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Tuesday, 3 November 2009

The M Bizzle Rough Guide to Converting MP3's

(Links to Wikipedia and other relevant articles are included throughout. Please note also that this is a first draft of an article about what can often be a highly debated topic so tweaking, editing and revised opinions on the information contained within are to be expected...)


Highest Quality Data Source -

- The Actual CD -
The original source of the data is on the CD itself...most music nowadays is recorded digitally in .WAV format and added to the CD in this format. There is of course mastering etc. before it reaches the CD but that is another story for another day.


Lossless Formats (formats which are EQUAL to the data on the CD
...)

- FLAC -
This is a lossless format. That means that it takes the EXACT data from the CD without losing any data. Because of this you will notice the size of the albums to be much bigger (300-500mb) which is nearer* to the size it would be on an audio CD (which can store 700mb of data).

*They are always smaller because FLAC files are kind of like Winzip for audio; they can make the files smaller (sometimes by more than 50%) but without losing any data (how this works is too complicated to explain and again is another story for another day)...


Pro's

Having a album in FLAC format is equivalent to owning the actual physical CD. There is NO loss in sound quality whatsoever. Converting to MP3 from FLAC is the same as converting from the CD itself.


Cons

FLAC files will not play thru xBox, Media Player, iTunes or on an iPod. Therefore you will probably have to convert them to MP3. They will play in VLC media player, however unless you have a good sound card and a high end stereo system connected to your PC you will not be able to hear the true quality of FLAC. In other words there is no real need to have music files at this quality unless you have a system that will give playback at this quality.

- Apple Lossless -
Apple Lossless files are the Apple equivalent to FLAC. Again there is absolutely NO loss of quality compared to the original source data on the CD.

Pro's
This format WILL play in Apple iTunes or on an iPod.

Cons
Again, unless you have a high end system connected to your laptop you wont notice a difference. If you just play music thru standard speakers on a mid-price range laptop for example, you wouldn't notice any difference between an MP3 and a Lossless file. In fact the MP3 would be a better option because it would take up much less room on your laptop.

The other con about the Lossless format is that the playback on iPods themselves is not actually that great. I don't know about the highest priced iPods but the iPod Nano playback is definitely not good enough to hear the true quality of a Lossless file. The headphones aren't good enough either. So basically if you fill your iPod Nano with Lossless files you won't be able to store half as many albums as you could in MP3 and not only that but you won't be able to hear any difference in the quality compared to a decent MP3 version anyway.

Lossy Formats...

- MP3s -
First of all a little about MP3's. An MP3 is basically a compressed version of an original sound file. However, unlike the Lossless format of FLAC, MP3 uses Lossy Compression. The purpose of compressing it is to make it smaller in size and therefore more portable and economical.

For example, if you were in a recording studio recording a song, you would record it onto the studio PC as a .WAV file. By doing this you are basically recording the sounds that are being fed into the microphones exactly as they are. Again it is important to understand that an MP3 is a compressed version of a raw sound file such as .WAV

If the song was 3 mins long, the .WAV file you record to the hard drive might be about 70mb in size (this is just an example figure, it would depend on how much instrumentation you are recording etc.)

As you probably know, a 3 minute MP3 file would probably only be about 2-5mb (depending on the quality of the MP3 bitrate which we will talk about in a moment). 2-5mb is obviously a lot more practical for MP3 players etc. because you could fit about 200 MP3s on a 1GB MP3 player compared to about 15 .WAV's on the same size player.

So how do you compress a 70mb sound file down into a 3mb sound file?

There is only one way and that is to DISCARD some of the information. Now that doesn't mean that the MP3 format of the song will have no drum track or no guitar solo in the middle LOL. In reality the majority of these are high and low end frequencies that are out of range to the human ear so you won't even notice unless you have super human hearing.

However...there are many different types of MP3 quality that you WOULD be able to notice the difference with:

Bit Rates

- MP3 @ 64kbps -
This is about the lowest rate you can create an MP3 at. It is acceptable for human speech only (a podcast or an audio book etc) but for music it is absolutely fucking AWFUL. It will sound like the song has no EQ and the better the system you play it on the more you will notice how tinny and hissy and shitty it sounds.

- MP3 @ 128kpbs -
This is ok for shitty laptop speakers and MP3 players but on a decent system it will sound sub par. You would definitely notice if you played the same music from the original CD on the same system.

- MP3 @ 192kbps -
This is what I would consider an acceptable MP3. It is listed as "CD Quality" on a lot of converters (iTunes etc.) and to be honest it is acceptable to most people with average hearing and average sound player equipment. If you are just a casual music listener and you don't concentrate on things like the EQ of a snare drum or the clarity of bass etc. then this is usually sufficient. MP3s at this bitrate are usually a nice small size and perfect for people who want quantity rather than quality of music on their systems. Again tho like I said, this quality is quite acceptable and calling it otherwise is just snobbery :)

- MP3 @ 256kbps -
This is getting closer to the quality of a FLAC or LOSSLESS file. At this bit rate, very little information is discarded. 256 kbps MP3's will be a bit bigger compared to the 192 kbps versions for this very reason.

- MP3 @ 320kbps -
This is the closest you can get to the quality of a FLAC file but in MP3 format. Only the most non-essential information is discarded when converting into MP3 and therefore the file retains as much of the original information as possible. As a result, these will be the biggest sized MP3 files.

*** To let you judge for yourself, I will take a FLAC music file soon and convert it into each of these formats, then I will post a link to every version including the original FLAC so that you can download and listen to each one to see if you can notice any difference on whatever your system of choice is.

And now just to make things MORE confusing:

There are two different methods for converting a file into MP3: CBR or VBR. There is a third called ABR but I'm going to leave that one out for the moment.

