HydrogenAudio

Lossless Audio Compression => FLAC => Topic started by: foorious on 2008-07-25 16:55:18

Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: foorious on 2008-07-25 16:55:18
Hi everybody,

I've just made a small comparison between Monkey's Audio 3.99 (Extra High Compression) and FLAC 1.21 (Compression level 8 ), using 24bit/192KHz/stereo files (the files were generated from a vinyl rip).

Of course I expected APE to perform slightly better than FLAC, like it usually does for 16bit/44KHz/stereo files (2-3%, maybe even 5%)... but I didn't really expect this ! 

[a href="http://img366.imageshack.us/my.php?image=californicationpq9.jpg" target="_blank"]
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: viniciusferrao on 2008-07-26 00:47:03
MonkeyAudio do not support 192kHz! :confused:

Moderation: Removed unnecessary quote.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: Axon on 2008-07-26 00:51:38
My understanding is that the lowest 8-12 bits of a 24-bit recording are pretty much white noise (as LossyWAV has so handily illustrated). Every lossless codec handles pure white noise equally bad, but they handle low-level white noise considerably differently. APE's encoding tends to do considerably better.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: Curtor on 2008-07-26 02:38:07
MonkeyAudio do not support 192kHz! :confused:

From the Monkey's Audio FAQ:

Exactly what kind of files does MAC support?
For now, the list goes like this: (but it'll hopefully grow as time goes on)
Format: PCM WAVE (standard windows .wav file)
Sample Rate: anything
Bit depth: 8 or 16 or 24
Channels: 1 or 2
As a note, MAC has been tuned primarily for 44khz, 16-bit stereo music, since this is what today's CDs are.

192kHz fits into the "anything" category.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-07-27 04:48:51
Take a look at all the file sizes : we're talking about 20% difference here ! The total file size is 1,53 Go for APE vs. 1,88 Go for FLAC.

Not really surprising for me...

From earlier evaluations of some 44 Khz files i knew, that FLAC has some weaknesses when it has to deal with low passed files. Well, because 192 Khz audio recordings usually don't contain much frequencies above 20 Khz, they could also be considered as low passed. Therefore i expected to see FLAC perform worse on 192 KHz samples.

Out of interest i unlocked TAK support for 192 KHz files (the last official release only supports up to 96 KHz). Since i don't have any 192 KHz recordings i upsampled the 13 files of my 24-bit/96 KHz test corpus (Cooledit with maximum quality settings).

Results:

Code: [Select]
FLAC 1.2.1
  -8               46.20
  
Monkey's Audio 3.99
  High             38.09
  Extra            35.52
  Insane           35.76

OptimFrog 4.600ex
  --ExtraNew       29.98

TAK 1.0.4 (with 192 Khz support unlocked )
  -p0              45.15
  -p1              37.93
  -p3m             34.91
  
TAK 2.0 (Developer version)
  -p3m             31.94
  
TTA 3.4
  Default          39.41
    
WavPack 4.41
  -hhx3            44.84
  -hhx4            34.01
  -hhx6            33.40

Quite similar to your findings...

So I don't understand. I'm a genuine FLAC enthusiast (all my files are FLAC), but... how can it be ? Is there something wrong here ? Can we do something to improve all the FLAC file sizes ?

I think the resolution/accuracy of FLAC's predictor coefficients isn't sufficient to deal with such files. I don't know, if it's possible to increase the accuracy without breaking the FLAC format.

  Thomas

edit: Results for Monkey's Audio added.
edit 2: Updated the results for TAK -p0 to -p2. Better compression because of a quick optimization of some parameter estimation in the encoder.
edit 3: Results for WavPack -hhx3 added.
edit 4: Results for WavPack -hhx4 and -hhx6 added.
edit 5: Results for TAK 2.0 (Alpha, unreleased!) added.
edit 6: Results for TTA added.
edit 7: Results for OptimFrog added. Results for TAK 2.0 updated.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: foorious on 2008-07-27 16:38:59
Thanks everyone for all your interesting answers.

Well, so it looks that FLAC isn't really well-suited at the moment for low-passed files, thus for 96 and 192 KHz files. Considering the results, I think it will be better for me to stick with FLAC for 16/44 files, but to switch to another format for 24/96 and 24/192 files. I don't like the idea of handling two different lossless formats in my collection, but the gap is huge, and I don't see any reason for losing almost 350 MB of disk space for a single album.

