Difference between revisions of "AAC encoders"
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| − | These are some known AAC encoder implementations. | + | These are some known [[AAC]] encoder implementations. |
| − | =Nero AAC= | + | ==Nero AAC== |
| − | 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 distributed with Nero 6 which incorporates Nero Digital. Generally accepted to have the highest quality [[VBR]] LC AAC implementation (although [[iTunes]] CBR beats Nero's VBR 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. |
| − | Nero Digital. Generally accepted to have the highest quality [[VBR]] LC AAC implementation (although | + | |
| − | + | ||
| − | 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== | + | ===Recomended Nero AAC Presets=== |
| − | 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]). | + | 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. |
| − | ===High Quality=== | + | ====High Quality==== |
: - VBR/Stereo - Streaming, 100-120 Kb/s (LC AAC) / Actual bitrate ~150kbps | : - VBR/Stereo - Streaming, 100-120 Kb/s (LC AAC) / Actual bitrate ~150kbps | ||
| − | ===Portable=== | + | ====Portable==== |
: - VBR/Stereo - Internet, 90-100 Kb/s (LC AAC) / Actual bitrate ~128kbps | : - VBR/Stereo - Internet, 90-100 Kb/s (LC AAC) / Actual bitrate ~128kbps | ||
| − | ===Small Filesize=== | + | ====Small Filesize==== |
: - VBR/Stereo - Portable, 50-70 Kb/s (HE AAC) / Actual bitrate ~90kbps | : - VBR/Stereo - Portable, 50-70 Kb/s (HE AAC) / Actual bitrate ~90kbps | ||
| − | The High Quality preset is for the archival of music, while the Small Filesize preset is for internet/streaming | + | The High Quality preset is for the archival of music, while the Small Filesize preset is for internet/streaming purposes. |
| − | purposes. | + | |
| − | More information can be found in the [ftp://ftp6.nero.com/infosheets/Nero_Digital/db_nerodigital5.pdf Nero Digital PDF] | + | More information can be found in the [ftp://ftp6.nero.com/infosheets/Nero_Digital/db_nerodigital5.pdf Nero Digital PDF] and on the [http://www.nerodigital.com/ Nero Digital Website]. |
| − | and on the [http://www.nerodigital.com/ Nero Digital Website]. | + | |
| − | |||
| − | + | ==iTunes AAC== | |
| − | + | ||
| − | + | ||
| − | + | Another commercial AAC implementation, [[iTunes]] AAC is known to be one of the highest quality medium-bitrate [[CBR]] LC AAC encoders. | |
| − | + | ||
| − | + | The codec is available for free through the [[iTunes]] Digital Jukebox. | |
More information can be found at the [http://www.apple.com/mpeg4/aac/ Apple Website] | More information can be found at the [http://www.apple.com/mpeg4/aac/ Apple Website] | ||
| − | + | The recommended high quality encoding setting is 160kbps, or 128kbps for portable use. | |
| − | FAAC is a free and open-source LC AAC encoder. Its quality has improved drastically over the last few months and | + | |
| − | is now a viable alternative to the commercial encoders (although, at least at 128kbps, not as good as the free | + | ==FAAC== |
| − | iTunes encoder). | + | |
| + | [[FAAC]] is a free and open-source LC AAC encoder. Its quality has improved drastically over the last few months and is now a viable alternative to the commercial encoders (although, at least at 128kbps, not as good as the free iTunes encoder). | ||
More information can be found at [http://www.audiocoding.com/ AudioCoding] | More information can be found at [http://www.audiocoding.com/ AudioCoding] | ||
| − | |||
| − | Compaact is one of the newest AAC encoders. Like Nero AAC, compaact is not free, however it does offer an | + | ==HHI/zPlane (Compaact!)== |
| − | impressive feature set. Roberto Amorim's last AAC test showed that at 128kbps, Compaact! is tied with both the FAAC | + | |
| − | and Coding Technologies (Real) encoders. Compaact! features both the LC and Main Object Types, CBR, VBR, | + | Compaact is one of the newest AAC encoders. Like Nero AAC, compaact is not free, however it does offer an impressive feature set. Roberto Amorim's last AAC test showed that at 128kbps, Compaact! is tied with both the FAAC and Coding Technologies (Real) encoders. Compaact! features both the LC and Main Object Types, CBR, VBR, Multichannel high resolution (24bit/96kHz) encoding, and command line support. |
| − | Multichannel high resolution (24bit/96kHz) encoding, and command line support. | + | |
