MiniDisc
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|
Compact Cassette, Compact disc | |
Extended to | MD Data, Hi-MD |
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Released | November 1992[1] |
Discontinued | March 2013 |
Optical discs |
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MiniDisc (MD) is an erasable
By March 2011 Sony had sold 22 million MD players, but halted further development.[6] Sony ceased manufacturing and sold the last of the players by March 2013.[7]
Market history
In 1983, just a year after the introduction of the compact disc, Kees Schouhamer Immink and Joseph Braat presented the first experiments with erasable magneto-optical compact discs during the 73rd AES Convention in Eindhoven.[8] It took almost 10 years, however, before their idea was commercialized.
Sony's MiniDisc was one of two rival digital systems introduced in 1992 that were intended to replace the
Relegating DAT to professional use, Sony set to work to come up with a simpler, more economical digital home format. By the time Sony came up with the MiniDisc in late 1992, Philips had introduced a competing system, DCC, on a magnetic tape cassette. This created marketing confusion very similar to the
Despite having a loyal customer base largely of musicians and audio enthusiasts,[
The slow uptake of MiniDisc was attributed to the small number of pre-recorded albums available on MD, because relatively few record labels embraced the format. The initial high cost of equipment and blank media was also a factor. Additionally, home MiniDisc decks were less widely available, with most consumers instead connecting a portable MD device to their hi-fi system in order to record.
MiniDisc technology was faced with new competition from the recordable compact disc (CD-R) when it became more affordable to consumers beginning around 1996. Initially, Sony believed that it would take around a decade for CD-R prices to become affordable – the cost of a typical blank CD-R disc was around $12 in 1994 – but CD-R prices fell much more rapidly than envisioned, to the point where CD-R blanks sank below $1 per disc by the late 1990s, compared to at least $2 for the cheapest 80-minute MiniDisc blanks.
The biggest competition for MiniDisc came with the emergence of
By 2007, because of the waning popularity of the format and the increasing popularity of solid-state MP3 players, Sony was producing only one model, the Hi-MD MZ-RH1, available as the MZ-M200 in North America packaged with a Sony microphone and limited macOS software support.[9][10][11]
The MZ-RH1 allowed users to freely move uncompressed digital recordings back and forth from the MiniDisc to a computer without the copyright protection limitations previously imposed upon the NetMD series. This allowed the MiniDisc to better compete with HD recorders and MP3 players. However, most pro users like broadcasters and news reporters had already abandoned MiniDisc in favor of solid-state recorders, because of their extended recording time, open digital content sharing, high-quality digital recording capabilities and reliable, lightweight design.
On 7 July 2011, Sony announced that it would no longer ship MiniDisc Walkman products as of September 2011,[6] effectively killing the format.[12]
On 1 February 2013, Sony issued a press release on the Nikkei stock exchange that it would cease shipment of all MD devices, with last of the players to be sold in March 2013. However, it would continue to sell blank discs and offer repair services.[2] Other manufacturers continued to release MiniDisc players long after Sony stopped, with TEAC & TASCAM producing new decks up until 2020 when both its consumer and professional products, TEAC MD-70CD and TASCAM MD-CD1MKIII, were discontinued.[13]
Design
Physical characteristics
The disc is fixed in a cartridge (68×72×5 mm) with a sliding door, similar to the casing of a 3.5"
MiniDiscs use a mastering process and optical playback system that is very similar to CDs. The recorded signal of the premastered pits and of the recordable MD are also very similar.
Differences from cassette and CDs
MiniDiscs use rewritable magneto-optical storage to store data. Unlike
The beginning of the disc has a table of contents (TOC, the System File area), which stores the start positions of the various tracks, as well as metadata (title, artist) and free blocks. Unlike a conventional cassette, a recorded song does not need to be stored as one piece on the disc, it can be scattered in fragments, similar to a hard drive. Early MiniDisc equipment had a fragment granularity of 4 seconds of audio. Fragments smaller than the granularity are not monitored, which may lead to the usable capacity of a disc shrinking over time. No means of defragmenting the disc is provided in consumer-grade equipment.
