 dB dynamic range. In practice, just about none of the analog components in your audio chain will have that kind of dynamic range, and any analog components in the recording chain are unlikely to have that range either. The kind of equipment I'd expect to see in order…

I could see it as part of a pipeline/workflow where having that dynamic range lets you not worry about losing meaningful information through everything, even if you're going to compress it and take it back to 16bit cd quality at the end. Being able to losslessly store the results of each step in a FLAC file should be better than raw data since it'll be compressed and easier to manage then. That said, at the edges of…

> That said, at the edges of that I totally agree even 24-bit can be questionable there since a lot of the analog side doesn't have a noise floor that would let it be meaningfully used.

It's not that hard to beat 16-bit, which is 96 dB, using easy-to-find, off-the-shelf equipment. One example scenario is that you are recording something but you don't have a precise idea of how loud it will be ahead of time, so you record at low levels and rely on 24-bit capture to give you headroom above and noise floor below. Trying to capture at 16-bit can, in practice, be annoying and difficult because it is more likely that you will ruin takes by setting the gain wrong.

Re: FLAC 1.4.0 released – added support for 32-bit audio

#35

Post by dsr_ »

klodolph wrote: post #20
Night_Thastus wrote: post #10

I had no idea FLAC didn't store 32-bit. I'll need to look over my library and make sure nothing strange is going on. I'm curious if sites like Qobuz will suddenly replace some of their existing files with higher-bit copies if they already had them and just had no way to encode them as FLAC.

It is extremely hard to justify 32-bit audio from a technical standpoint, since it requires that every component in your audio chain has better than 144 dB dynamic range. In practice, just about none of the analog components in your audio chain will have that kind of dynamic range, and any analog components in the recording chain are unlikely to have that range either. The kind of equipment I'd expect to see in order…

Note that 144dB range is what you get from 24 bits per sample. 32 bits gets you another 48dB more.

Some of your ADC/DAC chain can reasonably claim 125dB range. Some amplifiers can claim 17 or even 18 bits above their noise floor - 108dB.

No full-spectrum microphones, headphones or speakers can reasonably claim 125dB without distortion, but if they did you would still want to limit your exposure to "never". Long-term damage begins with long-term exposure under 96dB.

Re: FLAC 1.4.0 released – added support for 32-bit audio

#36

Post by jrajav »

squeaky-clean wrote: post #27
colejohnson66 wrote: post #6

Earlier quoted context omitted.

You're correct; lossless formats aren't needed by the average consumer. But the problem they solve is a very real thing. Think of the difference between a repeatedly edited JPG vs. a repeatedly edited PNG. Every save of the JPG destroys information irretrievably, whereas every save of the PNG keeps it all. It's the same with MP3 vs. FLAC: MP3 throws away information each export, but FLAC doesn't. For an example, musi…

(I think) They're not saying FLAC is pointless, just that 32 bit audio is. Even music producers record and export at 24bit, 32/64bit is only used for the effects and mixing (because compounding quantization noise and rounding errors is very real). You can't find 32 bit PCM music anywhere, even hifi DVD audio is 24bit/96khz.

We don't always record and export at 24-bit, though that's always the end result from mastering (if not 16-bit). In some contexts, 32-bit files are common for samples and for transferring in-progress artifacts like mixed tracks that are ready for mastering.

Re: FLAC 1.4.0 released – added support for 32-bit audio

#37

Post by hunter2_ »

simcop2387 wrote: post #29
klodolph wrote: post #20

Earlier quoted context omitted.

It is extremely hard to justify 32-bit audio from a technical standpoint, since it requires that every component in your audio chain has better than 144 dB dynamic range. In practice, just about none of the analog components in your audio chain will have that kind of dynamic range, and any analog components in the recording chain are unlikely to have that range either. The kind of equipment I'd expect to see in order…

I could see it as part of a pipeline/workflow where having that dynamic range lets you not worry about losing meaningful information through everything, even if you're going to compress it and take it back to 16bit cd quality at the end. Being able to losslessly store the results of each step in a FLAC file should be better than raw data since it'll be compressed and easier to manage then. That said, at the edges of…

The 55% compression ratio (or whatever the case may be) seems much more useful at the end (where it nearly doubles how long a consumer can listen before swapping media) then along the way (where it nearly doubles how much raw material a studio can capture before swapping media).

