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Topic: Can lossy high resolution outperform lossless at standard resolution? (Read 2452 times) previous topic - next topic
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Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #25 –
Quote from: AhoyMatey on
Maybe if people had their ears bleed more often with such high-pitched tones, they would think twice about advertising it as a positive thing.

Personally, I focus on hunting for the mastering that makes me happier, stimulating by day or soothing by night, rather than salivating at the sight of ever-increasing numbers. Sometimes songs are remastered for the hi-res edition, so they may have, to the delight of fans, more nuances that were previously sacrificed in the loudness war. However, the pleasantness of such mastering is hardly related to its sampling rate and bit depth — the role of these numbers increases during editing and decreases during playback. So if the mastering turns out to be bloated to give solidity to weightless files (e.g. 24/192), it makes sense to bring it down to the classic audio standard that has been proven to be sufficient, at least for the sake of a more economical and eco-friendly use of resources. Further improvement exploration of how your favorite songs might sound different requires more or less esoteric devices, purchased or self-assembled: R2R DAC, tube amplifier and planar headphones to name a few. But, in the grand scheme of things, all we need is love to be grateful for the fact that we have hearing at all and improve it first to notice quiet facts against the backdrop of alluring manipulations, to enjoy the silence, and to feel the echoes of celestial music in the anxious-free simplicity.

• Join our efforts to make Helix MP3 encoder great again
• Opus complexity & qAAC dependence on Apple is an aberration from Vorbis & Musepack breakthroughs
• Let's pray that D. Bryant improve WavPack hybrid, C. Helmrich update FSLAC, M. van Beurden teach FLAC to handle non-audio data

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #26 –
Quote from: .halverhahn on
Foobar 2000 and the mda dither DSP component for foobar2000 is quite handy to do the job.
It will reduce bitdepth to e.g. 20bit, apply noise shaped dither and save it into a 24bit FLAC (lower bits are empty).
No science but a few samples using 18bit shaped dither with this plugin additional to lowpassing at 25kHz, 24dB/octave inside a 24/96 file suggests flac bitrates around 1500kbps.
The shape may be a bit stronger and the filter more refined to optimize it.
I didn't find an easy way to automate it. I am no expert for foobar.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #27 –
Quote from: guruboolez on

@shadowking > thanks for your advice. Your long experience with WavPack lossy is very useful and to be fair I was waiting for your contribution :) But -b6 seems really high. I was expecting WavPack lossy to be more efficient with HR files (more room to handle noise). Am I wrong?

You may be correct . I read the manual again and bryant quotes 1024k is enough to store all the bandwidth for 24/96.
So, If 192/24 source uses similar bandwidth as 96/24  then 1024kbps may be enough . 

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #28 –
Quote from: shadowking on
You may be correct . I read the manual again and bryant quotes 1024k is enough to store all the bandwidth for 24/96.
So, If 192/24 source uses similar bandwidth as 96/24  then 1024kbps may be enough .
Fine, thanks!

Quote from: Wombat on
I didn't find an easy way to automate it. I am no expert for foobar.
That's a big issue for me  :o
I tried a different way: instead of lowpassing HF to ~26 KHz and encode to 96000 Hz, I tried to to convert to FLAC using an odd sampling rate (which is supported according to FLAC documentation).
I tried first with FLAC at 54000 Hz:
  • 18 bit / 54000 Hz = 848 kbps on average
  • 19 bit / 54000 Hz = 1002 kbps on average
  • 20 bit / 54000 Hz = 1108 kbps on average
It works well. I don't know if all players are compatible with such odd sampling rate.
I tried then 60000 Hz, 58000 Hz, 56000 Hz, 52000 Hz => output file is always 192.000 Khz. Is it a bug or a feature? Probably a bug. I'm able to create a 60000Hz and to save it at the same sample rate with my old Audition and Plug-in (FLAC1.21).

