Nero AAC: Difference between revisions

Revision as of 12:30, 6 July 2006

A commercial implementation of both LC AAC and HE AAC, Nero AAC is produced by Nero AG as part of their Nero Digital line of products. It is generally precieved to have the highest quality VBR LC AAC implementation (although QuickTime bests it in CBR mode at 128kbps). The codec can also create HEv1/v2 AAC streams for extremely low bitrates and supports multi-channel surround sound encoding. As of May 2006, Nero AAC is availble for free as a commandline tool called "Nero Digital Audio".

Command Line Options

Usage

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

<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.

<output-file>: Path to output file to encode to, in MP4 format.

Quality/Bitrate Control

-q <number>: Enables "target quality" mode. <number> is floating-point number between 1 and 10.

-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 none 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 more 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; optimal AAC profile is automatically determined from quality/bitrate settings when no override is specified.

-hinttrack: Generates an RTP hint track in output MP4 file.

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

External References

Nero Digital PDF

Nero Digital Website.

@@ Line 1: / Line 1: @@
-A commercial implementation of both LC AAC and HE AAC, Nero AAC is distributed with Nero 6 which incorporates
+A commercial implementation of both LC AAC and HE AAC, Nero AAC is produced by Nero AG as part of their Nero Digital line of products. It is generally precieved to have the highest quality [[VBR]] LC AAC implementation (although QuickTime bests it in [[CBR]] mode at 128kbps). The codec can also create HEv1/v2 AAC streams for extremely low bitrates and supports multi-channel surround sound encoding. As of May 2006, Nero AAC is availble for free as a commandline tool called "Nero Digital Audio".
-Nero Digital. Generally accepted to have the highest quality [[VBR]] LC AAC implementation (although QuickTime beat
-it in CBR at 128kbps). The codec also features the HE AAC standard for extremely low bitrates. The codec also allows
-for multi-channel surround sound encoding. Unfortunately, unlike iTunes, it's not freeware, and requires the acquisition
-of the entire Nero 6 suite for usage of the AAC encoder alone.
-=Recomended Nero AAC Presets=
+==Command Line Options==
-NOTE: Once a preset has been selected, the "Encoding Quality" option should be changed to the "Fast" mode.  Despite the name implying worse quality then high, a test undertaken by guruboolez shows that the "Fast" mode offers significant quality advantages over the "High" (see the test [http://www.hydrogenaudio.org/forums/index.php?showtopic=29924 here]).  In the forthcoming release of Nero AAC 3.0 (or a release soon afterwards), the "Fast" mode will become the default and the high quality mode will be removed.
+===Usage===
+neroAacEnc.exe [options] -if <input-file> -of <output-file>
-==High Quality==
+<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.
-: - VBR/Stereo - Streaming, 100-120 Kb/s (LC AAC) / Actual bitrate ~150kbps
+<output-file>: Path to output file to encode to, in MP4 format.
-==Portable==
+===Quality/Bitrate Control===
-: - VBR/Stereo - Internet, 90-100 Kb/s (LC AAC) / Actual bitrate ~128kbps
+'''-q <number>''':
+Enables "target quality" mode.  <number> is floating-point number between 1 and 10.
-==Small Filesize==
+'''-br <number>''':
+Specifies "target bitrate" mode.  <number> is target bitrate in bits per second.
-: - VBR/Stereo - Portable, 50-70 Kb/s (HE AAC) / Actual bitrate ~90kbps
+'''-cbr <number>''':
+Specifies "target bitrate (streaming)" mode.  <number> is target bitrate in bits per second.
+When none of above quality/bitrate options is used, the encoder defaults to equivalent of -q 0.5
-The High Quality preset is for the archival of music, while the Small Filesize preset is for internet/streaming
+===Multipass Encoding===
-purposes.
+'''-2pass''':
+Enables two-pass encoding mode.  Note that two-pass more 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; optimal AAC profile is automatically determined from quality/bitrate settings when no override is specified.
+'''-hinttrack''': Generates an RTP hint track in output MP4 file.
+'''-ignorelength''': Ignores length signaled by WAV headers of input file. Useful for certain frontends using stdin.
 == External References ==