# How can i convert MPEG-4 Audio File to MP3?



## SpyKiller112 (Aug 24, 2004)

My first question is basicly what the title says.. How do i convert a MP4 to an MP3?

My second question is, what is the average size for a song? 
Does 2,3,4 MB sound like alot?

Because i can only hold on average 28 songs on my RCA Lyra Mp3 player with 128MB virtual memory. 2 other people who have the same one say they can get 60 songs on there w/o a card for extra memory.


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## Moby (Mar 19, 2002)

The free Itunes player will convert MP4 to MP3, although, funnily enough it won't convert protected mp4's downloaded from Itunes. Where did you get your MP4's from?
The size of a song (mp3) depends entirely on it's length and the bitrate at which it is encoded. You can choose the bitrate but the length of the song is obviously out of your control. The lower the bitrate, the lower the quality. Some say 128kb is CD quality - I doubt it but it's good enough for a 128mb mp3 player where size of songs is important due to the lack of space. Go to 192kb, it's better, 256kb better again. I can't tell the difference between 256kb and 320kb (maybe I need a better stereo )
To put it into very rough average figures for you a 3 minute song, converted to mp3, in different bitrates will be

128kb - 3mb
192kb - 4.3mb
256kb - 5.7mb
320kb - 7.2mb

That can only be a rough estimate because every song is different with different things going on in each song.

Mp3pro is another type of mp3 with a bitrate of 80kb - it's supposed to be the same quality as a 128kb with no quality loss. Not sure about that, you'll have to let your own ears be the judge. Nero has a plugin for mp3pro (not free) You'll get down to 2mb or below at that bitrate.

If your player plays .wma files then they are generally accepted to be a better quality at lower bitrates.
Windows media player rips to .wma files and you'll save space by using them.

In windows media player, go to tools, options, rip music. Play with the slider there at different bitrates to give you an idea of how much space a full CD takes up in mp3 and .wma formats.

And the last thing - every time you re-encode a track you'll loose some quality as mp3 is a 'lossy' format. The way to make and keep an mp3 at a decent quality is to rip it once, from the audio CD, at the bitrate you require (the higher the bitrate the better the quality) and leave it alone to play to your heart's content. If you want it at a different bitrate, rip from original CD again. If you want to re-encode music that is already in mp3 format, then you're already on the quality downward spiral.


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## Couriant (Mar 26, 2002)

Just to reliterate what moby has said, the lower the bitrate the lower the quality the music is. Think going from Stereo to Mono with crackling. As for the Mb, it depends on the bitrate and the length of a song. A 2 1/2 minute song on 128Mb is about 3Mb, which is about 40 songs. But nowadays the bitrate used is 192 or more. 


spykiller said:


> 2 other people who have the same one say they can get 60 songs on there w/o a card for extra memory.


Ethier:
1) They must have a larger capacity and they don't know it
2) They have low bitrate music
3) They are bs'ing you


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## SpyKiller112 (Aug 24, 2004)

So can i change the bit rate of a song? And if so should i change it to 128MB that seems to be the average, right?

Edit: How do you convert the MP4 to an MP3 on Itunes? The only thing i see is "convert selection to AAC"


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## Moby (Mar 19, 2002)

> The only thing i see is "convert selection to AAC


That suggests that your mp4's are licence protected. As I asked before, where did you get them from?


> So can i change the bit rate of a song? And if so should i change it to 128MB that seems to be the average, right?


Yes you can. What bitrate are they at the moment? If you re-encode mp3's you'll loose quality, not only by reducing the bitrate, but by the act of re-encoding them. The bitrate is up to you, you have the measurements. 128kb will sound good enough in your mp3 player.


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## Couriant (Mar 26, 2002)

128kbps was the norm, now it's 192kbps. 128kbps is standard quality. I would go for that since MP3s take out sounds that are not 'hearable' to the human ear.


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## daurnimator (Nov 20, 2004)

Try this program:
http://www.dbpoweramp.com/dmc.htm

it lets you convert music and modify bitrates easily.

Many formats are supproted but I always choose mp3 for combatibility issues.


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## Couriant (Mar 26, 2002)

hmm does anyone know what file type are the iTunes purchased music is?

For the iTunes, I'm thinking the same thing as Moby. If they are the files from iTunes, then I'm guessing you can only do ACC, since iTunes uses that as the default. And if they are yours you should be able to download them into a player that is supported by iTunes.


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## SpyKiller112 (Aug 24, 2004)

i think i found a way.. if they are not protected. You go change the import options to mp3's. it is set on ACC by default.



> As I asked before, where did you get them from?


I burned them from CD's



> What bitrate are they at the moment?


I have them all. I have: 32,48,56,64,80,96,112,128,160,192,224,256,320

MP4's do not have a bit rate


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## Moby (Mar 19, 2002)

Yes you have to tell it you want mp3's. They will not be protected if you ripped them from a CD. My question about bitrate was refering to your exisiting mp3's by the way, 'cause you asked - 
"So can i change the bit rate of a song?"
And seeing as mp4's don't have bitrates . . . . .


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## SpyKiller112 (Aug 24, 2004)

i may want to lower the bitrate on the mp3's that have 320 for a bitrate, or maybe the 256's too. So when you said,"If you re-encode mp3's you'll loose quality" does that mean my mp3's of 320 bitrate will go to a 128?

i want to get the most space in my MP3 player as i possibly can without sacraficing the quality of the music. So if changing the bitrate of a song is going to lower its quality, then ill just leave everything alone.


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## Moby (Mar 19, 2002)

> i may want to lower the bitrate on the mp3's that have 320 for a bitrate, or maybe the 256's too. So when you said,"If you re-encode mp3's you'll loose quality" does that mean my mp3's of 320 bitrate will go to a 128?


They will go to whatever you set them to go to. You have to understand 2 things.
1 - The act of re-encoding an MP3 looses quality. If you take a 320kb mp3 and "re-encode" it to the same 320kb (pointless I know but bear with me) it will loose quality during the process as mp3 is a lossy format.
2 - Lowering the bitrate of an mp3 looses quality regardless of the above

So if you re-encode a 320kb mp3 to 128, not only will you loose quality in the re-encoding process, but you'll loose quality in the reduction of bitrate. It's not good.


> i want to get the most space in my MP3 player as i possibly can without sacraficing the quality of the music.


You can't have quality and more space - something has to give.

What you should do is copy your 320kb mp3's somewhere - re-encode the copies to 128kb and see how they sound. That way your originals are still intact.


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