All consumer-grade MiniDisc devices have a copy-protection scheme called the Serial Copy Management System. An unprotected disc or song can be copied without limit, but the copies can no longer be digitally copied. However, as a concession, the last Hi-MD players can upload to PC a digitally recorded file which can be resaved as a WAV (PCM) file and thus replicated.
Audio data compression
The digitally encoded audio signal on a MiniDisc has traditionally been
ATRAC was devised to allow MiniDisc to have the same runtime as a CD. ATRAC reduces the 1.4 Mbit/s of a CD to a 292 kbit/s data stream,[14] roughly a 5:1 reduction. ATRAC was also used on nearly all flash memory Walkman devices until the 8 series.
The ATRAC codec differs from uncompressed PCM in that it is a
There have been four versions of ATRAC, each claimed by Sony to more accurately reflect the original audio. Early players are guaranteed to play later version ATRAC audio. Version 1 could only be copied on consumer equipment three or four times before artifacts became objectionable, as the ATRAC on the recorder attempted to compress the already compressed data. By version 4, the potential number of generations of copy had increased to around 15 to 20 depending on audio content.
The latest versions of Sony's ATRAC are ATRAC3 and ATRAC3plus. Original ATRAC3 at 132 kbit/s (also known as ATRAC-LP2 mode) was the format that was used by Sony's defunct Connect audio download store. ATRAC3plus was not used in order to retain backwards compatibility with earlier NetMD players.
In the MiniDisc's final iteration, Hi-MD, uncompressed
Anti-skip
MiniDisc has a feature that prevents disc skipping under all but the most extreme conditions. Older CD players had been a source of annoyance to users as they were prone to mistracking from vibration and shock. MiniDisc solved this problem by reading the data into a memory buffer at a higher speed than was required before being read out to the digital-to-analog converter at the standard rate of the format. The size of the buffer varies by model.
If a MiniDisc player is bumped, playback continues unimpeded while the laser repositions itself to continue reading data from the disc. This feature allows the player to stop the spindle motor for significant periods, increasing battery life.
A buffer of at least six seconds is required on all MiniDisc players, whether portable or full-sized units. This ensures uninterrupted playback in the presence of file
Operation
The data structure and operation of a MiniDisc is similar to that of a computer's
The data structure of the MiniDisc, where music is recorded in a single stream of bytes while the TOC contains pointers to track positions, allows for
At the end of recording, after the "Stop" button has been pressed, the MiniDisc may continue to write music data for a few seconds from its memory buffers. During this time, it may display a message ("Data Save", on at least some models) and the case will not open. After the audio data is written out, the final step is to write the TOC track denoting the start and endpoints of the recorded data. Sony points out in the manual that the power should not be interrupted or the unit exposed to undue physical shock during this time.
Copy protection
All MiniDisc recorders use the SCMS copy protection system which uses two bits in the S/PDIF digital audio stream and on disc to differentiate between "protected" vs. "unprotected" audio, and between "original" vs. "copy":
- Recording digitally from a source marked "protected" and "original" (produced by a prerecorded MD or an MD that recorded an analogue input) was allowed, but the recorder would change the "original" bit to the "copy" state on the disc to prevent further copying of the copy. A CD imported via a digital connection does not have the SCMS bits (as the CD format predates SCMS), but the recording MD recorder treats any signal where the SCMS bits are missing as protected and original. The MD copy, therefore, cannot be further copied digitally.
- Recording digitally from a source marked "protected" and "copy" was not allowed: an error message would be shown on the display.
- Recording digitally from a source marked "unprotected" was also allowed; the "original/copy" marker was ignored and left unchanged.
Recording from an analogue source resulted in a disc marked "protected" and "original" allowing one further copy to be made (this contrasts with the SCMS on the Digital Compact Cassette where analogue recording was marked as "unprotected").
