Nero's Free MPEG-4 AAC/AAC+ encoder 'quick start' instructions

This page gives some 'quick start' instructions for people that want to try out Nero's free MPEG-4 AAC/AAC+ encoder, which is (very likely to be) the best MPEG-4 AAC/AAC+ encoder at present.

AAC+

I frequently mention the AAC+ audio codec on the home page of this website in news articles, but AAC+ is actually a company's (Coding Technologies) brand name for the HE-AAC (High Efficiency Advanced Audio Coding) audio codec, which is an MPEG-4 audio codec.

AAC+ uses the standard AAC codec (LC-AAC) to encode the bottom half of the audio spectrum, and a technology called Spectral Band Replication (SBR -- which was invented by Coding Technologies) is used to encode the top half of the audio spectrum very efficiently (i.e. with a very low bit rate -- around 3 - 5 kbps).

AAC+ is currently the most efficient audio codec in existence, so if you want to see how it performs, choose a bit rate level between around 48 - 80 kbps or a quality level of around 0.2 - 0.3 or force the encoder to use HE-AAC by using the -he switch as detailed below.

 

Download & Install

Download Nero's free MPEG-4 AAC/AAC+ encoder, and Exact Audio Copy (EAC).

Install EAC.

 

Setup EAC

Once installed, click the following:

EAC > Compression Options > External Compression tab 

Set the options as in the following figure: 

You can also use .mp4 for the file extension.

In the 'Program, including path, used for compression' edit box, Browse to where you've put the Nero AAC encoder:

  • If you're using an Intel CPU that supports SSE2 then select neroAacEnc_SSE2.exe,
  • otherewise select neroAacEnc.exe

Command Line Options

In the 'Additional command line options' edit box enter the bit rate or quality setting you want to use:

  • [bit rate or quality setting] -if %s -of %d

For guidance of what bit rate or quality setting to use, read this thread on Hydrogen Audio:

http://www.hydrogenaudio.org/forums/index.php?showtopic=44310

Also look at the readme.txt file that will be in the same directory as the neroAacEnc.exe file to see all the other options.

 

Bit Rate Mode Switch Example
VBR - variable bit rate (recommended) -q -q 0.5
ABR - average bit rate -br -br 128000
CBR - constant bit rate -cbr -cbr 128000

 

The following table shows the approximate relationship between quality values (-q) and the variable bit rate level:

Approximate Variable Bit Rate
kbps		 Quality (-q) value
15 0.05
32 0.15
63 0.25
99 0.35
146 0.45
197 0.55
248 0.65
299 0.75
350 0.85
401 0.95

 

The encoder will automatically choose which is the appropriate AAC profile to use based on the bit rate level chosen (or what bit rate the -q value you've chosen relates to), as follows (this may change over time):

AAC Profile Full name of profile Bit Rate Range
kbps
LC-AAC Low Complexity (normal AAC) >= 85 kbps
HE-AAC High Efficiency AAC < 85 kbps
HE-AAC v2 High Efficiency AAC version 2 < 40 kbps

 

You can also force the encoder to encode using a certain AAC profile:

AAC Profile Switch
LC-AAC (normal AAC) -lc
HE-AAC -he
HE-AAC v2 -hev2

 

Examples

If you want to encode to a quality level of 0.5 using variable bit rate mode, use the following:

  • -q 0.5 -if %s -of %d

or if you want to encode with an average bit rate level of 128 kbps, use the following:

  • -br 128000 -if %s -of %d

or if you want to encode with a constant bit rate level of 88 kbps using the HE-AAC profile, use the following:

  • -cbr 88000 -he -if %s -of %d

 

Encode WAV files

Click the following:

Tools > Compress WAVs > browse to and select the WAV files you want to compress > OK > select destination directory > OK

 

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