I secretly hope Josh Coalson has some ideas in store for improving FLAC's handling of HD audio files. We'll see !

Oh, one last question : in your opinion, is this issue related only to the frequency (96, 192 KHz) or also to the bits per sample ? In other words, would FLAC perform much better with 24bit/48KHz files than it does with 24bit/192KHz files ?
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: Nick.C on 2008-07-27 17:22:23
My understanding is that the lowest 8-12 bits of a 24-bit recording are pretty much white noise (as LossyWAV has so handily illustrated). Every lossless codec handles pure white noise equally bad, but they handle low-level white noise considerably differently. APE's encoding tends to do considerably better.
Using two of the freely available Nine Inch Nails - The Slip downloads, 16/44.1 and 24/96, it is interesting to note the following:

24/96 lossless (FLAC -5) : 2954 kbit/s (926MiB); lossyWAV --standard|FLAC -5: 787 kbit/s (247MiB)
16/44.1 lossless (FLAC -5) : 637 kbit/s (200MiB); lossyWAV --standard|FLAC -5: 476 kbit/s (149MiB)
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: Dynamic on 2008-07-27 18:36:13
Oh, one last question : in your opinion, is this issue related only to the frequency (96, 192 KHz) or also to the bits per sample ? In other words, would FLAC perform much better with 24bit/48KHz files than it does with 24bit/192KHz files ?


In conjunction with NickC's results, perhaps resampling (fb2k/Resampler) to 44.1 kHz and/or 48 kHz in the Convert DSP while retaining 24-bit output would answer that, and offer comparison between 16/44.1 and 24/44.1 when processed through lossyWAV (though it isn't certain the 16/44.1 is the same as a straight downconversion from the 24/96 files)
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-07-27 18:53:53
Oh, one last question : in your opinion, is this issue related only to the frequency (96, 192 KHz) or also to the bits per sample ? In other words, would FLAC perform much better with 24bit/48KHz files than it does with 24bit/192KHz files ?

Yes, it does. The problem with the limted predictor coefficients accuracy is rarely an issue up to 96 KHz.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: Nick.C on 2008-07-27 20:30:55
In conjunction with NickC's results, perhaps resampling (fb2k/Resampler) to 44.1 kHz and/or 48 kHz in the Convert DSP while retaining 24-bit output would answer that, and offer comparison between 16/44.1 and 24/44.1 when processed through lossyWAV (though it isn't certain the 16/44.1 is the same as a straight downconversion from the 24/96 files)
Taking onboard your comment regarding whether the 16/44.1 is a straight downconversion of the 24/96, I used the SSRC dsp plugin (ultra mode) in foobar2000 to resample the 24/96 version down to 48kHz and 44.1kHz and got the following:

24/96 lossless FLAC -5: 2954 kbit/s (926MiB); lossyWAV --standard|FLAC -5: 787 kbit/s (246MiB);
24/48 lossless FLAC -5: 1598 kbit/s (501MiB); lossyWAV --standard|FLAC -5: 517 kbit/s (162MiB);
24/44.1 lossless FLAC -5: 1489 kbit/s (466MiB); lossyWAV --standard|FLAC -5: 498 kbit/s (156MiB);

Also, I changed the bitdepth in foobar2000 and dithered the 24/96 version to 16/96 and got:

16/96 lossless FLAC -5: 1421 kbit/s (445MiB); lossyWAV --standard|FLAC -5: 776 kbit/s (243MiB);
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: GeSomeone on 2008-07-28 09:17:33
24/44.1 lossless FLAC -5: 1489 kbit/s (466MiB); lossyWAV --standard|FLAC -5: 498 kbit/s (156MiB);

16/96 lossless FLAC -5: 1421 kbit/s (445MiB); lossyWAV --standard|FLAC -5: 776 kbit/s (243MiB);

Seems to me that FLAC has a "weakness" with compressing 24bit files (though I never have bothered with 192kHz).  If you're looking for another codec (besides the mentioned Monkey or TAK), wavPack does better with 24bit files than FLAC too.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: DARcode on 2008-07-28 11:42:10
24/44.1 lossless FLAC -5: 1489 kbit/s (466MiB); lossyWAV --standard|FLAC -5: 498 kbit/s (156MiB);