In recorders that could be connected to a PC via USB, it was possible to transfer audio from the PC to the MiniDisc recorder, but for many years it was not possible to transfer audio the other direction. This restriction existed in both the SonicStage software and in the MiniDisc player itself. SonicStage V3.4 was the first version of the software where this restriction was removed, but it still required a MiniDisc recorder/player that also had the restriction removed. The Hi-MD model MZ-RH1 was the only such player available.
Format extensions
MD Data
MD Data, a format for storing computer data, was announced by Sony in 1993.[16] Its media were generally incompatible with standard audio MiniDiscs.[17] MD Data can not write to audio MDs, but only the considerably more expensive data blanks. It did see some success in a small number of multi-track recorders such as Sony's MDM-X4, Tascam's 564 (which could also record using standard audio MD discs, albeit only two tracks), and Yamaha's MD8, MD4, & MD4S.
MD Data2
In 1997, MD Data2 blanks were introduced with 650 MB. They were only implemented in Sony's short-lived MD-based camcorder, the DCM-M1.
MDLP
In 2000, Sony announced MDLP (MiniDisc Long Play), which added new recording modes based on the new codec ATRAC3. In addition to the standard, high-quality mode, now called SP, MDLP adds LP2 mode, which doubles the recording time – 160 minutes on an 80-minute disc – of good-quality stereo sound, and LP4, which allows four times more recording time – 320 minutes on an 80-minute disc – of medium-quality stereo sound.
The
Tracks recorded in LP2 or LP4 mode play back as silence on non-MDLP players.
NetMD
Debuting in late 2001, NetMD recorders allow music files to be transferred from a computer to a recorder (but not in the other direction) over a USB connection. In LP4 mode, speeds of up to 32× real-time are possible and three Sony NetMD recorders (MZ-N10, MZ-N910, and MZ-N920) are capable of speeds up to 64× real-time. NetMD recorders all support MDLP.
When transferring music in SP mode using NetMD with SonicStage, what is transferred is actually padded LP2. That is to say that the quality of the music is that of LP2 but recorded as SP.
NetMD is a proprietary protocol that initially required proprietary software such as SonicStage. A free *nix based implementation, libnetmd, has been developed. The library allows the user to upload SP files in full quality. In 2019, a programmer named Stefano Brilli compiled the linux-minidisc CLI into a web browser-based application,[18] allowing users to transfer music via USB on modern devices.[19]
Hi-MD
Hi-MD is a further development of the MiniDisc format. Hi-MD media will not play on non-Hi-MD equipment, including NetMD players. The Hi-MD format, introduced in 2004, marked a return to the data storage arena with its 1 GB discs and ability to act as a USB drive.[20] Hi-MD units allow the recording and playback of audio and data on the same disc, and can write both audio and data to standard MiniDisc media – an 80-minute MiniDisc blank could be formatted to store 305 MB of data.
Recording and transfer modes
Modes marked in green are available for recordings made on the player, while those marked in red are available for music transferred from a PC. Capacities are official Sony figures; real world figures are usually slightly higher. Native MP3 support was added in second-generation Hi-MD players in the spring of 2005.[21] SonicStage version 3.4, released in Feb 2006,[22] introduced ripping CDs in bitrates 320 and 352[23] and added track transfer in ATRAC 192 kbit/s to Hi-MD devices.
