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Is FLAC really lossless? / Do compression settings make a difference?

Reply #25
Some people don’t want, or care, to use a non-default setting to gain what might be a negligible saving of space but also a sizeable increase in the processing power and time required. It’s a game of juggling numbers.

Have a look at the tests others have previously done, or—better—test a few files for yourself, assessing whether the additional time is worth the reduction in space.

It’s no more complex than that, certainly not a case of there being some shady reason for the choice. (Analogy: the option to read audio CDs at different speeds was recently invoked by a woo-wizard as evidence of this having some bearing on quality [in non-exceptional cases].)

Is FLAC really lossless? / Do compression settings make a difference?

Reply #26
Is xact a comparable program? im downloading that right now.


XLD is a CD ripper, AFAIK the only one on Mac that uses AccurateRip verify, and a format transcoder.
xACT is a collection of utilities, a sort of Swiss Army knife to manage audio files, maybe in a less straightforward way.
They both support some batch operations.
They both use internally the same Core Audio routines (for AAC, ALAC, AIFF etc...), FLAC reference distribution, Lame mp3 etc… so when doing the same operations their results are exactly the same. (edit: except ripping, for the reason above).

To use one or the other depends actually on your needs.
... I live by long distance.

Is FLAC really lossless? / Do compression settings make a difference?

Reply #27
i appreciate all the help. I've learned a lot from this thread.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #28
Okay, I just had to create an account in case someone like me wants to find out if FLAC is truly lossless and ends up in this crazy thread. None of the commands recommended to the OP have any relevance to whether or not the FLAC files are going to have the same quality as the original .wav or .aif files. They will merely show whether or not the different compression settings for the FLAC files contain the same amount of information when output.

To find out if your original files and FLAC files are identical in quality (which they should always be), all you have to do is  import the two files on separate tracks in any DAW (even Audacity, which is free),, and invert the phase on one. When you play the play the file, you should hear absolutely nothing. This is the only sure fire way to be positive you are getting exactly the same thing with the FLAC file as you are the .wav or .aif files. Phase inversion will cancel the audio signal out completely. This is how noise cancellation headphones work. If you've placed both files at the exact beginning of the project, leave all the volume and panning controls alone, and do nothing but invert one file, silence will tell you that you've got a perfect copy of your original. Anything you hear is different in one file or the other.

Just be careful if you use Audacity not to do anything with your original files. Changes you make with it are permanent. It's a destructive editor, meaning that it actually applies the changes you make in the program to the file you placed in it.

MODERATION

Recommendation removed, per TOS #14.  I recommend you figure out how to use Audacity before you continue to say things that make you look stupid.

/MODERATION

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #29
Okay, I just had to create an account in case someone like me wants to find out if FLAC is truly lossless and ends up in this crazy thread. None of the commands recommended to the OP have any relevance to whether or not the FLAC files are going to have the same quality as the original .wav or .aif files. They will merely show whether or not the different compression settings for the FLAC files contain the same amount of information when output.

To find out if your original files and FLAC files are identical in quality (which they should always be), all you have to do is  import the two files on separate tracks in any DAW (even Audacity, which is free),, and invert the phase on one. When you play the play the file, you should hear absolutely nothing. This is the only sure fire way to be positive you are getting exactly the same thing with the FLAC file as you are the .wav or .aif files. Phase inversion will cancel the audio signal out completely. This is how noise cancellation headphones work. If you've placed both files at the exact beginning of the project, leave all the volume and panning controls alone, and do nothing but invert one file, silence will tell you that you've got a perfect copy of your original. Anything you hear is different in one file or the other.

Just be careful if you use Audacity not to do anything with your original files. Changes you make with it are permanent. It's a destructive editor, meaning that it actually applies the changes you make in the program to the file you placed in it.

There's an even easier way to check a compressed file if it's the same as the original.
https://www.foobar2000.org/components/view/foo_bitcompare

In fact you can batch check 2 different sets quickly and efficiently for any errors and redo the affected files that didn't get converted properly.  No need to do anything more than that.  Very handy tool if you're switching your lossless library from one existing lossless format to a different one and have to convert thousands of files in the process.

On a side note: Why does this topic exist?  FLAC is lossless.

 

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #30
Okay, I just had to create an account in case someone like me wants to find out if FLAC is truly lossless and ends up in this crazy thread. None of the commands recommended to the OP have any relevance to whether or not the FLAC files are going to have the same quality as the original .wav or .aif files. They will merely show whether or not the different compression settings for the FLAC files contain the same amount of information when output.

To find out if your original files and FLAC files are identical in quality (which they should always be), all you have to do is  import the two files on separate tracks in any DAW (even Audacity, which is free),, and invert the phase on one. When you play the play the file, you should hear absolutely nothing. This is the only sure fire way to be positive you are getting exactly the same thing with the FLAC file as you are the .wav or .aif files. Phase inversion will cancel the audio signal out completely. This is how noise cancellation headphones work. If you've placed both files at the exact beginning of the project, leave all the volume and panning controls alone, and do nothing but invert one file, silence will tell you that you've got a perfect copy of your original. Anything you hear is different in one file or the other.

Just be careful if you use Audacity not to do anything with your original files. Changes you make with it are permanent. It's a destructive editor, meaning that it actually applies the changes you make in the program to the file you placed in it.