16/96 lossless FLAC -5: 1421 kbit/s (445MiB); lossyWAV --standard|FLAC -5: 776 kbit/s (243MiB);

Seems to me that FLAC has a "weakness" with compressing 24bit files (though I never have bothered with 192kHz).  If you're looking for another codec (besides the mentioned Monkey or TAK), wavPack does better with 24bit files then FLAC too.
Yup, from the features listed on the WavPack main page (http://www.wavpack.com/):
Quote
  • Compatible with virtually all PCM audio formats including 8, 16, 24, and 32-bit ints; 32-bit floats; mono, stereo, and multichannel; sampling rates from 6 to 192 kHz (and non-standard rates)
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: pawelq on 2008-07-28 15:25:37
From the Monkey's Audio FAQ:


Sample Rate: anything


This must be a lie. You can't have "anything" in a digital computer with finite memory.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: Enig123 on 2008-07-28 15:34:35
I think "anything" here just means no particular restrictions.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: pdq on 2008-07-28 16:23:13
If you treat the data as simply a series of values and compress them accordingly then it makes no difference at what sample rate you play them back. It only matters that the desired platback sample rate can be expressed to the playing device. I assume the limitation here is how this value is encoded in a WAV file.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-07-28 18:04:03
If you're looking for another codec (besides the mentioned Monkey or TAK), wavPack does better with 24bit files then FLAC too.

Well, i have added the result for WavPack -hhx3 to my comparison above. It too seems to be less efficient with 192 KHz/ 24 Bit, only slightly better than FLAC. At least with my sample set.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: SebastianG on 2008-07-28 18:36:54
This is in response to the original question.

FLAC's problem (not the format's but the current reference encoder's problem) might be the suboptimal quantization of LP coefficients. In case of such high sampling rates and signals where there's almost nothing above 20 kHz the optimal LP filter's magnitude response is pretty far from being flat which implies that simple per-sample quantization of the LP coefficients may lead to large spectral distortions (= large discrepancy between calculated and quantized filter).

Whether choosing a better quantization method really makes a big difference needs to be tested. If anyone is willing to try here's what needs to be done:'x' will contain the quantized LP coefficients. Merging quantization with the last "triangular solver" will reduce the spectral distortions. To go one step further (optimal set of quantized coefficients for a given filter order and 'scale' value) find 'x' with integer coefficients that minimizes ||1/scale*L^T*x-b||. This is not trivial but possible (lattice vector quantization). How quantization is done currently in FLAC is equivalent to the partition 'C' in the following picture. The one I described is equivalent to partition 'B' and partition 'A' is the one that leads to the optimal solution -- the more sphere-like the better.
(http://img378.imageshack.us/img378/2553/lvqqb7.th.png) (http://img378.imageshack.us/my.php?image=lvqqb7.png)
(image taken from this paper (http://www.eng.tau.ac.il/~zamir/papers/lqn.pdf), the hexagonal lattice is just an example for the lattice defined by the matrix L.)

Also, it might be a good idea to check whether the current heuristic for choosing the LP coefficient accuracy (scale) could be improved for the case "24 bit + high sampling rate". In this regard I'd like to mention that the Levinson-Durbin algorithm has the advantage that it estimates the sum of squared prediction errors. LP coefficient quantization simply adds ||1/scale*L^T*x-b||^2 to this estimate which could help choosing the right scale factor for the LP coefficients.

Cheers,
SG

edit: fixed bug in above paragraphs (I mixed up L and L^T)
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: Dynamic on 2008-07-28 19:46:34
Seems to me that FLAC has a "weakness" with compressing 24bit files (though I never have bothered with 192kHz).  If you're looking for another codec (besides the mentioned Monkey or TAK), wavPack does better with 24bit files then FLAC too.


I happened to have conducted some tests yesterday, as yet unpublished, with reference to lossyWAV and clipping. Here's a preview of some tests of a fairly loudly mastered 2005 album, Keane's Hopes And Fears (Album Gain -9.87 dB) with all metadata stripped away (encoded with wavpack -hm or the recommended -hm --block-size 512 --merge-blocks in the case of lossyWAV processed files)

Duration: 50:37.120 (133936992 samples)

Filesize    Filename
361,738,994 16bitlossless.wv (952kbps)
361,756,956 24bitpadded.wv (952kbps)

which shows Wavpack handles the same 16-bit data marginally better when padded with zeroes to 24-bit, surprisingly, but essentially the same overall bitrate.