Name | Bitrate (kbit/s) |
Codec | Availability and capacity (min) | ||||
---|---|---|---|---|---|---|---|
Standard player | MDLP player | Hi-MD player | |||||
80-minute disc | 80-minute disc (HiMD formatted) |
1 GB Hi-MD disc | |||||
Stereo SP | 292 | ATRAC | 80 | 80 | 80 | n/a | n/a |
Mono SP | 146 | ATRAC | 160 | 160 | 160 | n/a | n/a |
LP2 | 132 | ATRAC3 | n/a | 160 | 160 | 290 | 990 |
– | 105 | ATRAC3 | n/a | 127 | 127 | 370 | 1250 |
LP4 | 66 | ATRAC3 | n/a | 320 | 320 | 590 | 1970 |
– | 48 | ATRAC3plus | n/a | n/a | n/a | 810 | 2700 |
Hi-LP | 64 | ATRAC3plus | n/a | n/a | n/a | 610 | 2040 |
Hi-SP | 256 | ATRAC3plus | n/a | n/a | n/a | 140 | 475 |
PCM | 1411.2 | Linear PCM | n/a | n/a | n/a | 28 | 94 |
See also
- Capacitance Electronic Disc (SelectaVision) – an RCA-developed format that uses a disc inside a sleeve, like MD
- Fidelipac
- Universal Media Disc (UMD) – a similar Sony format, but read-only
- Mini CD
- MiniDVD
- Mini Blu-ray
References
- ^ Woudenberg, Eric. "Sony MZ-1". Retrieved 30 July 2022.
- ^ a b "Sony To End Shipments of MiniDisc Players". The Nikkei. Retrieved 4 February 2013.
- ^ Sony history Retrieved 1 June 2016
- ^ Emeran, Riyad (8 April 2008). "Music on the Move: MiniDisc". TrustedReviews. Archived from the original on 13 May 2008.
- ^ "Sony bids farewell to the MiniDisc".
- ^ a b "Sony To Wind Up MiniDisc Walkman Shipments". Nikkei.com. 7 July 2011. Archived from the original on 11 July 2011.
- ^ "Sony says sayonara to MiniDisc, will sell its last players in March". Engadget.com. 1 February 2013. Retrieved 16 May 2016.
- ^ K. Schouhamer Immink and J. Braat (1984). "Experiments Toward an Erasable Compact Disc". J. Audio Eng. Soc. 32: 531–538.
- ^ "Sony MZ-RH1 User Manual" (PDF).
- ^ "Sony MZ-M200 Hi-MD Recorder with Stereo Microphone". CNET. 5 December 2007.
- ^ "Hi-MD Music Transfer for Mac Ver.2.0". Sony. 15 July 2006.
- ^ Faulkner, Joey (24 September 2012). "MiniDisc, The Forgotten Format". The Guardian UK. Archived from the original on 4 June 2023.
- ^ "Mdデッキ生産の終息について". 株式会社 松本無線音響設備. 27 January 2020. Archived from the original on 25 June 2023.
- ^ Woudenberg, Eric. "MiniDisc FAQ: Audio Topics - What is the bit rate of the Minidisc's ATRAC audio after compression?". Minidisc Community Portal. Retrieved 30 July 2022.
- ^ "Sony MDS-JE780 Minidisc Deck Manual". HiFi Engine. Archived from the original on 3 October 2020. Retrieved 30 May 2020.
- ^ "Reviews / Sony's Mini-MO". Byte. August 1995. Archived from the original on 20 December 1996. Retrieved 22 December 2023.
- ^ "MiniDisc MD-Data Product Table". The MiniDisc Community Portal. Retrieved 22 December 2023.
- ^ Brilli, Stefano (26 March 2020). "The Web MiniDisc App". Archived from the original on 25 June 2023.
- ^ "Remember MiniDisc? Here's How You Can Still Use It in 2020". TechTelegraph. 25 July 2020. Archived from the original on 19 December 2020.
- ^ "Sony introduces Hi-MD Walkman digital music players". Sony. 7 January 2004. Archived from the original on 1 February 2004.
- ^ "Sony Business Solutions & Systems - Featured". 15 April 2008. Archived from the original on 15 April 2008.
- ^ "Overseas Model Customer Support". 7 April 2006. Archived from the original on 7 April 2006.
- ^ "Overseas Model Customer Support". 5 February 2006. Archived from the original on 5 February 2006.