Re: FLAC 1.4.0 released – added support for 32-bit audio

#38

Post by jrajav »

squeaky-clean wrote: post #31
atoav wrote: post #5

Earlier quoted context omitted.

I am a recording engineer and I will choose 32 bits over 24 any day when recording. Of course you need the right (exceptionally good!) preamps to even make a difference here, but when you are manipulating audio 32 bits and upwards (for summing) are the default (for a reason). Having something to store those files with a little bit of lossless compression is a welcome addition

It's very unlikely your audio interface can actually record at 32 bit resolution. https://www.mojo-audio.com/blog/the-24bit-delusion/ 32bit or more makes sense for dsp and summing, and non-musical data storage. But your I/O is most likely not giving 32 bits

32-bit is common in field recordings, like with a Zoom (and there's reason to believe they can legitimately take advantage of it).

Re: FLAC 1.4.0 released – added support for 32-bit audio

#39

Post by klodolph »

jrajav wrote: post #32
klodolph wrote: post #20

Earlier quoted context omitted.

It is extremely hard to justify 32-bit audio from a technical standpoint, since it requires that every component in your audio chain has better than 144 dB dynamic range. In practice, just about none of the analog components in your audio chain will have that kind of dynamic range, and any analog components in the recording chain are unlikely to have that range either. The kind of equipment I'd expect to see in order…

You're absolutely right insofar as you're speaking about static audio that's already been produced and finished - there is almost no point in storing anything above 24-bit integer as far as dynamic range even for archival purposes. However, there is a legitimate purpose behind having higher dynamic range for production purposes and sample sources. There are some recording sources that can actually produce 32-bit audi…

> However, there is a legitimate purpose behind having higher dynamic range for production purposes and sample sources.

This is the justification for 24-bit audio... is there a reason why 24 bits is not enough here?

If you're capturing audio sources directly, you'd use something like a 24-bit ADC, which you can find easily enough. The "raw" output of the ADC is 24 bits.

If you're doing intermediate processing in your DAW, then the DAW is using single-precision floats (or possibly double), which cannot be losslessly converted either to 32 bit or 24 bit integers, so how would you choose the right format to store? It seems to me that you'd either store the original floating-point data, or you'd perform some kind of lossy conversion to a high-quality archival format... but if you do that, isn't 24 bits good enough? You're quantizing either way, and at 24 bits, you can have plenty of headroom and noise floor at the same time. Loads, even.

Re: FLAC 1.4.0 released – added support for 32-bit audio

#40

Post by jrmcauliffe »

colejohnson66 wrote: post #23
Night_Thastus wrote: post #19

Earlier quoted context omitted.

Yes, you only need that many samples given you know a maximum frequency. But to actually perform the conversion from discrete samples to continuous wave takes infinitely many steps. The number a given DAC actually does varies. Some do hundreds, some thousands, a couple rare (very expensive) ones do 100k or more. That's what I'm saying. Increase the number of samples in the audio itself, and the DAC can get closer to…

Except it's not. The video shows that. In the real world, the DAC doesn't immediately jump from code N to N+1; it slides (the "slew rate" of the opamp). More bits just makes the difference between codes N and N+1 smaller; i.e. where it slides to is more accurate to the original. The "stair step" or "straight line" view you get from programs like Audacity is a lie.

A final low pass filter (tuned to remove anything above half the sample rate) allows the accurate reconstruction of the original analogue waveform from the sampled digital data. ( The vertical 'stair step' of sampled data is very high frequency information which gets removed, 'bending' the output back into it's original shape). The video linked above is well worth a watch.
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