Jump to content
Search In
  • More options...
Find results that contain...
Find results in...
Killjoy_NS

UPSAMPLED FLAC files...??

Recommended Posts

Posted · Original PosterOP

Hi to all...
i've got a few questions regarding few songs I have in FLAC...

 

When I put them through Lossless Audio Checker, it says "UPSAMPLED".

What is UPSAMPLED anyway?

 

But when I open FLAC file in SPECTRO, it seems to me that FLAC is legit.

Is UPSAMPLED means that FLAC is not legit (mp3 source) or something else?

 

Few screenshots...

lac.png

spectro.png


I heard that coffee's good for my sex life.

 

It isn't.

It kept me awake through the whole damn thing!

I actually had to participate.

 

- Jeff Dunham -

Link to post
Share on other sites

Yeah, upsampled usually means it's from a lossy source. However, Lossless Audio Checker is not biblical truth. It's rather prone to false positives (or in this case, negatives).

If the spectrogram shows that it is indeed lossless (which I can't really see in the picture), then that's what you should roll with. 


Nova doctrina terribilis sit perdere

Audio format guides: Vinyl records | Cassette tapes

Link to post
Share on other sites
Posted · Original PosterOP

Interesting. Very.

I've got all Rammstein collection in FLAC (big fan) but that album Klavier is obviously fake.

Whole album is played on piano.

What is the meaning of CUTOFF in LAC?

 

P.S. I can see that Specto kicks in 22khz....

I thought that usually means that file is legit FLAC.


I heard that coffee's good for my sex life.

 

It isn't.

It kept me awake through the whole damn thing!

I actually had to participate.

 

- Jeff Dunham -

Link to post
Share on other sites
4 hours ago, Killjoy_NS said:

Interesting. Very.

I've got all Rammstein collection in FLAC (big fan) but that album Klavier is obviously fake.

Whole album is played on piano.

What is the meaning of CUTOFF in LAC?

 

P.S. I can see that Specto kicks in 22khz....

I thought that usually means that file is legit FLAC.

Cutoff is basically Lossless Audio Checker's way of telling you how it came to the conclusion that it's an upsampled piece of audio. 

If it's upsampled from an MP3, for example, there will be an artificial frequency cutoff. 

 

Take this as an example: 

1438288929_Anmrkning2019-05-21110431.jpg.66f57377331b66b77964a217fbb1faca.jpg

This is a rip from a pretty poorly dubbed cassette tape, and as you can see almost all activity stops after 10KHz. But Lossless Audio Checker still considers it a "clean" FLAC, since the cutoff isn't artificially done:

Untitled.png.f1cadbbfbb4be46d7046ed99a715252f.png

 

The spectrogram will do analysis of the full spectrum of the file- It won't limit itself to the parts of the spectrum that has actual information. You'd need to zoom in and analyse the the higher frequency range to see if there's any information at all. 

 

As said, Lossless Audio Checker is not a fool proof methode. Especially with classical music it's very hit'n'miss. 


Nova doctrina terribilis sit perdere

Audio format guides: Vinyl records | Cassette tapes

Link to post
Share on other sites

Is there such a checker for MP3 ? So you know if the file was compressed originally as 320kbps or just upscaled from some lower bitrate...

Link to post
Share on other sites
On 5/21/2019 at 12:44 PM, RejZoR said:

Is there such a checker for MP3 ? So you know if the file was compressed originally as 320kbps or just upscaled from some lower bitrate...

Spectro can give you a hint.  I did some searching on this in the past and everyone seems to agree that :

128kbps : cut-off at 16KHz

192 kbps : cut-off at 19KHz

320kbps : cut-off at 20KHz

 

That being said, I used fre:ac to convert my entire collection of CD rips from .flac to 320kbps .mp3.  The resulting .mp3 files are cut off anywhere between 15.6 and 17KHz instead of 20KHz, so I'll take the statement earlier in my post with a grain of salt.  I think the encoder also plays a role. 

 

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×