180,156,448 16bitStd.lossy.wv (474kbps)
179,583,978 24bitStd.lossy.wv (473kbps)
179,472,308 24bitStdScale0.5.lossy.wv (472kbps)

This shows the same with lossyWAV -standard processing, and the --scale 0.5 version eliminates any potential clipping without losing any original data (because when scaled it originally occupied only bits 7 to 22, with bit 23 as headroom), thus allowing lossyWAV to reduce bit-depth unimpeded by clipping prevention.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: bryant on 2008-07-29 17:17:59

If you're looking for another codec (besides the mentioned Monkey or TAK), wavPack does better with 24bit files then FLAC too.

Well, i have added the result for WavPack -hhx3 to my comparison above. It too seems to be less efficient with 192 KHz/ 24 Bit, only slightly better than FLAC. At least with my sample set.

Thanks for trying out WavPack! Since we're talking about non-standard files here, I think that -hhx4 (or higher) would be a much better choice (even though it's much slower). The -x values from 1-3 use pre-calculated filters while values from 4-6 generate custom filters.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-07-29 20:01:55
Thanks for trying out WavPack! Since we're talking about non-standard files here, I think that -hhx4 (or higher) would be a much better choice (even though it's much slower). The -x values from 1-3 use pre-calculated filters while values from 4-6 generate custom filters.

I have added the results for -hhx4 and -hhx6 to my comparison above. And the winner is... WavPack! 

Seems as if i have to tune TAK still a bit more for 192 Khz. 
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-07-29 21:49:36
Seems as if i have to tune TAK still a bit more for 192 Khz. 

Results for TAK 2.0 Alpha added to the comparison. 

It's far away from a release, but already performing quite well.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: bryant on 2008-07-30 05:33:06

Thanks for trying out WavPack! Since we're talking about non-standard files here, I think that -hhx4 (or higher) would be a much better choice (even though it's much slower). The -x values from 1-3 use pre-calculated filters while values from 4-6 generate custom filters.

I have added the results for -hhx4 and -hhx6 to my comparison above. And the winner is... WavPack! 

Seems as if i have to tune TAK still a bit more for 192 Khz. 

Wow! I expected an improvement, but I sure didn't expect over 10%!

So, for almost 2 hours WavPack beat TAK ... hehe, that's cool. 
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: vpa on 2008-07-30 18:39:15
Could you test TTA too?
It's very quick but gives usually better results than FLAC -8 (at least with 44.1 and 48 kHz material).
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-07-30 19:28:45
Could you test TTA too?
It's very quick but gives usually better results than FLAC -8 (at least with 44.1 and 48 kHz material).

Done.

But please, i don't want to make this look like an exhaustive or representative codec comparison. I would need more and especially real 192 KHz files for this purpose.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-07-31 13:01:37
So, for almost 2 hours WavPack beat TAK ... hehe, that's cool. 

 
And for almost one day TAK 2.0 was on the top: Optimfrog added to the comparison above.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: foorious on 2008-07-31 17:49:12
Just a simple question : do TAK, APE and Optimfrog support multichannel ?
I'm asking this because otherwise they would be quite useless for most 24/192 files  : the files for my initial example were stereo, but most 24bit files are also multichannel AFAIK (e.g. DVD-A)...

This reference wiki article says TAK, APE and Optimfrog do not support multichannel (maybe it needs to be updated ?), which would make WavPack the only serious alternative to FLAC for multichannel files : http://wiki.hydrogenaudio.org/index.php?ti...less_comparison (http://wiki.hydrogenaudio.org/index.php?title=Lossless_comparison)

BTW I'd really love if Josh Coalson would come across this thread. Hey, if TBeck has been able to fine-tune TAK and gain 10% in only a few hours time, maybe Josh could do something similar with FLAC ?

EDIT : PM sent to Josh to inform him about this topic.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: vpa on 2008-07-31 18:13:03
BTW I'd really love if Josh Coalson would come across this thread. Hey, if TBeck has been able to fine-tune TAK and gain 10% in only a few hours time, maybe Josh could do something similar with FLAC ?


