NeroAAC

From Hydrogenaudio Knowledgebase


Nero AAC Codec

Developer(s) Nero AG
Release information
Initial release {{{released}}}
Stable release 1.5.4.0 (Feb 18. 2010)
Preview release n/a
Compatibility
Operating system Windows, Linux
Additional information
Use Encoder/Decoder
License see site for license
Website Nero AAC Codec

The Nero AAC codec has been made freely available by Nero AG for personal non-commercial and/or technology-evaluation purposes. It is a set of three command-line tools that are used to encode, decode and apply tags to MP4 files. The download contains binaries for both Windows and Linux. It is the same codec that is used in Nero's other, commercial products.

The three command-line tools are:

  • NeroAacEnc
  • NeroAacDec
  • NeroAacTag


This article is still a work in progress

NeroAacEnc

This is the encoder command-line tool. It is currently at version 1.5.4.0 and was last updated Feb 18th, 2010.

Usage

Windows

neroAacEnc.exe [options] -if <input-file> -of <output-file>

Linux:

./neroAacEnc [options] -if <input-file> -of <output-file>

Note: Make sure the binary is executable

Where:

<input-file>
Path to source file to encode.
The file must be in Microsoft WAV format and contain PCM data.
Specify - to encode from stdin.
Note that multiple input files can be specified, they will be encoded together into a single output file with chapter marks indicating source file divisions.
<output-file>
Path to output file to encode to, in MP4 format.

Options:

Quality/bitrate control:

-q <number>
Enables "target quality" mode.
<number> is a floating-point number in 0...1 range. I.e. 0.5 or 0.75, etc. with 1 being the highest quality and thus also having the largest output file size.
-br <number>
Specifies "target bitrate" mode.
<number> is target bitrate in bits per second.
-cbr <number>
Specifies "target bitrate (streaming)" mode.
<number> is target bitrate in bits per second.

When neither of above quality/bitrate options is used, the encoder defaults to equivalent of -q 0.5

Multipass encoding:

-2pass
Enables two-pass encoding mode.
Note that two-pass mode requires a physical file as input, rather than stdin.
-2passperiod <number>
Overrides two-pass encoding bitrate averaging period, in milliseconds.
Specify zero to use least restrictive value possible (default).

Advanced features / troubleshooting:

-lc
Forces use of LC AAC profile (HE features disabled).
-he
Forces use of HE AAC profile (HEv2 features disabled).
-hev2
Forces use of HEv2 AAC profile

Note that the above switches (-lc, -he, -hev2) should not be used. The optimal AAC profile is automatically determined from quality/bitrate settings when no override is specified.

-ignorelength
Ignores length signaled by WAV headers of input file. Useful for certain frontends using stdin.