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Topic: How do you determine which compression level was used? (Read 14488 times) previous topic - next topic
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How do you determine which compression level was used?

HI everyone. I didnt want to post the few ?s i have seperatley so i just chose the FLAC topic and hope no one minds. Any help with any of this is greatly appreciated. I am trying to rip all my cds with EAC, encode with FLAC and access them with Foobar and have a .cue, log and ffp with every album. I am still new to alot of this and short on time (working 80+ hours a week) I try to read as much as i can to find my answers but these are the things that have me stuck. Since this is the FLAC topic i will ask this 1st - is there a way to tell what compression level (i.e. -1, -2, etc.)was used for an album encoded in FLAC that you did not encode yourself? I keep mine @ -8 and don't want to have to re-encode any albums i have not encoded myself just to be sure. Second question - cue sheets.  I'm very new to them. What (if any) tag properties can i change after creating a cue sheet without having to edit the cue sheet for it to do its job? As far as I can tell a .cue for a multiple file album is just for the correct gaps when burning(and maybe CD text, idk), so will it mess it up if i change anything exept the filename  (i.e. the genre) on the files tags? 3rd question - i use an old version of EAC (v0.95b3) for the retrieve native TOC feature. This is the only way i know to make the .cue for a CD with a data track @ the end, w/o including the data track in the .cue. Is there a way to do this with newer versions of EAC? Well thats all besides foobar i can think of right now but i will find the appropriate forum for that. thanks ahead of time for any help

How do you determine which compression level was used?

Reply #1
hi quickly
1: no you can't unless it's written in the tag , I already asked Josh about this, his anwser was that it was useless ... to his mind it is useless to store this info as settings are linked to parameters which can change between versions.
2: you can change almost anything as long as you don't mess with timing & the architecture of the cue ... fixing name & genre typo is safe
3: I don't know I always delete data track
see ya

PS: don't use flac -8 it's a lot slower for almost no size gain use either 5 or 6 ... flac is almost a single setting codec that's also why it's useless to keep the setting info.

How do you determine which compression level was used?

Reply #2
Quote
1st - is there a way to tell what compression level (i.e. -1, -2, etc.)was used for an album encoded in FLAC that you did not encode yourself?


Well yes and no. It's called "Mr. QuestionMan". All you need to do is search for the files on your hard-drive and it will tell you what encoder version of FLAC was used and what the bitrate is. It can't tell you exactly what compression level setting was used with lossless files though. It can only do that with lossy encoders like MP3 and Vorbis. 

Quote
I keep mine @ -8 and don't want to have to re-encode any albums I have not encoded myself just to be sure.


Lossless is lossless. It doesn't matter how old the reference encoder is. The most common compression level with FLAC is --compression-level 5. In any event if you want to make sure that the files are encoded with the newest reference encoder you can transcode all of the files using the Foobar2000 converter to --compression-level 8 for instance which uses the latest FLAC reference encoder. That's what I would recommend doing at least. 
budding I.T professional

How do you determine which compression level was used?

Reply #3
. The most common compression level with FLAC is --compression-level 5. In any event if you want to make sure that the files are encoded with the newest reference encoder you can transcode all of the files using the Foobar2000 converter to --compression-level 8 for instance which uses the latest FLAC reference encoder. That's what I would recommend doing at least.

I wouldn't.
The tiny size reduction's not really worth the time involved in my opinion.

How do you determine which compression level was used?

Reply #4
3rd question - i use an old version of EAC (v0.95b3) for the retrieve native TOC feature. This is the only way i know to make the .cue for a CD with a data track @ the end, w/o including the data track in the .cue. Is there a way to do this with newer versions of EAC?

Hi.

I recently reripped some enhanced CD's in my collection just to configure my setup and verify the settings for my drives (had to reinstall Windows little earlier).
Something I noticed was that if one just commands EAC to copy image and create cue sheet with a such CD, it will leave out the last data track by default.
The last track isn't read by EAC nor its indexes are written to cue sheet. I'm not sure if this applies to every single occasion of these CD's with data tracks, it's hard to prove so. It just works for me.

The version used is EAC v0.99pb5 from some forum where andre was asking for beta testing some time ago.