This is absurd and meaningless. First of all, there is not going to be any difference between the original file and the flac file, because flac is in fact a lossless format. And if you really need to see proof of that, you can simply decode a flac file and compare it to the original:
Code: [Select]
$ flac -o flacfile.flac original.wav
$ flac -o decoded.wav -d flacfile.flac
$
$ sha256sum original.wav decoded.wav
ccae65206b1b5320a7e19cc90c3b8ac8bb73d335be013e884bae7dcca3343c9d  original.wav
ccae65206b1b5320a7e19cc90c3b8ac8bb73d335be013e884bae7dcca3343c9d  decoded.wav
$

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #31
Gosh. Let me disregard the age of the original posting ...

Those who just go ahead and make the claim that the conversion will be lossless, can download this .wav file, convert it to FLAC using foobar2000 and bit-compare. Guess what.
Then they can open a command-line window and try to do the same using flac.exe.

The OP was not using flac.exe directly, the OP was using a given application with given settings. Did anybody test whether that application with those settings shown in the screenshot, actually do what flac.exe would do? Or perhaps what foobar2000 would do? (Which I think should be considered a bug, by the way. @Peter , are you there?)
Memento: this is Hydrogenaudio. Do not assume good faith.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #32
Gosh. Let me disregard the age of the original posting ...

Those who just go ahead and make the claim that the conversion will be lossless, can download this .wav file, convert it to FLAC using foobar2000 and bit-compare. Guess what.
Then they can open a command-line window and try to do the same using flac.exe.

The OP was not using flac.exe directly, the OP was using a given application with given settings. Did anybody test whether that application with those settings shown in the screenshot, actually do what flac.exe would do? Or perhaps what foobar2000 would do? (Which I think should be considered a bug, by the way. @Peter , are you there?)


The OP of this very old thread was just confused about what lossless compression means and was also suffering under the very normal placebo effect (induced by bad advice from his acquaintances, about how converting files *always* leads to some reduction in quality).

There's no reason to assume that the files he created with XLD weren't perfectly identical encodings and I don't think there's much point in investigating the behaviour of a certain piece of software from >6 years ago.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #33
There's no reason to assume that the files he created with XLD weren't perfectly identical encodings

Is there any reason to assume that files created with foobar2000 are not perfectly identical?
Memento: this is Hydrogenaudio. Do not assume good faith.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #34
Is there any reason to assume that files created with foobar2000 are not perfectly identical?

No, of course not. Why are we even talking about Foobar2000? As far as I can see people only suggested fb2k's bit comparator plugin to verify the validity of the encodes... which is a good idea.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #35
@Porcus Peter is well aware that there are theoretical audio formats that can't be piped through the player losslessly. Fortunately no one in their sane minds uses 32-bit integer or 64-bit float as audio format. You may find some comfort in knowing that the next version will report in properties whether a 32-bit file is in float or integer format.

PS: Even audio editors I have (Adobe Audition CS6 and latest Audacity) will simply load the file quietly as 32-bit floating point. No one should be surprised as 32-bit integer format is pure insanity. 32-bit float won't clip and it will still allow 150 dB of bit-perfect dynamic range in the non-clipping range.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #36
Just be careful if you use Audacity not to do anything with your original files. Changes you make with it are permanent. It's a destructive editor, meaning that it actually applies the changes you make in the program to the file you placed in it. I recommend downloading...

TOS 14.

That is entirely false! Audacity absolutely does NOT destructively change the original files you load in it.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #37
It's a destructive editor, meaning that it actually applies the changes you make in the program to the file you placed in it. I recommend downloading [..] That way you're sure to keep your original files safe.
You would still have to press Save in a destructive editor (like Sound Forge) to commit any changes. Working on a sound file is as safe as working in a word processor. A DAW is called non-destructive because edits like trims and deletions are just instructions in a project file, and could be tweaked or undone in the future. But a DAW doesn't usually provide accurate sample-level editing capabilities, effects are typically realtime and hard to apply to a selection. An audio production application doesn't replace a destructive stereo editor. I never used Audacity, but heard that is also project-based, with export/eender, like a mixture between the two types.

Sound Forge and Izotope RX will open and show 32-bit int files, such as those output by SoX. Compressing these temporary work files losslessly is a waste of time though.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #38
I vote for closing this nonsense thread.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #39
@Porcus Peter is well aware that there are theoretical audio formats that can't be piped through the player losslessly.
And - at least sometimes - issue transcoding warnings. It should warn here too. The infamous "lossless is lossless!" does not have credibility if lossless isn't lossless.

I raised this very question back in 2011, and the reactions were quite hostile. First to me for even asking, and then to where it was due. Violating the "lossless is lossless" maxime without warning is bad and unnecessary.
Memento: this is Hydrogenaudio. Do not assume good faith.

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #40
foobar2000 also doesn't show any warning for 24->16 bit transcoding, or when some DSP is active, or when RG is applied during transcoding. Should it?

Re: Is FLAC really lossless? / Do compression settings make a difference?

Reply #41
foobar2000 also doesn't show any warning for 24->16 bit transcoding, or when some DSP is active, or when RG is applied during transcoding. Should it?
You have to actively choose to output to 16 bits, or to apply some DSP or to change volume. Just like if I re-dither 16 -> 16 bit transcoding, right?
Memento: this is Hydrogenaudio. Do not assume good faith.

 
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