How Many Mp3s...

[sete]

Hello there.

I've searched for this a lot here and elsewhere on the web, but couldn't find a definite answer.

How many MP3s can I fit into a 1GB disc? And into a formatted regular MD?

I ask this because in one table I found something like 4 1/2 hours worth of music in MP3 format, but that is a lot less than the comparable amount of Atrac-encoded tracks.

If that is correct, how come there's such a big difference?

[The_Stamp]

hmm. you can figure it out using this calculation.

S = disk size, in MB

B = Bit rate, in Kbps

T = Time available, in hours

in this case, for our purposes, we shall use 128kbps mp3 codec.

T = ((S * 1024) / (B/8)) / 3600

18.2 = ((1024*1024)/128)) / 3600

18.2 hours without the data used for system directory listing (i dont know the number right now)

you can use this formula with any bitrate, or any filesize (like, find the time if a file is a certain filesize).

edit: i changed the 132kbps to 128mp3.. because in excel i used 128kbps, and i closed the window

Edited May 2, 2005 by The_Stamp

[bug80]

hmm. you can figure it out using this calculation.

S = disk size, in MB

B = Bit rate, in Kbps

T = Time available, in hours

in this case, for our purposes, we shall use 128kbps mp3 codec.

T = ((S * 1024) / (B/8)) / 3600

18.2 = ((1024*1024)/128)) / 3600

18.2 hours without the data used for system directory listing (i dont know the number right now)

you can use this formula with any bitrate, or any filesize (like, find the time if a file is a certain filesize).

edit: i changed the 132kbps to 128mp3.. because in excel i used 128kbps, and i closed the window

←

Note that 1 kbit is officially equal to 1000 bits and not 1024 bits, unlike bytes.

Someone correct me if I'm wrong.

* EDIT *

The equation than becomes:

T = ((S * 1024 * 1024) / (1000*B/8)) / 3600

Edited May 2, 2005 by bug80

[The_Stamp]

the reason i divide by 8 is because there are 8 bits in one byte. and file storage is usually rated in bytes, not bits.

here are the components to my equation:

First, i make the measurements the same units (I like to deal with bytes, not bits).

(S * 1024) Stepping the megabytes down to kilobytes.

(B/8) Stepping up kilobits to kilobytes

(kilobytes/seconds) = size{in kilobytes}

therefore

(kilobytes / size{in kilobytes}) = seconds

T1 = ((S * 1024) / (B/8))

as for the last part, i am stepping the unit of measurement up to hours from seconds (60*60 = 3600). so the formula becomes

T = (T1) / 3600

T = ((S * 1024) / (B/8)) / 3600

edit: as for the bits in a kilobit thing... google says differently.

http://www.google.ca/search?hl=en&q=bits+in+a+kilobit&meta=

Edited May 2, 2005 by The_Stamp

[bug80]

edit: as for the bits in a kilobit thing... google says differently.

http://www.google.ca/search?hl=en&q=bits+in+a+kilobit&meta=

←

Hm strange. As far as I know there are two different versions for "kilobit":

1) Storage: 1 kilobit = 1024 bits

2) Datarate: 1 kilobit per second = 1000 bits per second

I thought compression formats like MP3 used version 2 (because it actually uses a datarate), but I have to find that out in more detail. Last time I checked, I calculated the size of a MP3 using the bitrate and number of samples and I had to use option 2.

* EDIT *

This is what wikipedia has to say:

Additionally, kilo and mega often have their traditional SI meanings when referring to rates of data transfer. For instance, 56 kilobits per second is 56 000 bits per second, not 57 344 bits per second

Edited May 3, 2005 by bug80

[bobt]

All of them!!

Could be one if it's a really long song, or many if they are short songs at low bitrates.

It's a compromise, quality, listening environment, etc.

Bob

[bug80]

By the way, there's already been a topic about how many hours will fit on a MD: click here.

So, if you know the length of your MP3's in hours & minutes, you can calculate it from there.

[hobgoblin]

yes originaly a kilobyte was equal to 1024 byte, but as kilo is normaly equal 1000 they introduced some time ago the expression kibi (i think it was that) to cover their asses when storage media had their space calculated in 1000 rather then 1024. even more funny is that a os like say windows calculate in 1024 but lable it kilobyte rather then kibibyte...

[Guest NRen2k5]

yes originaly a kilobyte was equal to 1024 byte, but as kilo is normaly equal 1000 they introduced some time ago the expression kibi (i think it was that) to cover their asses when storage media had their space calculated in 1000 rather then 1024. even more funny is that a os like say windows calculate in 1024 but lable it kilobyte rather then kibibyte...

←

Yes, kibi is such a joke. It is supposedly now the "correct" suffix for a quantity of 1024, but nobody and I mean nobody uses it!

[Wedge]

kibibyte. What a cute word.

[though]

i think i have 175 on mine.

[Damage]

You know, all of these would've been answered quite easily by saying something to the order of:

About the same as other 1GB MP3 players

-or-

About the same as 1GB iPod Shuffle

-or-

About 30% more than your average single MP3/CD.

[The_Stamp]

actually, its 42% more space than a CD youd think that its 30, because its 300 megs down from a gig, which makes a CD 30% less than a hi-md. but a hi-md has 42% more space than a CD

btw, i have 132 kbps songs for assorted songs, 64kbps for full albums, 256 kbps for special unique flagship songs, and 64kbps radio broadcasts (i record an hour's worth in 192kbps, then bring it to 64kbps atrac3plus for my hi-md.) time on my disk so far: 17 hours between 185 songs, with another 273 megs left . ALL THAT ON ONE DISK. NOW THATS DISK MANAGEMENT! (btw, i use a nh900 )

Edited May 4, 2005 by The_Stamp

[Damage]

To add to things:

Various rates (128-192kbps):

231 tracks, 11 hours and 16 minutes on a 1GB disc almost full (about 11:00 remaining).