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File size / quality questions and more...
mark-7722
post Oct 30 2013, 00:35
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Forgive me for the basic questions, but I know very little about audio files and ripping CD's. Please bear with me.


I've ripped a LOT of cd's to FLAC using AIMP3 on a Windoze box. Today I ripped a CD on my Linux box using k3b and notice the file sizes were quite different (about 50% smaller), so I grabbed a CD I had already ripped w/ AIMP3 and ripped it again in linux to compare the difference.
Here's the basic info (again, ripping to FLAC)
Folder with the files ripped on windows
-the files range from 11.1 MB - 14.4 ( total 271.3 Mb)
Folder with the files ripped on Linux:
-the files range from 5.4 MB - 7.0 ( total 132.6 Mb)

1) I thought FLAC was lossless so all files would be the same. What am I missing? A 50% storage savings is an amazing difference.

2) If I truly can save ~50% of disk space, do I now have to go back and re-rip my entire existing work, or can I run some compression on the previously ripped files and see this size reduction?
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saratoga
post Oct 30 2013, 02:18
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The files on the linux system are probably not FLAC given the file sizes.
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A_Man_Eating_Duc...
post Oct 30 2013, 02:22
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Have you tried ripping the same song on each OS and then doing a file compare on the files?

you can use Foobar and the foo_bitcompare plugin.

This post has been edited by A_Man_Eating_Duck: Oct 30 2013, 02:23


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Makaki
post Oct 30 2013, 03:32
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QUOTE (saratoga @ Oct 29 2013, 21:18) *
The files on the linux system are probably not FLAC given the file sizes.


I would trying the linux "file" command, which will tell you what type of file it is based on the contents
$ file myfile.flac

Alternatively, you could listen to the file on a player that can report file details. The file information will tell you what codec was used, bitrate, etc.
Examples: VLC, Foobar, Winamp
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pdq
post Oct 30 2013, 03:57
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If both files are accurately encoded FLAC files and the only difference is the degree of compression, there is no need to rerip. You can just reencode the big files into little files losslessly.

Having said that, I find it very unlikely that there would be a factor of two size difference when encoding from from the same source file. The file size just doesn't vary that much with the compression setting.
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Nessuno
post Oct 30 2013, 08:01
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QUOTE (mark-7722 @ Oct 30 2013, 01:35) *
Here's the basic info (again, ripping to FLAC)
Folder with the files ripped on windows
-the files range from 11.1 MB - 14.4 ( total 271.3 Mb)
Folder with the files ripped on Linux:
-the files range from 5.4 MB - 7.0 ( total 132.6 Mb)

Which original CD was the one ripped? 132Mb seems too little a lossless rip even for a small CD (for example a reissue of an old 45 min LP). If the Linux files actually play, decode both to wav and bit compare the results. Maybe something is wrong in your K3B configuration and they really are lossy files (even with a *.flac filename).


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phofman
post Oct 30 2013, 10:40
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My 2cents - k3b ripped to ogg.
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JJZolx
post Oct 31 2013, 01:18
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QUOTE (Nessuno @ Oct 30 2013, 01:01) *
Which original CD was the one ripped? 132Mb seems too little a lossless rip even for a small CD (for example a reissue of an old 45 min LP).

I have a number of mono jazz albums which compress down to as little as 18% of their original size using FLAC at -5. Ahmad Jamal's 1955 classic Poinciana is just one example. Most tracks are 18 to 19% of their original size, and the whole 12 track, 43 minute album is only 80.6 MB encoded in FLAC.
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DonP
post Oct 31 2013, 02:40
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QUOTE (Nessuno @ Oct 30 2013, 03:01) *
QUOTE (mark-7722 @ Oct 30 2013, 01:35) *
Here's the basic info (again, ripping to FLAC)
Folder with the files ripped on windows
-the files range from 11.1 MB - 14.4 ( total 271.3 Mb)
Folder with the files ripped on Linux:
-the files range from 5.4 MB - 7.0 ( total 132.6 Mb)

Which original CD was the one ripped? 132Mb seems too little a lossless rip even for a small CD (for example a reissue of an old 45 min LP). If the Linux files actually play, decode both to wav and bit compare the results. Maybe something is wrong in your K3B configuration and they really are lossy files (even with a *.flac filename).