If I limit the sampling rate to 48000 Hz:
  • 20 bit / 48000 Hz = 1011 kbps
  • 19 bit / 48000 Hz = 947 kbps
  • 18 bit / 48000 Hz = 823 kbps
  • 17 bit / 48000 Hz = 733 kbps
  • 16 bit / 48000 Hz = 648 kbps
  • 16 bit / 48000 Hz basic (no DSP used, only truncation through foobar's FLAC "highest bps supported = 16" in converter) : 601 kbps

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #29 –
If I summarize:

  • Using Vorbis at 500 kbps and 192.000 Hz is probably not a good thing
  • Keeping 192.000 Hz is a total waste of space: no information but noise on all recordings I tried (and most of them are modern and state-of-the-art recordings from the last three years
  • 96.000 Hz is from an perceptual point of view the same waste, but from a technical point of view the upper frequencies contains real information (but of course not audible)
  • At the moment I wasn't able to create a TransPCM file (I quickly gave up I admit, it's low on my priority list
  • At the moment I have some issues with HR files and LossyFLAC: Nick is checking
  • I was able to gather some bitrate data for FSLAC, WavPack Lossy and resampled/dithered FLAC
An excel file is available at the bottom.

At the moment, the possible formats of choice are:
  • FSLAC: FSLAC -2 is probably a bit low on quality but bitrate = 640 kbps at 96.000 Hz! ; FSLAC -3 = 1200 kbps at 96.000. Not a real competitor (not tuned for 24 bit) but for curiosity only.
  • WavPack lossy -4: 800 kbps at 96.000 Hz. Not too far from my classical Red Book bitrate. Very minor risk of artifact/noise
  • WavPack lossy -3: 590 kbps, which is exactly my usual bitrate for classical Red Book 16/44100. But how often is it not transparent?
  • FLAC: resampled to 48000 and 20 bit = 1000 kbps. Not bad. A few improvements over Red Book (+4000 Hz, +4bit) and decent bitrate. No fear of artifact or noise
  • FLAC: resampled to 54000 and 19 bit = 1000 kbps. Not bad either (+10.000Hz and +3bit over RedBook).
  • FLAC: resampled to 54000 and 18 bit = 900 kbps. (+10.000Hz and +2bit over RedBook).

An interesting start would be to check (if possible) if FLAC 16/44100 is better than WAVPACK LOSSY at 96.000 Hz (b3 setting). Both have a very similar bitrate for classical music at least.
Another choice would be to choose something in the ~1000 kbps, between pure FLAC at odd sampling rate and bitdepth and WavPack, and probably LossyFLAC at similar bitrate.

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #30 –
Are you confident then that the resampling doesn't make for clipping?
A volume adjustment of -3 dB would safeguard (maybe completely?) - and also it does away with half a bit. Since you are considering 18, 19 and 20 - there is nothing "wrong" about going in between?

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #31 –
@Porcus: you're right, I haven't thought about clipping!

EDIT: lowering the volume also reduces the bitrate: from 1011 kbps to 964 kbps with FLAC 1.42 -8, 48.000 Hz and 20 bit. It's -1 GB on my setlist (19.9 Gb to 18.9 Gb). I'll probably correct the table in the next days.

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #32 –
Hi Guru!  :)

I’ve over the years sort of given up on this topic because there seems to be a very limited audience for any middle ground here. I looked back and 16 years ago I made comments here and displayed graphs (which are now gone, along with most of my text) and got virtually no response. I’m responding to your question now, but also trying to give a more general answer summarizing my thoughts regarding WavPack lossy as a high-resolution storage or distribution format. And the other options you are considering are also basically similar and perfectly viable, if perhaps not as straightforward.

What to do with huge high-resolution downloads?

If you’re an objectivist then the obvious choice is to transcode everything high-res to 16/44.1 or 16/48 and be done with it because you can’t ABX it and there’s no definitive evidence that anything else sounds any better. AAC or Opus might be better still.

On the other hand, if you’re a subjectivist then any form of lossy encoding is very suspect (and virtually always audible), so lossless is the only way forward. Uncompressed might be better still.

Neither of these philosophical camps have ever left any space for something like lossy WavPack. Depending on your viewpoint it’s either “why bother?” or “why risk it?”