Or Justin Ruggles. His Flake Encoder has usually a higher compression ratio at -99 compared to the FLAC reference encoder at -8.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: GeSomeone on 2008-08-11 22:56:49
I'm asking this because otherwise they would be quite useless for most 24/192 files  : the files for my initial example were stereo, but most 24bit files are also multichannel AFAIK (e.g. DVD-A)...
I'd like to make a correction here. On DVD-Audio only stereo tracks (groups) can be 24bit/192kHz, the max for multi channel is 24bit/96kHz but 24/48 is not uncommon.
The 192kHz sample rate is rather rare (on DVD-A) because it takes up a lot of space and often the (digital) sources were in a lower bit rate.

@TBeck, Bryant or whoelse needs 1 or 2 (classical) 192kHz files for a test, have a look on the Lyndberg Lyd (2L) HiRes Download - test bench (http://www.2l.no/hires/index.html) page.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: foorious on 2008-08-13 11:51:19
Yes GeSomeone, no problem, my question was only about TAK, APE and Optimfrog not supporting multichannel.

I hope this thread will remain alive until some answer comes also from the FLAC side (after all we are in the FLAC subforum aren't we ?). I'm surprised that Josh, Justin or another FLAC dev haven't replied yet... maybe they're on holiday, who knows ?
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: jcoalson on 2008-08-13 21:51:55
sorry, been traveling a lot lately... it's hard for me to tell what's going on with this particular sample without the sample, but I think sebastian probably has it right.  flac's current lpc coefficient precision may be sufficient with different/better lpc analysis.  or it's always possible to extend like the rice parameter was.

I have a big backlog of experiments to work on re: lpc analysis and they are low-priority because almost no one is using such high sample rates (probably because it's a pointless waste of space, I mean really where is 20-20khz  recording going to end, 1ghz?).  but if someone has time to try out sebastian's ideas I would be open to incorporating improvements into the encoder.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: foorious on 2008-08-13 23:53:57
Hi josh, thanks for joining in.

I understand your point, so I'd just like to emphasize on two things :

- The "problem" with FLAC doesn't seem to be dependant on a particular sample. On my initial example, all 15 tracks showed the 20% size difference with APE. Take a look at the picture.
- I agree with you, where is 20-20Khz recording going to end ? But the fact is in the forthcoming years we are going to see more and more 48 / 88 / 96 / 176 / 192 KHz music, in 24 or even 32 bits. Why ? Because the marketing guys have decided so : they want to replace all the CDs to sell more media (like BRDs are replacing DVDs), and there's not much we can do about it. I guess a major codec like FLAC can't go against the music market, even if it's not urgent yet.
- Besides, I also think a major codec like FLAC can't afford to be distanced (by 20%, not by 2-3%) by other wide-used codecs like APE when it could probably perform as well with some (minor I hope) tweaking.

If someone has the ability to work with Josh on this one by trying out Sebastian's ideas, that would be great for FLAC's future. Thanks !
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: SebastianG on 2008-08-14 09:24:29
I actually tested some LP coefficient quantization schemes. There's another popular algorithm that's used for preconditioning the ILS (=integer least squares) problem called LLL (http://en.wikipedia.org/wiki/Lenstra%E2%80%93Lenstra%E2%80%93Lov%C3%A1sz_lattice_basis_reduction_algorithm). So far I've only found a buggy Matlab implementation of this algorithm that's sometimes stuck in an infinite loop. But it usually gave even better coefficients compared to what I suggested earlier. Though, I'm not sure whether using the LLL algorithm for FLAC is really worth the hassle. Still, this lattice quantization problem is kind of intriguing. I'm going to check out the other LLL implementations that are mentioned by the wikipedia article ...

Cheers,
SG
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-08-14 12:44:58
@TBeck, Bryant or whoelse needs 1 or 2 (classical) 192kHz files for a test, have a look on the Lyndberg Lyd (2L) HiRes Download - test bench (http://www.2l.no/hires/index.html) page.

Thank you!

Especially the multi channel files will be useful for me.

Unfortunately the 192 KHz files are bad examples... I've performed a frequency analysis with cooledit and it looks quite strange: Above about 48 KHz there seems to be a lot of noise. Possibly this is due to the noise shaping mentioned at the bottom of the download page: "DSD signals further require a noise shaping process to sustain the dynamic range of 120 dB within the primary bandwidth of 20 Hz - 20 kHz but that causes the noise spectrum to increase above 22 kHz." But i am not an expert in this area.

