more on .mp3

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The Great Watbol!
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more on .mp3

Post by The Great Watbol! »

I would like to know the difference between 44100 192Kbs Stereo.mp3
and 44100 ACM 192Kbs Stereo.mp3¿?
Is the ACM like PCM, (raw-uncompressed)¿?
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DougDbug
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Post by DougDbug »

ACM = Audio Compression Manager. It's a protocol that dictates how a CODEC interacts with Windows.

Anything with a bitrate of 192kbps is compressed. PCM at 44,100, 16-bit stereo has a bitrate of 1411kbps. FLAC (lossless compression) of the same format has a bitrate around 800kbps.
GoldWave wrote:MPEG attributes with the letters "ACM" use the MP3 encoder included with Windows Media Player (through the Windows Audio Compression Manager). Usually that is the Fraunhofer encoder, which is the one designed by the people that created the MP3 format. It does not always work reliably within GoldWave, but it gives very good quality at lower bitrates.

MPEG attributes without the "ACM" letters use the LAME encoder, which is the most widely used free encoder. It gives the best quality at higher bitrates.

Chris

The Great Watbol!
Posts: 34
Joined: Mon Sep 22, 2008 5:07 am
Location: In the back of your mind(s)

...

Post by The Great Watbol! »

So, ACM uses windows compression, and other use LAME one.

Once again, You've satisfied my Curiosity.
This gives me joy in learning something new.
:shock:
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DewDude420
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Post by DewDude420 »

ACM merely runs through windows compression manager to access the codec and lame goes directly yo a .dll. That's the only difference.

ACM codecs are generally more difficult to code and you lose a lot of flexability options.

Saying one uses windows compression and one uses lame is half right. Imagine this...this is going to be a bad analogy...

You want to compress to mp3...you got two options....acm mp3 and lame mp3. When you select LAME, goldwave basically goes to lame and says "I need this in mp3 at this bitrate", LAME, being an encoder, says ok...does the work, spits out a file.

The ACM codec works like this.....goldwave tells windows "I need this in mp3 using this bitrate", the ACM manager then goes through it's list of mp3 encoders, encodes it, spits it out.

The only difference is one is going to be whatever codec windows has and one will be lame....that is not to say the ACM codec can't be Lame....if you had the lame acm codec. Most of the ACM codecs I've seen that aren't lame are pretty crappy.

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