Let’s assume for a moment that the people who regularly report the improvements in high-resolution audio actually do experience something. I mean, the hard evidence is overwhelmingly against it, but let’s pretend there’s something there that we don’t want to miss out on, especially after we paid extra for the hi-res version (even if it’s because we’re paranoid that they intentionally make the lower-res versions sound worse). What could it be? Well, there are only three possibilities (and perhaps some combination):

  • The dynamic range resulting from the 24 bit depth is important.
  • The bandwidth from the higher sampling rate is important.
  • The signal-to-noise ratio from the 24 bit depth is important.

Obviously #1 and #3 are related, but I listed signal-to-noise ratio last because I believe it’s the least likely to be significant. The reason we go to 24-bit is not because we need the noise floor to be 144 dB below the music at full scale (which is just silly), but because when the signal level is much lower, we don't want to run into the noise floor. Turn the volume way up during a very quiet passage from a CD (like a reverb tail) and the hiss (or distortion, if not properly noise-shaped) you hear is the limitation of 16-bit audio.

Of course, don’t really do this because when the music starts again you’ll damage your ears or speakers, and it can be argued that this is somewhat irrelevant because it’s unlikely that a single volume setting will allow you to both tolerate the loud parts and hear the hiss in the quiet parts (unless, of course, the original material has a higher noise floor than CD quality, which means higher bit depth won’t buy much). But the point is that 24-bit audio has the advantage of a greater dynamic range than 16-bit, and this is achieved with a higher signal-to-noise ratio. But, that’s not the only way to increase the dynamic range, and in fact it’s a rather expensive way.

So, if we can assume that only #1 and #2 are possibly significant, then something like WavPack lossy might provide the perfect solution. It’s all done in the time domain, so there’s no loss of bandwidth, and because the quantization error scales with the level, there’s no loss of dynamic range (at very low levels it reverts to lossless). The only thing lost is the ultimate signal-to-noise ratio, which I’ve argued above is not the actual purpose of using 24 bits.

In fact, I’ll argue that linear PCM is really extraordinarily wasteful. The number of bits being consumed to have 144 dB of signal-to-noise ratio at 48 kHz (or 96 kHz!) is crazy. Lossless compression works to get rid of the space above the signal, which is nice, but it’s the depths below the signal that are an even greater waste.

For real-world numbers, I regularly use -hx4b4 for lossy compression of 24/96 material. Generally this results in about 800 kbps, which is somewhere around 3.5 times less than what lossless compression would yield. Here’s a typical comparison of the signal and noise spectrum. Note that the signal and noise move up and down together, but at any time the noise is down (compared to the signal) around 20 dB at 20 kHz, and more like 60-70 dB in the midrange.



I also just tried using just 3 bits per sample for some 24/192 material I created from a DSD128 recording. You can see the source DSD noise staring up around 45 kHz and the new noise is just peeking out above that by about 6 dB (except at the highest frequencies), and in this case the final bitrate is almost 4.5 times less than lossless (1192 vs. 5328 kbps). I’m sorry, but that’s just a crazy waste.



Another aspect of this worth mentioning is that the noise component is generally inaudible in isolation when played at the same level as the signal. In other words this lossy encoding does not rely on masking like traditional codecs, and it makes sense (to me anyway) that if the noise is not audible without the music present (which is much easier to test) then it’s not going to suddenly become audible with the music added.

You can obviously create correction files if you’re not ready to delete the original, which will result in very little, if any, overhead compared to the original FLACs. Or increase the bits one or two to be conservative and just keep the lossy (the numbers I’m suggesting here are minimum recommendations).

To summarize, I’ve given up suggesting this as a viable alternative to conventional hi-res recordings, although maybe with people having second thoughts about MQA this will be revisited. The bottom line is if you’ve downloaded hi-res recordings it would be a little strange to simply down-convert them to 16/44.1 or 16/48, especially since those resolutions were probably also available at the time for less money. But I think I’ve demonstrated that for about the same bitrate, WavPack lossy allows you to retain the additional information rather than just discard it. Whether that additional information would actually be audible becomes somewhat irrelevant when the goal is just piece of mind.

