MP3 help

[nymph4]

I have two WAV File that are the same but one is 44.1 kHz Stereo at 16 Bit and the other is 22050 kHz Mono at 8. Bit

I put them both through MP3 Encoding at 98 kbps.

They both come out  638 kB in Size??

I don't understand this because I thought the WAV File that is 22050 kHz Mono at 8. Bit  already is a por quality so wen I put it throu the MP3 Encoding it should be even Smaller then the other.

Please explane???

[Cityscape]

I'm not quite sure that I understand what you mean.

638 kB sounds about right depending on the length of the track.

[nymph4]

What I meen is   one file starts out very High quality  44.1 kHz 16 Bit  Stereo  this is  CD  quality

The other file is 22050 kHz  8. Bit  Mono  ver pory quality.

Wen the both of them are encoded  the one that is very low quality to start with will cokme out smaller  RIGHT

[Cityscape]

Not necessarily. What is the durations of the 2 files?

[nymph4]

60 Sec.   why??

[rthompson80819]

The other file is 22050 kHz  8. Bit  Mono  ver pory quality.

I think you either are missing a decimal point in there somewhere, or meant Hz.

[nymph4]

yes I ment HZ

Both are  HZ  but one is very low  22050 Hz

[Salmon Trout]

mp3 size= channels x (bitrate x duration)

[Geek-9pm]

mp3 size= channels x (bitrate x duration)

The relationship expressed above  is valid. There are more factors involved that determine the exact size.

[Salmon Trout]

The relationship expressed above  is valid. There are more factors involved that determine the exact size.

I should have said that was for cbr (constant bit rate) mp3 files. In fact the bitrate is normally quoted for 2 channels together so a 128 kilobit/sec mp3 lasting 60 seconds will have a size of (60 x 128000) / 8 bytes

[Geek-9pm]

I wish I could contribute more to this thread. The dentist had sooth pullout  today  un eye  can hardly talk. Anyway, here goos.
Digital speech compression has fascinated me for years, long before the MP3 method became popular. For years the telephone company has used digital compression to reduce the bandwidth required on their long distance systems. Thus they could carry more conversations without expanding their equipment.
The modern MP3 format serves a similar purpose. Moderate compression in the MP3 format sounds good even on music. More intense compression tends to make this sound rather rough and produces many artifacts. An artifact is a strange sound that is not directly connected to the original sound in the musical or harmonic sense that our years are accustomed to.
Here is a very good book that you can read. Well, you can read the first few pages, which is enough to let you know that MP3 is much more sophisticated than the WA V.
The cancel below is recommended reading.
Understanding MP3: syntax, semantics, mathematics, and algorithms - Google Books Result

[BC_Programmer]

I wish I could contribute more to this thread. The dentist had sooth pullout  today  un eye  can hardly talk. Anyway, here goos.
Digital speech compression has fascinated me for years, long before the MP3 method became popular. For years the telephone company has used digital compression to reduce the bandwidth required on their long distance systems. Thus they could carry more conversations without expanding their equipment.

It wasn't really "compression" since all they did was strip out higher and lower frequencies.

Well, you can read the first few pages, which is enough to let you know that MP3 is much more sophisticated than the WA V.

a WAV file can be compressed via Mpeg layer-3.

FLAC is much better, overall.

[Geek-9pm]

It wasn't really "compression" since all they did was strip out higher and lower frequencies.

Digital compression. Can't you read?

How voice compression saves bandwidth
Gary Audin
The Public Switched Telephone Network (PSTN) started with the transmission of analog speech. This worked well for decades until the areas under city streets became saturated with copper cables, one copper pair per call. Starting in the 1950s, AT&T Bell Labs developed a technique to carry more voice calls over copper wire. They developed digitized voice technology through which 24 digital calls can be carried on two pairs of copper wire, thereby increasing the carrying capacity of the cables twelvefold. The voice is digitized into streams of 64,000 bps per call. The technology is called a T1 circuit and the bandwidth for the 24 calls is 1.544 Mbps. This worked well for domestic connections. The T1 technology then became the mechanism for long-distance domestic transmission.

Most of the early voice compression technologies were designed for undersea cables, where bandwidth was limited an...

The above shows that digital voice was in use before you were born. My reference is to the compression that is used after the voice has been digitized. Most often needed for long distance circuits. This research by Bell Labs was the precursor of other compressed digital audio formats that came later on.

[nymph4]

thanks

[BC_Programmer]

Digital compression. Can't you read?

Yes. MP3 does the same thing, and I'm fairly certain that the input is a digitized waveform. In fact, a good chunk of the waveform that needs to be compressed is stripped off by removing the sounds above and below certain wavelengths.

The above shows that digital voice was in use before you were born. My reference is to the compression that is used after the voice has been digitized. Most often needed for long distance circuits. This research by Bell Labs was the precursor of other compressed digital audio formats that came later on.

First: I'm tired of having to google for your references. you can't just paste in a blurb of text from god knows where and take it as fact. I did find this http://searchunifiedcommunications.techtarget.com/tip/0,289483,sid186_gci1239944,00.html

In either case, all it proves is that voice is digitized. hardly notable. the "compression" is simply the stripping off of higher and lower frequencies, leaving a comparatively narrow band (which is why hold music sounds so awful). This means that "space" that was used for sending the higher and lower frequencies  can be used for more calls.

They didn't actually implement a compression algorithm. If they did your ten second google would have surely found that.