I've had some solo piano compress (flac 5) to the high 200 kb/s. For some reason flac compresses piano really well. Lossyflac actually comes out larger due to the overhead of smaller blocks. Anyway, I think that comes to about 150 MB for an hour long CD.
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Nessuno
post Oct 31 2013, 09:23
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Just for this reason I was asking, before telling it impossible. wink.gif

Anyway, even if in this thread has emerged that some small differences are possible, if the same CD compress at double the rate simply changing implementation I think that the only sensible explication is that the smaller ones are lossy.


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mark-7722
post Oct 31 2013, 15:14
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Thanks for all the replies. Here's my answers to those who posed questions...


QUOTE (saratoga @ Oct 30 2013, 02:18) *
The files on the linux system are probably not FLAC given the file sizes.
I'm pretty sure they're both flac as linux has a tool called "file" that checks file types and it does report both files are .flac.

Also using Makaki's advice from a later reply, I did open both in VLC and they show .flac codec

QUOTE (pdq @ Oct 30 2013, 03:57) *
If both files are accurately encoded FLAC files and the only difference is the degree of compression, there is no need to rerip. You can just reencode the big files into little files losslessly.

Having said that, I find it very unlikely that there would be a factor of two size difference when encoding from from the same source file. The file size just doesn't vary that much with the compression setting.
I didn't realize FLAC used compression. I thought lossless formats couldn’t do that (Like I said, I'm completely uninformed on this topic).

How would one go about compressing a preexisting .flac file (linux tool would be helpful)?



QUOTE (Nessuno @ Oct 30 2013, 08:01) *
Which original CD was the one ripped? 132Mb seems too little a lossless rip even for a small CD (for example a reissue of an old 45 min LP). If the Linux files actually play, decode both to wav and bit compare the results. Maybe something is wrong in your K3B configuration and they really are lossy files (even with a *.flac filename).
It's an audio book (Lord of the Rings). The tracks are only 3-5 minutes.
As to trying the wav thing you recommend. I'd need a bit of help on how exactly that is done.

Since this is an audio book, and tracks are only a few minutes would linking to two copies of the same track be allowed as "acceptable use" similarly to pasting a small quote from a book is allowed? Perhaps if you folks who are knowledgeable looked at the files, we could get a more definitive answer?

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pdq
post Oct 31 2013, 15:59
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QUOTE (mark-7722 @ Oct 31 2013, 10:14) *
Since this is an audio book, and tracks are only a few minutes would linking to two copies of the same track be allowed as "acceptable use" similarly to pasting a small quote from a book is allowed? Perhaps if you folks who are knowledgeable looked at the files, we could get a more definitive answer?

Unfortunately HA's rules forbid posting or linking to clips of copyrighted material longer than 30 seconds.

This post has been edited by pdq: Oct 31 2013, 15:59
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probedb
post Oct 31 2013, 19:25
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QUOTE (mark-7722 @ Oct 31 2013, 14:14) *
I didn't realize FLAC used compression. I thought lossless formats couldn’t do that (Like I said, I'm completely uninformed on this topic).

How would one go about compressing a preexisting .flac file (linux tool would be helpful)?


Well it's all available if you look on the wiki here or just look up FLAC. It's lossless compression.

If it's a FLAC file you shouldn't need to, it should already be compressed.
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mark-7722
post Oct 31 2013, 20:07
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QUOTE (probedb @ Oct 31 2013, 19:25) *
If it's a FLAC file you shouldn't need to, it should already be compressed.

o.O I think one of us missed something.

If the files are ~2x larger... something didn't get compressed.

This post has been edited by mark-7722: Oct 31 2013, 20:08
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saratoga
post Oct 31 2013, 20:15
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QUOTE (mark-7722 @ Oct 31 2013, 15:07) *
QUOTE (probedb @ Oct 31 2013, 19:25) *
If it's a FLAC file you shouldn't need to, it should already be compressed.

o.O I think one of us missed something.

If the files are ~2x larger... something didn't get compressed.