For portable encoding, try -q5 to -q6. For music archive purposes, try -q7 to -q8. | For portable encoding, try -q5 to -q6. For music archive purposes, try -q7 to -q8. | ||
| Line 65: | Line 54: | ||
| − | =PsyTEL= | + | ==PsyTEL== |
| − | The creation of Ivan Dimkovic (who now works on Nero AAC), PsyTEL AAC was one of the first AAC encoders. Its | + | The creation of Ivan Dimkovic (who now works on Nero AAC), PsyTEL AAC was one of the first AAC encoders. Its multi-channel support has bugs that make it unusable, but its 2 channel had the best quality available in its day. Since the implementation of Nero AAC, this codec has become obselete. It's is now outclassed by both Nero AAC and [[iTunes]]. |
| − | multi-channel support has bugs that make it unusable, but | + | |
| − | Since the implementation of Nero AAC, this codec has become obselete. It's is now outclassed by both Nero AAC | + | |
| − | and iTunes. | + | |
The PsyTEL encoder can be found in the AAC section of [http://www.rjamorim.com/rrw/ ReallyRareWares] | The PsyTEL encoder can be found in the AAC section of [http://www.rjamorim.com/rrw/ ReallyRareWares] | ||
| − | ==Usability (Psytel aacenc/fastenc)== | + | ===Usability (Psytel aacenc/fastenc)=== |
; -tape | ; -tape | ||
| Line 85: | Line 71: | ||
; -ultra | ; -ultra | ||
| + | For music encoding. The quality ranges from -tape (lowest [[VBR]] quality) to -ultra (highest VBR quality). Ultra is considered overkill for most audio tracks, i.e: shouldn't be used except for extremely difficult music signals. Example: aacenc -extreme -if "audio file.wav" | ||
| − | + | ===Encoder switches (Psytel aacenc/fastenc)=== | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | ==Encoder switches (Psytel aacenc/fastenc)== | + | |
; -if | ; -if | ||
| Line 136: | Line 119: | ||
: (perceptual noise substitution) - Improves the quality at very low Bitrates. Should be used only at 64kbps or less. Example: aacenc -br 56 -pns -if "audio file.wav" | : (perceptual noise substitution) - Improves the quality at very low Bitrates. Should be used only at 64kbps or less. Example: aacenc -br 56 -pns -if "audio file.wav" | ||
| − | |||
| − | Imagine Technology provides an MPEG-4 LC AAC plugin for Adobe Audition. This plugin provides file input and output | + | ==Imagine== |
| − | for the MPEG-4 audio specification, defined in ISO/IEC 14496-3. More info can be found at the | + | |
| − | [http://imaginetechnology.net/plugins.html imagine website]. | + | Imagine Technology provides an [[MPEG-4]] LC AAC plugin for [[Adobe Audition]]. This plugin provides file input and output for the MPEG-4 audio specification, defined in ISO/IEC 14496-3. More info can be found at the [http://imaginetechnology.net/plugins.html imagine website]. |
| − | =Coding Technologies= | + | ==Coding Technologies== |
| − | RealNetworks has incorporated Coding | + | RealNetworks has incorporated Coding Technologies/FhG's MPEG-4 AAC / aacPlus™ technology and software within RealNetworks’ software products. As a result, in the newest version of RealProducer 10, AAC has replaced [[ATRAC]]3 as the high bitrate audio codec, and that software can encode AAC files wrapped in the [[MP4]] container. In addition, the Producer SDK on Windows also includes HE-AAC encoding. More info can be found at [http://www.realnetworks.com/company/press/releases/2004/codingtech.html RealNetworks' press release], as well as Coding Technologies' [http://www.codingtechnologies.com/products/aacPlus.htm aacPlus page]. |
| − | software products. As a result, in the newest version of RealProducer 10, AAC has replaced [[ATRAC]]3 as the high bitrate | + | |
| − | audio codec, and that software can encode AAC files wrapped in the | + | |
| − | SDK on Windows also includes HE-AAC encoding. More info can be found at | + | |
| − | [http://www.realnetworks.com/company/press/releases/2004/codingtech.html RealNetworks' press release], as well as | + | |
| − | Coding Technologies' [http://www.codingtechnologies.com/products/aacPlus.htm aacPlus page]. | + | |
| − | =FhG= | + | ==FhG== |
[http://www.iis.fraunhofer.de/amm/techinf/aac/ Audio & Multimedia MPEG-2 AAC] | [http://www.iis.fraunhofer.de/amm/techinf/aac/ Audio & Multimedia MPEG-2 AAC] | ||
| − | =Emuzed= | + | ==Emuzed== |