Edit: The link to the v0.99pb5 is here: http://www.exactaudiocopy.de/EACBeta.zip Just extract the contents to your EAC directory, previous install needed!
NB: It's still in beta phase and not officially released in the EAC homepage, don't blame me if this renders your PC useless
Hevay is The Way!

How do you determine which compression level was used?

Reply #5
I think he's talking about the problem that arises when EAC detects a pregap before the data session and puts a 00 index for it in the CUE sheet.

Here's an example:
Code: [Select]
FILE "14 - Last Audio Track.wav" WAVE
    INDEX 01 00:00:00
  TRACK 15 MODEx/2xxx
    INDEX 00 03:43:50

How do you determine which compression level was used?

Reply #6
Didn't know that.
Sorry, my mistake.
Hevay is The Way!

How do you determine which compression level was used?

Reply #7
Quote
I wouldn't.
The tiny size reduction's not really worth the time involved in my opinion.


Your mistaken. I am not saying that I use it personally. I actually use --compression-level 3. I have no need to use anything greater that then that as I have a ton of hard-drive space. If anything I wouldn't use beyond --compression-level 6. I don't know what most people do anyhow. I hope that helps to clarify things.
budding I.T professional

 

How do you determine which compression level was used?

Reply #8
Quote
I wouldn't.
The tiny size reduction's not really worth the time involved in my opinion.


Your mistaken. I am not saying that I use it personally. I actually use --compression-level 3. I have no need to use anything greater that then that as I have a ton of hard-drive space. If anything I wouldn't use beyond --compression-level 6. I don't know what most people do anyhow. I hope that helps to clarify things.

If you're dealing with slower hardware and reencoding from flac -5 to flac -8, it doesn't make sense. On my EEEPC, flac -8 encodes at about 6.7x and is less than 0.5% smaller than flac -5
On the other hand, it's also about 8% smaller than flac -0.
As I suspect that most flac encoding is at -5 or higher*, I'm pretty sure you're mistaken.

All testing done on Debian Sid using flac1.2.1 as packaged by Debian and doesn't consider any changes in compression efficiency over older versions.


*No real proof for this, just a hunch


How do you determine which compression level was used?

Reply #10
And, as an addendum to my previous test, flake 0.10 -12 is essentially equal to flac 1.2.1 -8 compression-wise but barely compresses in realtime.

And it's not really a matter of being "mistaken".
It's more of a tradeoff of time vs storage space.

How do you determine which compression level was used?

Reply #11
Quote
If you're dealing with slower hardware and reencoding from flac -5 to flac -8, it doesn't make sense. On my EEEPC, flac -8 encodes at about 6.7x and is less than 0.5% smaller than flac -5
On the other hand, it's also about 8% smaller than flac -0.
As I suspect that most flac encoding is at -5 or higher*, I'm pretty sure you're mistaken.


Again I AM NOT transcoding from -5 to -8. The original poster is. I really don't know how slow or fast it will be to be honest with you. The only reason I recommended that was, because the original poster wanted to know if it was possible to do that. This is the way I interpreted it at least. I wasn't speculating on how efficient it would be just that it is possible. 


Quote
And it's not really a matter of being "mistaken".
It's more of a tradeoff of time vs storage space.


Right which is why I use -3. 
budding I.T professional

How do you determine which compression level was used?

Reply #12
Quote
If you're dealing with slower hardware and reencoding from flac -5 to flac -8, it doesn't make sense. On my EEEPC, flac -8 encodes at about 6.7x and is less than 0.5% smaller than flac -5
On the other hand, it's also about 8% smaller than flac -0.
As I suspect that most flac encoding is at -5 or higher*, I'm pretty sure you're mistaken.


Again I AM NOT transcoding from -5 to -8. The original poster is. I really don't know how slow or fast it will be to be honest with you. The only reason I recommended that was, because the original poster wanted to know if it was possible to do that. This is the way I interpreted it at least. I wasn't speculating on how efficient it would be just that it is possible. 


I never disagreed that it was possible.
I just said it wasn't really worth it.

How do you determine which compression level was used?

