MP3s ripped from burned CDs

[so_la_la]

Hi,
back in the 1990s, when MP3s etc. were still far from ordinary I occasionally was presented with burned CDs from my friends which I subsequently used to rip into my computer using EAC or the like.
My question is:
How good would the quality of these "rerips" be? My guess is that even when the second rip is done carefully there still could be problems because the music has already been compressed in the first rip.
How do you deal with such music?
Thanks!

[phred]

Quality is in the ears of the beholder. If they should good to you, then they are good. Especially if you're not an audiophile. But I would not rip them again as each rip takes it another generation from the original.

EDIT: Corrected last sentence from "...I would rip them again..." to "...I would not rip them again..."

[so_la_la]

I wonder whether there is a programme that identifies a lack of quality by analysing the files themselves. I am aware of MBs possibility to sort tracks by bitrate but this is not what I mean.

Also many users in this forum talk about the superiority of v0-files as opposed to v1- or v2-files. I don't know what this means.

[phred]

Also many users in this forum talk about the superiority of v0-files as opposed to v1- or v2-files. I don't know what this means.

That refers to the quality of the rip. If you've got an mp3 file, you do not want to rip it again. As stated above, each time you rip a rip, you're compressing something that has already been compressed. Each subsequent rip causes a degradation in sound quality. Whether or not you can hear the degradation depends on your own ears.

Take a look at this for general info http://wiki.hydrogenaud.io/index.php?title=LAME#Technical_information
and this for specifics on the various settings available http://wiki.hydrogenaud.io/index.php?title=LAME#Understanding_the_bitrate_settings

[frankz]

Hi,
back in the 1990s, when MP3s etc. were still far from ordinary I occasionally was presented with burned CDs from my friends which I subsequently used to rip into my computer using EAC or the like.
My question is:
How good would the quality of these "rerips" be? My guess is that even when the second rip is done carefully there still could be problems because the music has already been compressed in the first rip.
How do you deal with such music?
Thanks!

If the burned CDs were simply copies of other CDs (in other words, the friend copied the CD directly without any processing done to the files), then the sound quality on the burned CD will be exactly the same as if it were a store-bought CD.  If you were to rip those to MP3 now, it would be exactly the same as ripping a bought CD.

If the CDs were made from MP3 sources (in other words, the friend has some MP3, converted those to WAV and then burned those WAV files to CD), the sound quality on the CD will be MP3 quality.  In the 90s, 128kbps MP3s were pretty standard.  They will sound compressed on the CD.  If you were to rerip those and compress them to MP3 again, the sound quality will be absolutely terrible.  

Double compression like this is never good.  320kbps->WAV->320kbps may be somewhat listenable. 128kbps->WAV->anything will be filled with compression artifacts (a garbly sound).  

Very basically, V0, V1, V2 refer to the Lame Variable Bitrate Preset used when converting to MP3.  Variable Bitrate means more bits are used for more complex passages and less for less complex passages.  V0 is the highest quality variable bitrate preset, and V9 is the lowest.  You can also rip to Constant Bit Rate, using the same number of bits to compress simple passages as you do to compress complex passages and wasting a lot of space in the process.  Read phred's links for the technical details.

Programs like Audiochecker (https://www.freewarefiles.com/Audiochecker-Beta_program_21299.html) and Lossless Audio Checker (http://losslessaudiochecker.com/#downloads) try to guess whether a file is from a lossless (CD / FLAC, etc) source.  In other words, if you rip a CD to wav or flac and put the wav or flac into those programs, it guesses if the source of that file is lossless. It checks how much information is present in certain frequency ranges in the file that should be present in lossless sources but are missing due to compression in MP3 files. There is some debate as to how reliable this method is, but I've found it works reasonably well. 

[so_la_la]

That refers to the quality of the rip. If you've got an mp3 file, you do not want to rip it again. As stated above, each time you rip a rip, you're compressing something that has already been compressed. Each subsequent rip causes a degradation in sound quality. Whether or not you can hear the degradation depends on your own ears.

Take a look at this for general info http://wiki.hydrogenaud.io/index.php?title=LAME#Technical_information
and this for specifics on the various settings available http://wiki.hydrogenaud.io/index.php?title=LAME#Understanding_the_bitrate_settings

Thanks for the links!

