how does MP3 really work?

[techno]

yeh i know, this is a stupid question but really, how does MP3 work?

i need to know more in depth for a report I am doing. so far I have basically said that it's compression and stuff, done a diagram/chart showing that the higher bitrate = bigger file size, sometimes quality CAN be improved, depending on the source.

it cuts the high frequencies humans can't here (this will go in the how psycho acoustics of mp3's)

anything else?

how in general does MP3 work?

Thanks

Techno

[SKD_Tech]

What MP3 codec does, is that it gets rid of parts of audio that you and I cannot hear. Our human ears are quite limited in that after hearing something loud, you can't hear quiet sound for short period of time. MP3 codec calculates and deletes that part. This is how MP3 achieves its great compression ratio without the apparent quality loss. Our human ears are quite limited in that after hearing something loud, you can't hear quiet sound for short period of time. MP3 codec calculates and deletes that part

Want it more in depth?


The Fraunhofer IIS labs in Germany created the MPEG 1 layer 3 codec. Their compression algorithm is based on perceptual encoding. Researchers found that there are certain harmonics in audio signals that humans cannot perceive, as well as harmonics that obscure the presence of other frequencies. An MPEG encoder reads an audio file and determines which harmonics are perceptible and imperceptible. This perceptually based exclusion process is similar to the "lossy" compression used in MiniDisk systems, and results in far greater sonic accuracy than compression through lowering the sample rate. Encoding in MP3 format allows the user to select resultant quality in terms of kilobytes per second (kbps). This measurement refers to how many bytes of data will be analyzed per second. The higher the kbps, the larger the file size and the more accurate the sound quality.

I found all this by a simple google search

[techno]

thanks MUCH appreciated

kisses lol

[SKD_Tech]

Originally posted by techno
kisses lol

Umm I don't think I am going to comment on that.

But as for searching no thanks is needed all it took was some keystrokes and 90 seconds

[techno]

lol thanks

i tried searching but my keywords may not be good enough :roll eyes:

[Enchanter]

From my limited reading, MP3 works by removing parts of the audio that the human ear supposedly cannot hear. The effectiveness will vary with different people with different sensitivities, awareness of what to look out for and ultimately the gears they use to reproduce the sound. I used to think 128kbps was enough, but now I cannot even stand listening to anything lower than 192kbps (even this cannot compete with lossless).

The high frequency sound removal is a part of that algorithm. FhG is known for its 16KHz low-pass filtering (which makes it totally unsuitable for musics that frequently reach beyond this frequency value, like Classical and Jazz). LAME solves this problem by introducing configurable low-pass filter (FhG's is fixed at 16KHz).

You probably will need to look up on the net for more specific information on how MP3s work, rather than asking the question in a forum where most people are more concerned with movies. Best of luck.

[techno]

thanks technically it is concerned about movies no sound = no enjoyment in movies hehehe

[Enchanter]

Originally posted by SKD_Tech
Our human ears are quite limited in that after hearing something loud, you can't hear quiet sound for short period of time. MP3 codec calculates and deletes that part

I did not know the MP3 algorithm does that.

What I know, though, is that many multimedia speakers used in computers are incapable of reproducing loud sounds while maintaining quiet passages (so you can hear both extremes). Decent audio equipents can do much better at this. Perhaps this is the reason why the MP3 has such algorithm built in, considering that MP3 will be used mainly with computers.

[SKD_Tech]

To tell you the truth I barely understand anything that I posted but I knew that it would help out Techno so I posted it.

[techno]

lol

thanks and it did.

i hope i pass this report, I really need to, the last coursework was hard and i got 59%! i don't think anyone got more than 65%

i hope i pass...

[SKD_Tech]

Well I barely passed Math with a booming 69! that is the lowest D possible! lol oh well I am going to grip down on my grades this last semester though!

[techno]

hehe, i'm sure u will do fine.

had an assessment on monday for networking, got 60%....passed...not good enough for myself, then databases, i got 20/25 although it was meant to be a group work but no one done anything apart from me!

hmm....i just hope i pass all this, including the upcoming assessments, I WANT TO PASS!! I should know more than the class hehe, im Tech

[SKD_Tech]

check your PM techno so we don't spam up the board