Reply #13
I appreciate the responses and -8 does take a long time so i will experiment with -5 or -6 and look @ the size difference. Only reason i was aiming for maximum compression was to use the files on an ipod with rockbox. As for the other issues for some reason when i use EAC it does read the data track and include it in the cue (as well as the index), hence the reason i use 0.95b3, so i will prob just stick with that one. Good to know I can change the metadata without having to edit the cue - it worried me. I recently came upon a guide to loading the cue in EAC as if you were about to write a disc that works as a test, so I will try that when I have the time. Thanks again everyone 

How do you determine which compression level was used?

Reply #14
So... just to make sure I got this right:  The 8 different compression levels of FLAC are essentially the same quality... the differences being that you can have a slightly larger file (but takes longer to encode), or you can have a slightly smaller file (but encoding time is quick)?  The actual sound quality is generally unaffected?

How do you determine which compression level was used?

Reply #15
FLAC is LOSSLESS.

Cheers, Slipstreem. 

How do you determine which compression level was used?

Reply #16
the differences being that you can have a slightly larger file (but takes longer to encode), or you can have a slightly smaller file (but encoding time is quick)?

No.
0 is the fastest but gives the largest file sizes
8 is the slowest but gives the smallest file sizes.


How do you determine which compression level was used?

Reply #18
The actual sound quality is generally unaffected?

No, the sound quality is always unaffected.


OK, so a 0 FLAC will sound the same as an 8 FLAC... the only reason one would wish to select one level over the other is based on personal preferences in size of the file and encoding time.  I personally just use level 5 (the default), but I was curious as to what exactly the 8 different compression levels meant.

How do you determine which compression level was used?

Reply #19
OK, so a 0 FLAC will sound the same as an 8 FLAC... the only reason one would wish to select one level over the other is based on personal preferences in size of the file and encoding time.  I personally just use level 5 (the default), but I was curious as to what exactly the 8 different compression levels meant.


Hello friends. My English is not very good.
I have a WAV file using the FLAC Frontend to convert it.
Converti using level 8 and level 0.
Why have had to play in different kbps foobar2000?
What has more quality?
Level 0 - 1021 kbps - 25.5 MB
Level 8 - 936 kbps - 23,4 MB

http://img13.imageshack.us/my.php?image=kbps.jpg

Thank you.
I look back
Thanks from Brazil



How do you determine which compression level was used?

Reply #20
Hi there and welcome to hydrogenaudio!

FLAC is lossless - there is no difference in *quality* between the different levels, only compression.
lossyWAV -q X -a 4 -s h -A --feedback 2 --limit 15848 --scale 0.5 | FLAC -5 -e -p -b 512 -P=4096 -S- (having set foobar to output 24-bit PCM; scaling by 0.5 gives the ANS headroom to work)

How do you determine which compression level was used?

Reply #21
They are both the same quality.

How do you determine which compression level was used?

Reply #22
Hi there and welcome to hydrogenaudio!

FLAC is lossless - there is no difference in *quality* between the different levels, only compression.


Thanks Nick.C
But because 1021 and 936 kbps?
This is compression?
Kbps indicates what?



How do you determine which compression level was used?

Reply #23
kbps indicates the compressed bitrate of the FLAC file, i.e. 1021kbps = 1,021,000 bits per second, or 127625 bytes per second. However, as FLAC is lossless, the bitrate of the uncompressed audio is 1411.2kbps when it is played (assuming 16bit 44.1kHz 2 channel PCM audio input). Your player displays the compressed bitrate.

Basically, level 8 takes more time by trying harder to compress the data. The uncompressed output of a level 0 and a level 8 version of the same input file will be identical, i.e. the same as the input file.
lossyWAV -q X -a 4 -s h -A --feedback 2 --limit 15848 --scale 0.5 | FLAC -5 -e -p -b 512 -P=4096 -S- (having set foobar to output 24-bit PCM; scaling by 0.5 gives the ANS headroom to work)

How do you determine which compression level was used?

Reply #24
kbps indicates the compressed bitrate of the FLAC file, i.e. 1021kbps = 1,021,000 bits per second, or 127625 bytes per second. However, as FLAC is lossless, the bitrate of the uncompressed audio is 1411.2kbps when it is played (assuming 16bit 44.1kHz 2 channel PCM audio input). Your player displays the compressed bitrate.

Basically, level 8 takes more time by trying harder to compress the data. The uncompressed output of a level 0 and a level 8 version of the same input file will be identical, i.e. the same as the input file.



Very Very Thanks !