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Opticodec-PC 1010 PE
Opticodec-PC 1010: Codec Comparisons
Audio Files
This section allows you to assess the subjective audio quality of different permutations of several currently available lossy audio codecs. It is one of the most comprehensive comparisons available on the Internet.
We chose these particular audio sources because they tend to stress lossy codecs for various reasons, which will become apparent after you listen to some of these samples. The source audio was digitally extracted from the original label CDs. There were no physical cables or any analog-to-digital or digital-to-analog conversions in the extraction process. The source audio extraction used software error correction and is thus bit-accurate.
Track 1 — There is a slight left and right channel delay caused by slight misalignment of the analog tape recorder used to master this recording. It should sound fine in stereo. This can be verified by listening to the mono sum or the mono PCM sample. Many poorly designed codecs will smear this in stereo.
Track 2 — An abundance of high frequency energy will cause high frequency smearing in many codecs.
Track 3 — Female voice is the most difficult test for codec voice performance. Many codecs will produce a tunnel effect on voice.
Track 4 — Uncorrelated stereo material taxes the codec ability to take advantage of common material between left and right channels. This file is mainly useful in assessing stereo codecs.
A high-speed Internet connection will facilitate your evaluation. However, since the files are not streamed and must be downloaded, it is not required.
It is important to use the correct player application and version when you listen to these files. Many player features are changing to accommodate the new AAC/HE-AAC/aacPlus codecs in the various formats and containers. All files are in their native file format and need the correct player application to ensure that they will play properly with the correct reciprocal codec. We did this intentionally so that you can verify that these files are in the format they claim to be. Therefore, it will be necessary to install these players to perform an accurate evaluation. In order to play all the files here, you will need a minimum of Winamp 5.2, RealPlayer 10, and Windows Media Player 9. QuickTime 6 is optional, but useful to assess downward compatibility of HE AAC/aacPlus on an AAC only player, hopefully only for the time being. Apple, are you listening?
Installing multiple media players on a single computer can sometimes be problematic. However, through careful installation, it is possible to have these players coexist without conflict. You must make sure that file associations are properly assigned to their player applications and that no player application appropriates an incompatible file type.
Unfortunately most Microsoft Windows installations include Windows Media Player by default. WMP supports some non-Microsoft audio file formats, including some it should not, as they are either not correctly or not fully supported. This causes either poor quality or complete failure to play. Below is a chart of tested and recommended players and file formats for Microsoft Windows computer systems. Use this chart to make sure the correct player is associated with the correct file types.
RECOMMENDED PLAYER FILE TYPE ASSOCIATIONS
| File Type | Winamp 5.07 | RealPlayer 10.5 | QuickTime 6.52 | WMP 9.0/10.0 |
| .aac |
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| .mp4 |
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| .mp3 |
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| .mp2 |
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| .ogg |
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| .rm |
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.wma
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| .m3u |
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| .pls |
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| .asx |
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| .ram |
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| .qtl |
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Notes:
.aac — Files are a lossy compressed audio format and can be either AAC or HE-AAC / aacPlus v1 or v2.
Winamp is compatible with ALL AAC formats, AAC/HE-AAC aacPlus v1 and v2. RealPlayer is compatible with AAC and HE-AAC/aacPlus v1. HE-AAC/aacPlus v2 files will play in mono.
QuickTime player is only compatible with AAC/HE-AAC/aacPlus formats that are in a QuickTime .mov or MPEG-4 .mp4 container. HE-AAC/aacPlus v1 will play in stereo without SBR and HE-AAC/aacPlus v2 will play in mono without SBR, as QuickTime does not support HE-AAC/aacPlus. The AAC codec has been rated transparent at 128kbps and above.
The .aac files here are encoded with the Orban Opticodec-PC File Encoder using Coding Technologies AAC/aacPlus.
.mov — Files are a container format very similar to MPEG-4. The files can contain several different audio and video formats and/or file/stream information. The .mov files here are audio, encoded with QDesign Music 2, and are supported by all QuickTime 6 and above and RealPlayer 10 and above players.
The QDesign Music 2 files have been encoded using Quality Optimization with the default Advanced Settings of 50% and the minimum recommended sample-rate that allows the codec to perform optimally.
.mp4 — Files are a container format. They can contain several different audio and video formats. Audio .mp4 files are also sometimes .m4a, .m4b, or .m4p files, especially from Apple iTunes. A .m4a file is exactly the same as a .mp4 file except with a file extension to designate that it is an audio file. A .m4p file is a Digital Rights Management protected .m4a file. A .m4b is exactly is exactly the same as a .mp4 file except with a file extension to designate that it is an audio book file, and can be protected or unprotected.
