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Audio fidelity and compression?

post #1 of 7
Thread Starter 

Hi there, first of all I have bought my own original copy Demon Days by Gorillaz many years ago, however I have recently use dbamppower to rip it to FLAC at level 8. I have also downloaded a FLAC version of the album from piratebay for research purposes. I have noticed that the songs from the piratebay version is compressed by 55%, so my questions is do I lose any audio fidelity in the piratebay version? does it say compressed because it was ripped with a lower level, when compared to my uncompressed ripped version?

 

Pls ignore the kpbs, I think it's bugged I have use foobar and winamp to check it, and my ripped version is almost two items the size in kpbs of the piratebay's one. 

 

post #2 of 7

Bitrate is that of the decoded (decompressed PCM) song, so that's fine albeit confusing.

 

The length of the tracks are different, so I'd be careful. Unless you can verify that the rip was made cleanly from a CD anything could have happened to the files (transcoded from mp3, edited/cut, different version ...).

post #3 of 7

The entire point of FLAC is so you can compress the file without losing fidelity. Compression only effects encode/decode speed. The decode time is extremely small regardless of compression so it's negligible, and the encoding is a one time thing.

post #4 of 7
Thread Starter 
Quote:
Originally Posted by xnor View Post
 

Bitrate is that of the decoded (decompressed PCM) song, so that's fine albeit confusing.

 

The length of the tracks are different, so I'd be careful. Unless you can verify that the rip was made cleanly from a CD anything could have happened to the files (transcoded from mp3, edited/cut, different version ...).

Yeah I sjtu noticed about the length but like I say I took that one from piratebay so I have no idea whether it's really ripped from CD or not however mine is definitely ripped from an original CD 

Quote:
Originally Posted by chewy4 View Post
 

The entire point of FLAC is so you can compress the file without losing fidelity. Compression only effects encode/decode speed. The decode time is extremely small regardless of compression so it's negligible, and the encoding is a one time thing.

So are you saying there should be no difference in audio quality between these two files? 

post #5 of 7
Quote:
Originally Posted by chee006 View Post
 

So are you saying there should be no difference in audio quality between these two files? 

If they were from the same source, yeah compression settings on FLAC have no effect on audio quality. 1 and 8 sound the same, they have identical playback.

 

But like xnor said who knows where the one you downloaded has been.

post #6 of 7
Thread Starter 
Quote:
Originally Posted by chewy4 View Post
 

If they were from the same source, yeah compression settings on FLAC have no effect on audio quality. 1 and 8 sound the same, they have identical playback.

 

But like xnor said who knows where the one you downloaded has been.

 

I see thanks for the info, but what about the kpbs? does that make a difference? 

post #7 of 7
Quote:
Originally Posted by chee006 View Post
 

 

I see thanks for the info, but what about the kpbs? does that make a difference? 

 

Not at all. It's just a ratio of file size to time. It's always going to be lower if the file is compressed because the file size is smaller.

 

In an uncompressed file it is the product of sample rate, channels and bit depth. So for a CD quality file it is 44.1kHz * 2 * 16 = 1411kbps. 

But when the file is compressed using lossless compression it makes bitrate a meaningless number in regards to audio quality. 

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