| − | Emuzed develops and sells various products and technologies for the PC multimedia and embedded multimedia markets. | + | Emuzed develops and sells various products and technologies for the PC multimedia and embedded multimedia markets. They have ported and optimized codecs for MPEG-4 ASP and AAC LC for a chip vendor preparing to offer bundled multimedia hardware and software. More info can be found at their [http://www.emuzed.com/encoders.html encoders & decoders] page. |
| − | They have ported and optimized codecs for MPEG-4 ASP and AAC LC for a chip vendor preparing to offer bundled | + | |
| − | multimedia hardware and software. More info can be found at their [http://www.emuzed.com/encoders.html encoders & decoders] | + | |
| − | page. | + | |
| − | =NEC= | + | ==NEC== |
| − | NEC Corporation has developed an LC AAC decoding algorithm for mobile devices. They have also developed a codec | + | NEC Corporation has developed an LC AAC decoding algorithm for mobile devices. They have also developed a codec named MPEG-4 AAC Ext.1, which they claim decreases bitrate while maintaining the same audio quality. The new MPEG-4 AAC Ext.1 coding technology also supports high compatibility with current MPEG-4 AAC. For more information, see [http://www.neceurope.com/release.asp?parentid=671&Area=1 NEC's press release]. |
| − | named MPEG-4 AAC Ext.1, which they claim decreases bitrate while maintaining the same audio quality. The new MPEG-4 | + | |
| − | AAC Ext.1 coding technology also supports high compatibility with current MPEG-4 AAC. For more information, see | + | |
| − | [http://www.neceurope.com/release.asp?parentid=671&Area=1 NEC's press release]. | + | |
| − | =Panasonic= | + | ==Panasonic== |
| − | Panasonic has developed | + | Panasonic has developed an HE AAC codec together with NEC and Coding Technologies as described in |
[http://www.telos-systems.com/techtalk/hosted/m4-in-30100%20(M4IF_HE_AAC_paper).pdf this MPEG Industry Forum paper]. | [http://www.telos-systems.com/techtalk/hosted/m4-in-30100%20(M4IF_HE_AAC_paper).pdf this MPEG Industry Forum paper]. | ||
| − | =Real/Helix Producer= | + | ==Real/Helix Producer== |
[[Real Producer|Real/Helix Producer]]: http://helixcommunity.org | [[Real Producer|Real/Helix Producer]]: http://helixcommunity.org | ||
Revision as of 02:05, 18 June 2005
These are some known AAC encoder implementations.
Contents
Nero AAC
A commercial implementation of both LC AAC and HE AAC, Nero AAC is distributed with Nero 6 which incorporates Nero Digital. Generally accepted to have the highest quality VBR LC AAC implementation (although iTunes CBR beats Nero's VBR 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
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 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.
High Quality
- - VBR/Stereo - Streaming, 100-120 Kb/s (LC AAC) / Actual bitrate ~150kbps
Portable
- - VBR/Stereo - Internet, 90-100 Kb/s (LC AAC) / Actual bitrate ~128kbps
Small Filesize
- - VBR/Stereo - Portable, 50-70 Kb/s (HE AAC) / Actual bitrate ~90kbps
The High Quality preset is for the archival of music, while the Small Filesize preset is for internet/streaming purposes.
More information can be found in the Nero Digital PDF and on the Nero Digital Website.
iTunes AAC
Another commercial AAC implementation, iTunes AAC is known to be one of the highest quality medium-bitrate CBR LC AAC encoders.
The codec is available for free through the iTunes Digital Jukebox.
More information can be found at the Apple Website
The recommended high quality encoding setting is 160kbps, or 128kbps for portable use.
FAAC
FAAC is a free and open-source LC AAC encoder. Its quality has improved drastically over the last few months and is now a viable alternative to the commercial encoders (although, at least at 128kbps, not as good as the free iTunes encoder).
More information can be found at AudioCoding
HHI/zPlane (Compaact!)
Compaact is one of the newest AAC encoders. Like Nero AAC, compaact is not free, however it does offer an impressive feature set. Roberto Amorim's last AAC test showed that at 128kbps, Compaact! is tied with both the FAAC and Coding Technologies (Real) encoders. Compaact! features both the LC and Main Object Types, CBR, VBR, Multichannel high resolution (24bit/96kHz) encoding, and command line support.
For portable encoding, try -q5 to -q6. For music archive purposes, try -q7 to -q8.
More information can be found at the Compaact website.