I am sure those files will be very FLAC-friendly: Because of the high pitched noise they will not show it's inefficiency when dealing with low passed alike files.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-08-14 18:54:23
I am sure those files will be very FLAC-friendly: Because of the high pitched noise they will not show it's inefficiency when dealing with low passed alike files.

I've got time to test it:

Code: [Select]
FLAC 1.2.1
  -8               54.65
  
Monkey's Audio 3.99
  Extra            53.34
  
TAK 2.0 (Developer version)
  -p3m             53.51

Exactly what i expected.

But what are such 192 KHz files good for? Twice the space requirements than 96 KHz recordings only to add noise above 48 KHz? 
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: GeSomeone on 2008-08-15 13:19:25
But what are such 192 KHz files good for? Twice the space requirements than 96 KHz recordings only to add noise above 48 KHz? 
I forgot that L2 likes to record in (what they call) DXD, which is like DSD but twice the sample four times the data rate of DSD.
As I said I didn't bother with the 192kHz but the 96kHz 5.1 at least sounded pretty good.

BTW could there be a -A  function that could improve compression of 192kHz files?
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: TBeck on 2008-08-15 15:19:43
But what are such 192 KHz files good for? Twice the space requirements than 96 KHz recordings only to add noise above 48 KHz? 
I forgot that L2 likes to record in (what they call) DXD, which is like DSD but twice the sample rate.
As I said I didn't bother with the 192kHz but the 96kHz 5.1 at least sounded pretty good.

Thanks for the info!

The 96 KHz files don't show any abnormalities in my evaluations.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: SebastianG on 2008-08-16 11:12:05
"[...] but if someone has time to try out sebastian's ideas I would be open to incorporating improvements into the encoder."

"[...] Still, this lattice quantization problem is kind of intriguing. [...]"


Just in case anyone works on this: I sent Josh and Justin some C89 source code. It's able to compute approximations and the actual optimal set of quantized LP coefficients given a desired filter order and LP coefficient accuracy.

edit: Since Josh and Justin might not have enough time at their hands to incorporate this in its current form I'm willing to share the source code with others, too (simplified BSD license).

Cheers,
SG
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: foorious on 2008-09-17 22:58:56
Are there any upcoming developments on this matter from the FLAC side ? Thanks.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: hidn on 2008-09-24 05:58:47
i encode my cd. flac compression is close to another codecs, but have greatly fast decoding speed. so flac is my choice.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: jcoalson on 2008-09-24 06:33:20
Are there any upcoming developments on this matter from the FLAC side ? Thanks.

no, I don't really have the time lately for anything less than a drop-in replacement to libFLAC and even that would require tons of testing.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: foorious on 2008-09-26 00:55:18
Thanks Josh. I just hope you'll keep an eye on this issue for a future FLAC release. Let it be a (small) part of your 'to do list' for the future. Thank you.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: foorious on 2009-03-24 23:34:53
Hi there, are there any news on this matter ? It's been a long time, and it would be great if the next FLAC version could come with some enhancements for those 24 bit / 48-88-96-176-192 KHz files.

Josh, please don't forget this. Thank you.
Title: Comparison : 24bit/192KHz/stereo FLAC vs. APE
Post by: ktf on 2009-05-19 18:36:46
I just noticed the last SVN Flake is on par with Monkey's Audio

I downloaded FL Studio (again) on Windows just to play around with it, and generated a 192kHz/24-bit file from one of the demo's (SolidInc - What I Found) which has quite some content at around 80.000Hz. FLAC is on par with Monkey's there. When I lowpass it at 20.000Hz and keep it in the 192kHz/24-bit and encode it with Flake it even outperforms Monkey's.

Code: [Select]
Original, not lowpassed audio file
Wave: 296,5MB, duration 4:29
FLAC -8: 57,2%, took 43 sec (encoding CPU)
Flake -8: 54,4%, took 28 sec
Monkey's -c3000: 53,4%, took 38 sec
Wavpack -hh -x4: 53,6%, took 856 sec

lowpassed
FLAC -8: 53,9%, took 41 sec
Flake -8: 44,1%, took 29 sec
Monkey's -c3000: 44,7%, took 37 sec
Wavpack -hh -x3: 50,2%, took 187 sec
Wavpack -hh -x4: 27,0%, took 842 sec


Of course this isn't an in-depth analysis, but it shows that it is indeed a problem with the reference encoder, not with the FLAC format. As you can see, Wavpack's custom filters compress surprisingly better.