CBR
CBR is CONSTANT BIT RATE. This means that if you convert to MP3 at 320kbps CBR then the MP3 will be 320kbps for the ENTIRE song. Every second of the song will be at 320kbps.

Now here is the thing...does every single second of the song NEED to be at 320kbps? Some parts of it might definitely need to be, and some songs in their entirity might need to be. But if for example there is silence in the song, how could you possibly notice the difference between silence at 320kbps or silence at 192kbps. You are listening to SILENCE!!

So whereas 320kbps is definitely the ideal bit rate for an MP3, the fact is that not every song (e.g. songs with minimal instrumentation and sound) needs to be at 320kbps. As I mentioned before, the 320kbps MP3 files are the largest in size, but if the song doesn't need to 320kbps for every single second of the song, then you could be creating an MP3 which is larger in size than it needs to be. The sound quality will be perfect of course, but like I said it may make the file larger than it needs to be. Unless you do need to listen to silence @ 320kbps of course...

VBR
VBR is VARIABLE BIT RATE. This is self explanatory; the bit rate varies based on the how much it can be compressed without compromising data.

There are 9 different quality settings for VBR:

-V 9 - POOR - Estimated Bit Rate: 70kbps
-V 8 - POOR - Estimated Bit Rate: 80kbps
-V 7 - POOR - Estimated Bit Rate: 100kbps
-V 6 - POOR - Estimated Bit Rate: 120kbps
-V 5 - POOR - Estimated Bit Rate: 130kbps
-V 4 - MEDIUM - Estimated Bit Rate: 100kbps
-V 3 - MEDIUM - Estimated Bit Rate: 170kbps
-V 2 - STANDARD - Estimated Bit Rate: 190kbps
-V 1 - HIGH - Estimated Bit Rate: 220kbps
-V 0 - EXTREME - Estimated Bit Rate: 240kbps

-V 0 would be the ideal setting to get the best possible quality MP3 but at a smaller size than a 320 CBR. In other words, if it NEEDS to be 320kbps then it will be but if it can be less then it will be.

Example

Converting "The Long & Winding Road" from FLAC to MP3
[FLAC filesize is 19.3 MB]

1. FLAC to MP3 using 320kbps CBR

Result: The MP3 file is 8.16 MB in size with a bit rate of 320kbps

2. FLAC to MP3 using -V 0 VBR

Result: The MP3 file is 5.44 MB in size with a bit rate of 213kbps

So as you can see, you could rip the track at 320kbps if you want absolutely consistent high quality, but the song only needs to be at 213kbps and as a result it is about 3MB smaller. Also, it is HIGHLY UNLIKELY that you would be able to hear any difference in the two versions with 90% of music systems and 90% of human ears.

How do I convert my MP3's?
So my own personal preference is to either download albums in FLAC format or convert them to FLAC from my own CD collection and then convert them to MP3 in -V 0 VBR format. This means my MP3 collection has probably the best balance between having the highest possible quality of sound with the smallest possible size of MP3 (without compromising quality to achieve that small size)

However, the majority of my MP3 collection (20,000+ songs) is NOT at this quality and won't be until I like the album enough and listen to it enough to go and get a better quality version. A lot of my collection is reference material or things I listen to purely to check out a certain genre of music and maybe learn something from. The stuff that I listen to a lot is all I am interested in hearing at this level of quality because I know the music so well that I would hear the difference on a decent system*

*I store my MP3's on a laptop which is wirelessly connected to the XBox360 using Windows Media Player Sharing. The xBox is connected to a Logitech 5.1 surround system using a fibre optical digital cable (TOSLINK). You NEED to be using this sort of equipment and cabling to be able to hear the quality of higher bit rate MP3's, if you are using a standard AUX audio cable (left and right red/white cables) then you won't hear the difference in quality (maybe between a 64kbps and a 220kbps or something extreme like that).


Conclusion

As long as the MP3 is at LEAST 192kbps it will sound fine on pretty much any system.

For lower quality systems you could probably even go as low as 128kbps but NO LOWER with music.

If you have a good sound system and want your MP3's to be as close to the quality of sound that you would get on a CD then you should convert either the CD itself of the FLAC version into MP3 using -V 0 VBR. You could also use 320kbps CBR but as I mentioned before you will have larger sized MP3 files when they might not need to be. (Note: The best program to use for converting to MP3 is dBpoweramp)

If you want to make a virtual backup of your CD collection then you should convert them to FLAC format and store them on an external hard drive. That way, if anything should happen to your CD collection in the future, you will have EXACT virtual replicas of them on your hard drive and you can then use this as your root source for converting to MP3. Because of the huge size of FLAC files, I would only use them in this scenario. If I am just looking for one album online then I will download it in FLAC format, convert it to MP3 and then delete the original FLAC version to save space on the laptop hard drive. The reason I download it in FLAC format instead of just looking for the MP3 version is because most MP3 versions are ripped badly using poor converters. There is an online group called DarksideRG which have strict quality standards for ripping so if I saw an album with DarksideRG in the filename or details I would trust it but the majority of everything else out there is sub standard.

There are a couple of other things related to creating and maintaining your MP3 library which I will post articles about soon:

ID3 Meta Data - The information embedded into the MP3 (Song Name, Track Number, Artist etc.) that displays in your media player of digital screen on your MP3 player.

C2 Error Correction - To avoid hissing and popping transfer and to rip scratched CD's.


Useful Links
Hydrogen Audio - The be all and end all of audio info
stevehoffman.tv - The meeting place for audiophiles
What the hell is an "audiophile"?
7 Facts Audiophiles Need to Know About Digital Music
The World's 15 Sexiest Speakers Put Your Girlfriend to Shame
VBR vs. CBR
ABR (left out of article)
How MP3 works


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