 | This article or section may contain original research or unverified claims.
Please help Wikipedia by adding references. See the talk page for details. | ATRAC (Adaptive TRansform Acoustic Coding) is a family of proprietary audio compression algorithms used to store information on MiniDiscs and other Sony-branded audio players. The original ATRAC-1 was first developed by Sony in 1992; the higher compression versions known as ATRAC3 and ATRAC3plus followed in 1999 and 2002, respectively. Image File history File links Circle-question. ...
See also IBMs VM operating system family, where minidisk refers to a logical unit of storage. ...
To meet Wikipedias quality standards, this article or section may require cleanup. ...
Besides Sony, other MiniDisc manufacturers such as Sharp and Panasonic also have their own versions of the ATRAC codec. In 2006, a hybrid lossless compression scheme was added to the ATRAC family.
General bitrate quality
There seems to be a general agreement that ATRAC1 usually gives transparent quality at 292 kbit/s. This is the bitrate used on original minidiscs, and the quality was usually accepted to be quite good. Later versions of ATRAC can usually be expected to be slightly better than earlier ones.
For purposes of comparison, CDs are encoded at around 1400 kbits/s, and lossless encoders can encode most CDs at around 1000 kbit/s with bitrate possibly going down to around 250 kbit/s or even lower for easy content.
There is some disagreement about the ATRAC quality (and its variants) at the lower bitrates. Judgements of sound quality are necessarily subjective. Sony claims that ATRAC3plus gives "near CD quality" at 64 kbit/s. Unfortunately this general assertion does not specify which type of source is being encoded, as a recording of a choral symphony might be more difficult to encode at 64 KBits/s than a recording of someone talking.
Bitrate quality compared to other formats Sony's official claim is that ATRAC3plus at 64 kbit/s rate provides a quality comparable to MP3 at 128 kbit/s, placing this codec in the same league as Windows Media Audio (with similar claims from Microsoft), and MPEG-4 AAC (the MP3 technical successor). Windows Media Audio (WMA) is a proprietary compressed audio file format developed by Microsoft. ...
Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. ...
Performance According to ATRAC engineers, ATRAC family is much more friendly regarding decoding chips than other schemes, and so would need far less processor power to decompress a stream [1].
Sony Walkmans offer better battery life when playing ATRAC files as compared to MP3 files. This is how the Sony NW-HDx series (NW-HD1, NW-HD3, NW-HD5) of Walkmen declare a 30-hour battery life. However, Sony didn't push for ATRAC compatibility in their Sony-Ericsson Walkman series phones (W800i, W700i, W550i, W600i and so on). It would only make sense, given the prospect of longer battery life which is necessary in multimedia phones. Sony's Xplod series of car audio CD players support ATRAC CDs - relevant, but some say not necessary considering the almost unlimited supply of electrical power that a car can provide. Sony Walkman Official Logo (2000 - current) Various products of the Walkman line The Walkman is a popular Sony brand used by the company to market its portable audio players, and is synonymously used to refer to the original Walkman portable personal stereo player and as a generic term for similar...
MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a popular digital audio encoding and lossy compression format and algorithm, designed to greatly reduce the amount of data required to represent audio, yet still sound like a faithful reproduction of the original uncompressed audio to most listeners. ...
Mobile phone Sony Ericsson is a joint venture established in 2001 by the Japanese consumer electronics company Sony Corporation and the Swedish telecommunications company Ericsson to make mobile phones. ...
The W800 Walkman, released in 2005, was the first Sony Ericsson cell phone to use the Walkman brand. ...
...
...
...
ATRAC1 ATRAC1 was first used in Sony's own theater format SDDS system in the 1990s, and in this context is a direct competitor to Dolby Digital (AC3) and DTS. SDDS uses ATRAC1 with 8 channel encoding, and with a total encoding rate over all the channels of 1168 kbit/s. SDDS stands for Sony Dynamic Digital Sound, which is a cinema sound system developed by Sony. ...
Two stacked quadrature mirror filters split the signal into 3 parts: In digital signal processing, a quadrature mirror filter is a filter bank which splits an input signal into two bands which are usually then subsampled by a factor of 2. ...
In information theory, a signal is the sequence of states of a communications channel that encodes a message. ...
- 0 to 5.5125 kHz
- 5.5125to 11.025 kHz
- 11.025 to 22.05 kHz
Full stereo (i.e., independent channel) encoding with a data rate is 292 kbit/s. Label for 2. ...
Quality is generally transparent for many people (meaning that it is not possible to tell an ATRAC encoding from the source) [citation needed]. This is most possible when using the latest algorithm, Type-S, or Type-R (Type-S only improves LP modes). Some signals will "trip" the codec and cause artifacts, though these are not usually severe enough to be obvious. In data compression or psychoacoustics, transparency is the ideal result of lossy data compression. ...
A compression artifact (or artefact) is the result of an aggressive data compression scheme applied to an image, audio, or video that discards some data which is determined by an algorithm to be of lesser importance to the overall content but which is nonetheless discernible and objectionable to the user. ...
High-frequency lowpass depends on the complexity of the material; some encodings have content clear up to 22.05 kHz. Sine waves of various frequencies; the bottom waves have higher frequencies than those above. ...
