MP3 files have permanent data loss, right?

[DJJR]

Hi,

I know these are really basic questions, but I don't think I quite understand the process of burning MP3 files onto a CD.

If I am wrong about my first assumption it will clear up a lot of things. The questions are all very similar and related and someone may be able to answer them all by just helping me to understand more about the file types and the conversions that take place when making a standard CD from MP3 files.


1.) I have assumed that an MP3 file isn't just compressed, but that data has been permanently removed from the file and is lost forever. Is this true?

2.) If I make a CD with MP3 files and I make it to play as a regular CD, not a MP3 CD, then the songs on the CD are in a different format, but they haven't been reconverted to true wave files or lossless files, correct?

3.) I have made many CDs in the past and some of the older ones were made with MP3 files and the newer ones have been made with WAVE files. I didn't lable the CD well and therefore on some CDs I don't know what kind of files I began with. When I view the CD songs' properties they all look similar. All of the files are listed as cda or something similar. dbPowerAmp labels them as cda and lists them as "CD" files on the player even though the original files were MP3s.

When looking at the properties of a song file on a CD, is there a way to determine what type of file the original file was a MP3 or a Wave file?

4.) I did a test to see if I could distinguish between two files of the same song where one was a 128 kbps and the other was a 320 kbps. When I look at them on the player they are both the same size. Does this mean they have been converted to the same quality file?

5.) If I record three songs that have three different file types - a 128 MP3, a 320 MP3 and a WAVE file and burn them onto a CD into a standard 80 minute CD format, what will be the difference in quality on the final CD between these three songs.

Thanks a bunch to anyone who can help me understand this better.

DJJR

[DudeBoyz]

Re: MP3 files have permanent data loss, right?

Item 1 - yes - that is true. MP3 is a LOSSY compression, like JPG is for graphics files, and the TRUE data is indeed lost. Fill-in data can be guestimated using Interpolation, but it is an imperfect option at best. For all intents and purposes, once the data is gone, the data cannot be re-introduced by conventional methods, and it still won't necessarily (probably not at all really) true to the original.

Item 2 - When you take those MP3 files and burn them to an audio CD, it converts the data to a non-compressed format, but they are not lossless. They can only contain as much information as the MP3 provides, unless they are interpolated.

Item 3 - I am not sure if there is, but it doesn't necessarily matter, as once they are converted back to CDA (CD Audio), they all look alike, generally. It is BEST if you can rip from the original source material to a LOSSLESS Format like FLAC for storage on your drive, should you want custom compilations to maintain full quality when burned to CD. Not all people have a discerning ear, so they do not mind, but some folks do - especially when listening with headphones.

Item 4 - I guess you could look at the WAVEFORM representation of both files and see which one has more frequencies missing. I think that would be a rather long and tedious process, however, but I think it could be done.

Item 5 - The raw WAVE file should provide you with the best quality. The WAVE file should not have any data removed during the ripping/recording process. However, both the 320kbps and 128kbps files WILL have data removed. The 128kbps will have MORE data removed than the 320kbps, but both will still not be 100% true to the original recording. A raw, uncompressed WAVE file should be 100% true, however, but can take up tons of space. Even if you were to try using a loss-less compression form of a WAVE file, it can still take tons of space.

If you want LOSSLESS, a lot of folks recommend the FLAC format. It appears highly thought of and very functional.

MP3's are about compromise between Quality and Size. I find that 160kbps files done with the Fast Fraunhoffer method sound just as good to me as 192kbps files created with the LAME encoder, but my tastes and ears may be just a bit different from others out there. All our bodies are unique and some hear better than others.

So when I rip Music CD's, I use Music Match 7.5, which has that Fast Fraunhoffer codec, and I rip all of those at 160kbps.

If I can't use Music Match for whatever reason, I use AudioGrabber with the latest LAME codec at 192kbps, and those are both free. dbPowerAmp can probably do about everything that AudioGrabber can, so many people have switched over to it. In fact, I'm sorta in the process of doing that too, especially since the Version 12 release will have the latest 3.97 FINAL version of LAME included.

Best of luck with your audio!


Note - under a straight conversion, taking a 128kbps MP3 and re-sampling it to 320kbps will not give you better quality. It can only work with the data that is there. Again, interpolation may help, but I'm not a fan of letting the computer guess what to put in there. So if you RIP at 128, it's best to leave it at 128 on the computer. If you make a CD Audio disk, it will have the same quality but simply be uncompressed.

[DJJR]

Re: MP3 files have permanent data loss, right?

Thanks for the feedback. I have been using the .ape format for the lossless files which still gives me some compression for less disk usage. So all my new CDs will be fine, but it is just that with my older CD recordings, if I want to insure that the music quality is lossless, I will need to re-record them.

Thanks,

DJJR