If the burned CDs were simply copies of other CDs (in other words, the friend copied the CD directly without any processing done to the files), then the sound quality on the burned CD will be exactly the same as if it were a store-bought CD.  If you were to rip those to MP3 now, it would be exactly the same as ripping a bought CD.

As you might imagine I cannot remember...

If the CDs were made from MP3 sources (in other words, the friend has some MP3, converted those to WAV and then burned those WAV files to CD), the sound quality on the CD will be MP3 quality.  In the 90s, 128kbps MP3s were pretty standard.  They will sound compressed on the CD.  If you were to rerip those and compress them to MP3 again, the sound quality will be absolutely terrible.

This is the impression I got from some files.

Very basically, V0, V1, V2 refer to the Lame Variable Bitrate Preset used when converting to MP3.  Variable Bitrate means more bits are used for more complex passages and less for less complex passages.  V0 is the highest quality variable bitrate preset, and V9 is the lowest.  You can also rip to Constant Bit Rate, using the same number of bits to compress simple passages as you do to compress complex passages and wasting a lot of space in the process.  Read phred's links for the technical details.

So that means that V2 basically is still good as it is not an indication of a certain bitrate but an indication of the variety this bitrate might have.

Programs like Audiochecker (https://www.freewarefiles.com/Audiochecker-Beta_program_21299.html) and Lossless Audio Checker (http://losslessaudiochecker.com/#downloads) try to guess whether a file is from a lossless (CD / FLAC, etc) source.  In other words, if you rip a CD to wav or flac and put the wav or flac into those programs, it guesses if the source of that file is lossless. It checks how much information is present in certain frequency ranges in the file that should be present in lossless sources but are missing due to compression in MP3 files. There is some debate as to how reliable this method is, but I've found it works reasonably well.

I will give this a try!

[frankz]

Very basically, V0, V1, V2 refer to the Lame Variable Bitrate Preset used when converting to MP3.  Variable Bitrate means more bits are used for more complex passages and less for less complex passages.  V0 is the highest quality variable bitrate preset, and V9 is the lowest.  You can also rip to Constant Bit Rate, using the same number of bits to compress simple passages as you do to compress complex passages and wasting a lot of space in the process.  Read phred's links for the technical details.

So that means that V2 basically is still good as it is not an indication of a certain bitrate but an indication of the variety this bitrate might have.

Yes, V0-V2 are generally considered "Good" for music.  As you get into more compression they become less suitable for music and more suited to spoken word like audiobooks or lectures or talk radio.  One of the links provided earlier should give a general guide as to the average bitrate associated with each VBR setting IIRC.  I can hear the difference between V1 and V2 - most in cymbals and other higher frequency instruments.  I can't reliably hear the difference between V0 and V1 - sometimes, very very rarely.  I rip everything to V0 mostly for my own mental well being.  A lot of what constitutes "sound quality" takes place in your mental process as phred alluded to earlier.

Not that you asked, but as it's information kind of along these lines...

Very basically, lossless compression like FLAC or APE compress the file by rearranging the data in such a way that it can easily be arranged back to its original form with no difference to it at all.  It is like ZIP or RAR.  When you ZIP a document, it's like 1/4 its size, and then when you unzip it back to a document its exactly the same as it was.  No loss of data. When you compress a FLAC, FLAC.exe rearranged the data more efficiently than it was originally as a WAV and then, when you play it back, FLAC.exe knows how to put it back to its original form.  You're hearing exactly what the source sounded like.

Lossy compression like mp3 or AAC compress the data by throwing away bits of the audio.  They start with bits that are out of normal human hearing range that you might be able to "sense" when listening to music but not actually hear.  As you step through the more intense levels of lossy compression, more relevant audio is thrown away.  And higher compression methods (smaller files) makes different decisions than lower compression methods (bigger files) do.  Things that V0 might toss, V2 might save because it's throwing out three other things along the way that V0 would have kept.  They're not purely incremental.

This is why it's very bad to take mp3s and recompress them - it's only going to make them worse because different parts of the audio may be thrown away in place of other parts that would have been preserved but are now gone due to the prior compression.  And, this is why taking an mp3 and converting it to wav or flac doesn't add any quality - the audio was already thrown away by the compression. It's not coming back no matter how big you make the file.  It's long gone.

I find it fascinating.  Not many people do.