ATRAC1 can also be used in mono (one channel) mode, doubling recording time. Monaural (often shortened to mono) sound reproduction is single-channel. ...
ATRAC3 (LP2 and LP4 Modes) Three stacked QMF split the signal into 4 parts: - 0 to 2.75625 kHz (DC to f/16)
- 2.75625 to 5.5125 kHz (f/16 to f/8)
- 5.5125 to 11.025 kHz (f/8 to f/4)
- 11.025 to 22.05 kHz (f/4 to f/2)
RealAudio8 is an implementation of ATRAC3. - LP2 Mode
This uses a 132 kbit/s data rate, the quality of which is advertised to be similar to that of MP3 encoded at a similar bit rate. MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a popular digital audio encoding and lossy compression format and algorithm, designed to greatly reduce the amount of data required to represent audio, yet still sound like a faithful reproduction of the original uncompressed audio to most listeners. ...
A blind test[2] (2003/02) funded by Sony (with most test tracks provided by Sony) supports the claim that ATRAC3 at 132 kbit/s produces similar quality to MP3 at comparable bitrate.
However, in an independent double-blind test[3] (2004/05) against Ogg Vorbis, AAC, and LAME VBR MP3, ATRAC3 came last. Double-blind describes an especially stringent way of conducting an experiment, usually on living, conscious, human subjects. ...
This article is about the audio compression codec. ...
Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. ...
Look up lame in Wiktionary, the free dictionary. ...
MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a popular digital audio encoding and lossy compression format and algorithm, designed to greatly reduce the amount of data required to represent audio, yet still sound like a faithful reproduction of the original uncompressed audio to most listeners. ...
Common criticisms of similar tests include the supposition that Sony did not implement the top quality ATRAC3 encoder/decoder, the DSP TYPE S, on the PC. However, ATRAC encoders are usually implemented on portables with limited power, probably making heavy-duty compression (and hence high quality compression) difficult.
- LP4 Mode
This reduces the data rate to 66 kbit/s (half that of LP2), partly by using joint stereo coding and a lowpass filter around 13.5 kHz. It allows 324 minutes to be recorded on an 80 minute MiniDisc, with the same padding required as LP2. A low-pass filter is a filter that passes low frequencies well, but attenuates (or reduces) frequencies higher than the cutoff frequency. ...
ATRAC3plus
 Atrac3plus CD playing on a Sony car stereo. This codec is used in HiMD players (e.g., "Hi-LP and Hi-SP"), Memory Stick players, VAIO Pocket, PSP console and ATRAC CD players. It is thought to be a hybrid subband/MDCT codec, though not much information has been released. It uses a relatively large transform window of 4096 samples, four times bigger than that of ATRAC3. The signal is split into 16 sub-bands before MDCT and bit allocation. Image File history File links Car_stereo_display. ...
Image File history File links Car_stereo_display. ...
A Codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. ...
Sony 128 MB Memory Stick with MagicGate support. ...
Vaio PCG-505EX 1998 VAIO, an acronym for Video Audio Integrated Operations, is a subbrand for many of Sonys computer products. ...
The PlayStation Portable (officially abbreviated as PSP) is a handheld game console released and manufactured by Sony Computer Entertainment. ...
An Apline in car cd player (head unit) A compact disc player or CD player is an electronic device to play audio from compact discs. ...
The available data encoding rates are 48 kbit/s, 64 kbit/s, and 256 kbit/s. In the recently released Sonic Stage version 3.2 and 3.3 some more bitrates have been introduced, the available bitrates are: 48, 64, 96, 128, 160, 192, 256, 320 and 352 kbit/s. However the newer bitrates are not compatible with older hardware decoders.
Minidiscs recorded in this format are incompatible with older players.
In a test conducted by an independent firm [4], but financed by Sony, it was concluded that ATRAC3plus at 64 kbit/s is equal in subjective sound quality to MP3 at 128 kbit/s, or AAC at 96 kbit/s.
While ATRAC3plus at 64 kbit/s is quite competitive, such a strong result seems quite surprising, considering that another Sony-funded test concluded that ATRAC3 at 132 kbit/s produces similar quality to MP3 at comparable bitrate (see upper section), and that it is unlikely that ATRAC3plus at 64 kbit/s and ATRAC3 at 132 kbit/s would provide similar quality[citation needed].
To convert audio to ATRAC3+ you will need Sony's SonicStage software (free download), or a professional suite like Sony's SoundForge Pro 8.0d or Vegas 7.0 SonicStage is the name for Sony software that is used for managing portable devices when they are plugged into a computer running Windows. ...
See also A lossy data compression method is one where compressing data and then decompressing it retrieves data that may well be different from the original, but is close enough to be useful in some way. ...
MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a popular digital audio encoding and lossy compression format and algorithm, designed to greatly reduce the amount of data required to represent audio, yet still sound like a faithful reproduction of the original uncompressed audio to most listeners. ...
External links - ATRACLife - News portal, discussion forums and downloads related to ATRAC.
- ATRAC technology page - Official site about ATRAC hosted on Sony webpages.
- InfoAnarchy Atrac3 page - A somewhat more technical and less theoretical page on ATRAC3. Includes links to audio output conversion software.
| 
Feeds |
Contact