FLAC is indeed compressed. If the files are 2x larger probably one of them is not what you think it is.
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lvqcl
post Oct 31 2013, 20:42
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QUOTE (saratoga @ Oct 31 2013, 23:15) *
If the files are 2x larger probably one of them is not what you think it is.

Why not? AFAIK flac -0 doesn't use mid/side encoding, so if input files are nearly mono there will be almost 2x difference between -0 and other encoding levels.
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probedb
post Nov 1 2013, 09:11
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QUOTE (mark-7722 @ Oct 31 2013, 19:07) *
o.O I think one of us missed something.

If the files are ~2x larger... something didn't get compressed.


Nope. FLAC uses compression. Go read about it on it's home page or the wiki here.

Why not just find a FLAC verifier tool and find out what it is?
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phofman
post Nov 1 2013, 10:27
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QUOTE (probedb @ Nov 1 2013, 10:11) *
Why not just find a FLAC verifier tool and find out what it is?


+1. Several days of discussing about a possible file format when the answer is just one command away, especially on linux. E.g. soxi filename
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skamp
post Nov 1 2013, 11:00
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soxi craps out if the file extension is wrong. ffprobe (from ffmpeg) works better, I think:

CODE
ffprobe -print_format 'default' -show_streams -select_streams 'a:0' FILE 2>/dev/null


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db1989
post Nov 1 2013, 19:52
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QUOTE (mark-7722 @ Oct 31 2013, 14:14) *
I didn't realize FLAC used compression. I thought lossless formats couldn’t do that (Like I said, I'm completely uninformed on this topic).
FLAC = Free Lossless Audio Codec. Lossless audio as a term connotes compression.

Or you could just read the first sentence about FLAC on the first page of its official site:
QUOTE
FLAC stands for Free Lossless Audio Codec, an audio format similar to MP3, but lossless, meaning that audio is compressed in FLAC without any loss in quality.


This post has been edited by db1989: Nov 1 2013, 19:53
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mark-7722
post Nov 6 2013, 16:48
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QUOTE (probedb @ Nov 1 2013, 09:11) *
QUOTE (mark-7722 @ Oct 31 2013, 19:07) *
o.O I think one of us missed something.

If the files are ~2x larger... something didn't get compressed.


Nope. FLAC uses compression. Go read about it on it's home page or the wiki here.
I know that now. I also read that FLAC can be set to 0 compression. Which I would venture a bet would create a larger file than one set to 8.



QUOTE
Why not just find a FLAC verifier tool and find out what it is?
You mean other than the one I posted about earlier in the thread?

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greynol
post Nov 6 2013, 18:16
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To be clear, "0 compression" is not the same as no compression, assuming you mean flac is being fed the -0 parameter. It is possible to create a flac with no compression, however.

That said I don't have any reason to doubt you might see a ~50% reduction in file size by switching from -0 to -8, depending on the source material.

This post has been edited by greynol: Nov 6 2013, 18:18


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mark-7722
post Nov 11 2013, 19:30
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QUOTE (greynol @ Nov 6 2013, 18:16) *
That said I don't have any reason to doubt you might see a ~50% reduction in file size by switching from -0 to -8, depending on the source material.

So after all the bickering, the original question stands.

I'll just re-rip the things obviously I asked in the wrong place.
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pdq
post Nov 11 2013, 19:40
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There is no need to re-rip, just recompress the files with -8 compression, or whatever compression you like.

Have you calculated what size the files would be if they were uncompressed, based on play time, bit depth, sample rate and number of channels? Perhaps then we could take a guess as to what is going on.
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probedb
post Nov 11 2013, 20:25
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QUOTE (mark-7722 @ Nov 11 2013, 18:30) *
So after all the bickering, the original question stands.

I'll just re-rip the things obviously I asked in the wrong place.


What bickering, people have been giving you solutions.

1. Check that the files are definitely FLAC, easy enough to do whatever the OS.
2. If they're FLAC with minimal compression just reencode as FLAC, they're lossless you won't lose anything.
3. If they're not FLAC then it depends if they're lossy or lossless, lossy, rerip, lossless then just encode to FLAC.
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