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Full Version: "Fake" FLAC check wanted please.
Hydrogenaudio Forums > Lossless Audio Compression > FLAC
JOmega
I'm paranoid that I have a FLAC that was just converted from MP3. I tried using an AudioChecker tool but it didn't work properly. I also do not know how to decode it to a .wav file so I was wondering if someone would be kind enough to help me.

They both look (and sound) very similar to me and have a cutoff around 20 when I look in Foobar's spectrum. However, I'm no official and would like to think that it is truly a "real" FLAC.

It would be much appreciated! Thanks.

Moderation: Removed poster's request that people break TOS #9. Unless you demonstrate that this flac is not subject to copyright, you will not be allowed to use this forum as a vehicle for file transfer!
Mike Giacomelli
You'll need the WAV version, not the MP3 version. Compare the output of the WAV and FLAC version of the song and see if they're bit per bit identical (a tool like foobar2000 can do this).
pdq
If the FLAC was created from the identical mp3 then decoding both to WAV and bit comparing them could be useful, otherwise not.

BTW, if he had the original WAV version to compare to then he wouldn't need the mp3 or the FLAC.
DVDdoug
QUOTE
I also do not know how to decode it to a .wav file
I don't use foobar, but I'm pretty sure foobar can do that... Or, XRECODE is an easy-to-use format converter. (Here is a link to the older FREE version of XRECODE.)

I don't use AudioChecker either, but I think it can only give you a probability that a file is transcoded from a lossy format. Without the original WAV, I don't think there's any way to prove that a file was compressed/altered. Even if you hear artifacts/defects, those artifacts/defects might be present in the original.
dv1989
QUOTE (pdq @ Jul 17 2009, 19:11) *
If the FLAC was created from the identical mp3 then decoding both to WAV and bit comparing them could be useful, otherwise not.

BTW, if he had the original WAV version to compare to then he wouldn't need the mp3 or the FLAC.

Also, the same decoder and settings would have to be used, so that method is almost totally unusable.
John Connor
Can you supply us with a screenshot of the spectrum from AA or Audacity?
EricPost
Here's is a site with a very easy tool for decoding FLAC

http://members.home.nl/w.speek/flac.htm

At the bottom are other front ends for other formats.

JOmega
QUOTE (John Connor @ Jul 18 2009, 08:02) *
Can you supply us with a screenshot of the spectrum from AA or Audacity?


What is AA? And is Foobar okay? >_>

And sorry for trying to break ToS... it's just upsetting thinking that I have fake ones. And I'm kind of technical-detail-music-retarded so if I have an mp3 and a FLAC of the same song could someone post like a simple step-by-step for me please to find out if there is a difference? Or if the FLAC is a true FLAC from the original?
Mike Giacomelli
QUOTE (JOmega @ Jul 19 2009, 00:01) *
And I'm kind of technical-detail-music-retarded so if I have an mp3 and a FLAC of the same song could someone post like a simple step-by-step for me please to find out if there is a difference? Or if the FLAC is a true FLAC from the original?


As I said in the first sentence of the first reply to this thread, no. Having an MP3 copy doesn't help you figure out if the FLAC is direct from the original. You need a copy of the original to determine that.
Edu Camargo
Hey, it's been so long. Glad to be back on HA. And hi to most of you. Nice to meet you guys.

I don't know if my suggestion will serve, but anyway. If you have a tool like "Sound Forge" you could invert the phase of the audio. This way you could determine if this flac was created from a lossy source, since every center material is removed, leaving only the L+R information, and also, you can hear with more precision the artefacts generated by the compression. I presume this is one of the alternatives to determine if your file is from a lossy source without having the original material.

By the way, Sound Forge 9 supports flac.

In Sound Forge, clicking the "process" menu, and "channel converter", you have three presets that work with phase inverting: "mono to stereo - invert phase psuedo-stereo", "stereo to mono - use diference between channels", and "stereo to stereo - vocal cut remove center material". Of course, if you don't have sound forge, there are other alternatives that might help you in this process.

HTH.

Peace, Edu.
odyssey
If you have an entire album, you can check with CUETools to see if it's found in AccurateRip DB.
gregory
QUOTE (odyssey @ Jul 19 2009, 07:19) *
If you have an entire album, you can check with CUETools to see if it's found in AccurateRip DB.


I'm glad I've found this thread. Can you explain how CUETools accomplishes this. I'm ignorant here, but doesn't AccurateRip use crc values for comparison? What do cue sheets have to do with that. I'm confused.
odyssey
CUEtools has been it's name since it's early days. Initially it was a tool that could do different things with CUE-sheets and files, such as convert between cue/image and single-track files.

Today it does a lot more than just that. You can generate cuesheets from set of files and/or use it to verify accuraterip based on this information. It's very automatic. You should give it a try.
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