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #33 –
Quote from: bryant on
Turn the volume way up during a very quiet passage from a CD (like a reverb tail) and the hiss (or distortion, if not properly noise-shaped) you hear is the limitation of 16-bit audio … the point is that 24-bit audio has the advantage of a greater dynamic range than 16-bit, and this is achieved with a higher signal-to-noise ratio.

The advantage comes while editing. As for playback, how many bits can you hear?

Quote from: bryant on
If you’re a subjectivist then any form of lossy encoding is very suspect (and virtually always audible)…

I remember subjectivists who, ignoring the research of optical illusions, saw signs of civilization in low-resolution spots on Mars that resemble a face. Okay, there is Pi. It is used, for example, to build bridges and dams. The decimal expansion of Pi is infinitely long, namely 3.1415926535897932384626433… Downsampling 192 kHz and higher rates at least by a factor of 4 is as lossy as rounding Pi up to this length, which is still sufficient to serve the purpose. Expecting someone to hear the difference is like expecting someone's eyes to see millions of bacteria, fungi and viruses that compose our skin microbiota. It's just that the word lossy, uttered without specifying the scale of the loss, first brings to mind the worst artifacts of the MP3 childhood, whereas in this case it's just the operation that was not done in the studio for marketing reasons, although those anxious folks somehow accept without worries the fact that the studio reduced 64-bit or 32-bit float to 24-bit integer before delivery. No doubt in the future they will worry about this too.

Quote from: bryant on
Neither of these philosophical camps have ever left any space for something like lossy WavPack.

I had. But then I found a few cases when WavPack hybrid failed. You called those cases anomalies. But in the course of your explanation, you outlined ways how this encoding mode can be improved, which is what I now pray for, even in my own signature. Until then, WavPack lossless only, which looks advantageous against FLAC, which has difficulties with the preservation of non-audio data. Peace of mind, you know.
• Join our efforts to make Helix MP3 encoder great again
• Opus complexity & qAAC dependence on Apple is an aberration from Vorbis & Musepack breakthroughs
• Let's pray that D. Bryant improve WavPack hybrid, C. Helmrich update FSLAC, M. van Beurden teach FLAC to handle non-audio data

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #34 –
Quote from: Kraeved on
Quote from: bryant on
Neither of these philosophical camps have ever left any space for something like lossy WavPack.

I had. But then I found a few cases when WavPack hybrid failed. You called those cases anomalies. But in the course of your explanation, you outlined ways how this encoding mode can be improved, which is what I now pray for, even in my own signature. Until then, WavPack lossless only, which looks advantageous against FLAC, which has difficulties with the preservation of non-audio data. Peace of mind, you know.
Yes, I believe that those samples are pathological anomalies. I am curious about them, and have always been interested in different noise-shaping techniques, but I am not working on that and have no immediate plans to. WavPack lossy is not intended to be transparent at any particular bitrate nor is it intended to be competitive with standard codecs at conventional sampling rates. The fact that a couple samples require a higher bitrate should not come as a huge surprise, especially considering WavPack’s relative simplicity. Also consider that neither sample came from CDs or even legitimate music downloads and that they also break many conventional codecs (which is in fact how the first was supposedly discovered). So to call these “failures” and disqualify the mode from contention seems a little odd to me, especially when you refuse to entertain the -h and higher -x modes. But of course this is your call to make.

The application being discussed in this thread is something that conventional lossy audio codecs do not pretend to handle and their authors might even consider pointless (i.e., human hearing extends to 20 kHz, so the first thing they do is remove everything above that). That said, a pathological sample could easily be produced here that also triggers the same “failures”, and I would produce such a sample myself except that in the wild it would pose a real danger to fragile audio systems (tweeters and amplifiers specifically) if played loudly enough. That’s not the point however, and I believe this could be extraordinarily reliable given the usual sources of high-resolution music, which tend to be primarily acoustic and carefully recorded.

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #35 –
I mentioned James D. (jj) Johnston suggests a FIR filter we may use as endgame lowpass. Isn't there a foobar plugin already that can handle directly such a formula?
Room correction comes me to mind here.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Re: Can lossy high resolution outperform lossless at standard resolution?

Reply #36 –
@bryant > many thanks for your detailed answer. Your feedback as developer is really precious  :)