The .mp4 files here are encoded with either the Orban Opticodec-PC File Encoder using Coding Technologies AAC/aacPlus, or Apple QuickTime Pro, using Dolby AAC with an Encoding Quality of Best.
.mp3 — Files are a lossy compressed audio format that gained popularity for file sharing mainly because their quality is "good enough" and they provide a small file size to transport over the Internet. It is also popular for streaming, although 128kbps is required to acieve reasonable quality, making broadband mandatory for your audience. Professional applications include temporary ISDN broadcast links. "MP3" is an informal name for files and streams encoded using the MPEG1 Layer 3 algorithm. Unlike its predecessor, MPEG-1 Layer2 or the new AAC, this codec has never been rated transparent at any bitrate. Most media players support this format.
The .mp3 files here are encoded with different MPEG-1, Layer3 encoders in their highest quality modes to show their performance differences.
.mp2 — Files are a lossy compressed audio format mainly used for professional file transport, storage and playout systems.
"MP2" is an informal name for files encoded using the MPEG1 Layer 2 algorithm. This codec has been rated transparent at 256kbps and above. Most media players support this format. However, Microsoft Media Player should be avoided, as it has a confirmed computational problem that causes low-level noise. We hope that Microsoft will address this someday.
The .mp2 files here are encoded with the QDesign MPEG-1, Layer2 encoder in the highest quality mode. Note that MPEG-1 Layer2 was not designed for low bitrates below 128kbps stereo. The low bitrate samples here are mainly for reference only.
.ogg — Ogg is an open-source container format supporting a variety of codecs, the most popular of which is the lossy compressed audio format Vorbis. The combination of the two is usually referred to as "Ogg Vorbis." Vorbis offers both fixed (FBR) and variable (VBR) bitrate encoding, achieving higher efficiency using variable-bitrate.
The .ogg files here are VBR which allows the highest quality and is also the most popular encoding.
.wma — Files are a lossy or lossless compressed proprietary audio format from Microsoft used mainly with Windows Media Player and gaining popularity among consumer player devices due to free distribution with Microsoft operating systems.
.wav — Files are an audio container format mainly used for linear PCM using a Microsoft RIFF header. This format is also capable of containing other types of audio formats such as ADPCM, MPEG1 Layer 3, or MPEG1 Layer 2.
The .wav files here are linear PCM.
.pls — Files are a playlist/metafile format, and are not codec specific. It is important to associate this file type with a player that is known to be compatible with the actual codec used in the file(s) or stream(s) that the playlist file specifies. Winamp is fully compatible with AAC/HE-AAC/aacPlus, MP3, and OGG, which are the most common types of files or streams specified in this playlist format. Therefore, if Winamp is associated with these playlist file types, it will play any format specified. Other players may play some formats, but not all.
.m3u — Files are a playlist/metafile format, and are not codec specific. It is important to associate this file type with a player that is known to be compatible with the actual codec used in the file(s) the playlist file specifies. By default, most installations of Microsoft Windows have this type associated with Windows Media Player, which does not support all files or streams that this playlist file is capable of describing. Winamp is fully compatible with AAC/HE-AAC/aacPlus, MP3, and OGG, which are the most common types of files or streams specified in this playlist format. Therefore, if Winamp is associated with these playlist file types, it will play any format specified. Other players may play some formats, but not all.
.asx — Files are a playlist/metafile format and are not codec specific. They can contain file/stream title and location (URL) information. They are used to ensure that Microsoft Windows Media Player opens and plays the file or stream that is described, as they are associated with Windows Media Player by default.
.ram — Files are a playlist/metafile format and are not codec specific. They can contain contain file/stream title and location (URL) information. They are used to ensure that RealPlayer opens and plays the file or stream that is described, as they are associated with RealPlayer by default.
.qtl — Files are a playlist/metafile format and are not codec specific. They can contain file/stream title and location (URL) information. They are used to ensure that QuickTime Player opens and plays the file or stream that is described, as they are associated with QuickTime Player by default. It is important to use a high fidelity audio monitor system with good loudspeakers or headphones when assessing the audio quality of these codecs. Results here speak for themselves and are surprising. Some codecs don't live up to their hype. Anyone planning to deploy wireless transmission systems, streaming audio, or audio content delivery systems using audio codec technology should choose a codec wisely. Chosing the wrong codec can prove costly.
Click here for: ENCODED AUDIO COMPARISON SAMPLES