PsyTEL
The creation of Ivan Dimkovic (who now works on Nero AAC), PsyTEL AAC was one of the first AAC encoders. Its multi-channel support has bugs that make it unusable, but its 2 channel had the best quality available in its day. Since the implementation of Nero AAC, this codec has become obselete. It's is now outclassed by both Nero AAC and iTunes.
The PsyTEL encoder can be found in the AAC section of ReallyRareWares
Usability (Psytel aacenc/fastenc)
- -tape
- -radio
- -internet
- -streaming
- -normal
- -extreme
- -archive
- -ultra
For music encoding. The quality ranges from -tape (lowest VBR quality) to -ultra (highest VBR quality). Ultra is considered overkill for most audio tracks, i.e: shouldn't be used except for extremely difficult music signals. Example: aacenc -extreme -if "audio file.wav"
Encoder switches (Psytel aacenc/fastenc)
- -if
- Input filename. The name of the track to be encoded (must be a .wav file)
- -of
- Output filename. May be omitted, because encoder will automatically set best output file name.
- -br
- BitRate switch. Sets the number of bits utilized per second for the encoding process. Example: aacenc -br 192 -if "audio file.wav"
- -vbrhi
- High quality [VBR] mode. Can be used with -br switch to select base BitRate. If -br is not specified, it takes as default 64kbps/channel. Example: aacenc -br 192 -vbrhi -if "audio file.wav"
- -vr
- Lower quality [VBR] mode. Recommended for internet streaming. Example: aacenc -vr -if "audio file.wav"
- -c
- LowPassFilter cut-off (in hertz). Not recommended. Example: aacenc -br 128 -c 15995 -if "audio file.wav"
- -qual
- Encoder quality level (1 to 9). 9 is usually taken as default, but you can use smaller numbers if you need high speed and high quality isn't essential. Example: aacenc -br 192 -qual 9 -if "audio file.wav"
- -adif
- Use adif instead of adts (default) header. For compatibility with some decoder software and hardware players. Example: aacenc -br 192 -adif -if "audio file.wav"
- -nh
- No headers (raw iso aac stream). For decoder compatibility, and can improve. Example: aacenc -br 192 -nh -if "audio file.wav"
- -profile "x"
- Choose iso aac encoding profile:
- 0 - low complexity (default, recommended)
- 1 - main (not recommended, buggy)
- 2 - main ltp (mpeg-4 only)
- Only lc profile is playable on hardware players so far. Example: aacenc -br 192 -profile 2 -if "audio file.wav"
- -ihsc
- Improved human speech coding. Best for human voice encoding. Not recommended for low Bitrates or [CBR] coding. Example: aacenc -vbrhi -br 192 -ihsc -if "audio file.wav"
- -low_ath
- Tells encoder to use highest sensitivity threshold of audibility. Not recommended on Bitrates lower than 192kbps. Example: aacenc -br 192 -low_ath -if "audio file.wav"
- -pns
- (perceptual noise substitution) - Improves the quality at very low Bitrates. Should be used only at 64kbps or less. Example: aacenc -br 56 -pns -if "audio file.wav"
Imagine
Imagine Technology provides an MPEG-4 LC AAC plugin for Adobe Audition. This plugin provides file input and output for the MPEG-4 audio specification, defined in ISO/IEC 14496-3. More info can be found at the imagine website.
Coding Technologies
RealNetworks has incorporated Coding Technologies/FhG's MPEG-4 AAC / aacPlus™ technology and software within RealNetworks’ software products. As a result, in the newest version of RealProducer 10, AAC has replaced ATRAC3 as the high bitrate audio codec, and that software can encode AAC files wrapped in the MP4 container. In addition, the Producer SDK on Windows also includes HE-AAC encoding. More info can be found at RealNetworks' press release, as well as Coding Technologies' aacPlus page.
FhG
Emuzed
Emuzed develops and sells various products and technologies for the PC multimedia and embedded multimedia markets. They have ported and optimized codecs for MPEG-4 ASP and AAC LC for a chip vendor preparing to offer bundled multimedia hardware and software. More info can be found at their encoders & decoders page.
NEC
NEC Corporation has developed an LC AAC decoding algorithm for mobile devices. They have also developed a codec named MPEG-4 AAC Ext.1, which they claim decreases bitrate while maintaining the same audio quality. The new MPEG-4 AAC Ext.1 coding technology also supports high compatibility with current MPEG-4 AAC. For more information, see NEC's press release.
Panasonic
Panasonic has developed an HE AAC codec together with NEC and Coding Technologies as described in this MPEG Industry Forum paper.
