==== Audio MiniDiscs ====

MiniDiscs were introduced by Sony in 1992.

Originally available in 60 minute discs. Later expanded to match full-size Compact Discs in runtime; 74, and 80 minute lengths, when recorded in original **SP** format; ~292kbps encoding ATRAC.

For **NetMD/MDLP** format, [[https://www.sony.jp/CorporateCruise/Press/200007/00-0718C/ | introduced in September 2000]]. This extends run-time as follows:

   * LP2 being double: 120 min (2 hours), 148 min (2 hour, 28 min), 160 min (2 hour, 40 min), roughly halving SP encoding, ~132kbps
  * LP4 being quadruple: 240 min (4 hours), 296 min (4 hours, ~56 min), and 320 min (5 hours, 20 min), roughly quartering SP encoding ~66kbps

^Mode of Recorded Audio Data((Need to verify))    ^Track Mode (UTOC)^Result when played on MDLP unit^Result when played on non-MDLP unit|
^SP stereo|SP stereo|SP stereo|SP stereo|
| ::: |SP mono|half-speed SP mono|half-speed SP mono|
| ::: |LP2|silent|SP stereo|
| ::: |LP4|silent|half-speed SP mono|
^SP mono|SP stereo|double-speed SP mono|double-speed SP mono|
| ::: |SP mono|SP mono|SP mono|
| ::: |LP2|silent|double-speed SP mono|
| ::: |LP4|silent|SP mono|
^LP2|SP stereo|silent|silent|
| ::: |SP mono|silent|silent|
| ::: |LP2|LP2|silent|
| ::: |LP4|nonstop squeal|silent|
^LP4|SP stereo|silent|silent|
| ::: |SP mono|silent|silent|
| ::: |LP2|double-speed LP4|silent|
| ::: |LP4|LP4|silent|

**Hi-MD**, introduced in January 2004, was a nearly complete revamp of the MD system.

The most significant change is the introduction of Hi-MD media, which includes a new 1GB blank in the existing MD form-factor and a reformatting of existing MD media that doubles its capacity to 305MB. In addition, several important and long wished-for Minidisc capabilities have been incorporated into Hi-MD equipment.

  * Hi-MD recorders can be used directly as USB connected data drives on any PC supporting USB storage devices (no additional drivers needed)
  * This allowed drag-n-drop of audio (and other) files directly onto the Hi-MD disc.
      * This includes PCM (WAV) as well as standard/Hi-MD ATRAC files; additional software is needed for 1st-generation Hi-MD hardware. 2nd-generation does not
  * This introduced several new, Hi-MD-specific modes: **Hi-SP**  (256kbps) and **Hi-LP**  (64kbps) via ATRAC3plus

|

^Encoding Mode^Recording capacity<sup>(1)</sup>
| ::: ^305MB Hi-MD \\ formatted Minidisc^1GB Hi-MD Media^recording with \\ Hi-MD equipment^downloading from PC \\ to Hi-MD equipment|
|Linear PCM 1411kbps (1.4Mbps)|28m|1h 34m| yes| [[guides:linearpcm_sonicstage|yes]]|
|ATRAC3plus 256kbps "Hi-SP"|2h 20m|7h 55m| yes| yes|
|ATRAC3plus 64kbps "Hi-LP"|10h 10m|34h| yes| yes|
|ATRAC3plus 48kbps|13h 30m|45h| no| yes|
|ATRAC3 132kbps "LP2"|4h 50m|16h 30m| no| yes|
|ATRAC3 105kbps|6h 10m|20h 50m| no| yes|
|ATRAC3 66kbps "LP4"|9h 50m|32h 50m| no| yes|
|ATRAC 292kbps "SP"|//Not supported on Hi-MD media//   ||||

**Source for table below: [[http://www.minidisc.org/part_Sony_DCM-M1.html|MD Discam]]**

^ ^Current MD format^Existing MD formatted into “Hi-MD”^Hi-MD 1GB Disc^MD Data Disc|
^Data Capacity|177MB|305MB|1.0GB|650MB|
^Magneto-Optical Recording Method|Magnetic Field Modulation|Magnetic Field Modulation|Domain Wall Displacement Detection|Magnetic Field Modulation on two layer medium (record layer and record assist layer)| | | | | |
^Laser Wavelength (λ)|780nm|780nm|780nm|655nm| | | | | |
^NA of Objective Lens|0.45|0.45|0.45|0.52| | | | | |
^Diameter|64.8mm|64.8mm|64.8mm|64.8mm| | | | | |
^Thickness of Substrate|1.2mm|1.2mm|1.2mm|1.2mm (but with new substrate resin)| | | | | |
^Tracking Format|Groove Recording|Groove Recording|Groove Recording|Groove Recording| | | | | |
^Addressing|Wobbling Groove (ADIP)|Wobbling Groove (ADIP)|Wobbling Groove (ADIP)|Interlaced Wobbling Groove (ADIP with 1 address per track)| | | | | |
^Data Modulation|EFM|1-7RLL|1-7RLL|1-7RLL| | | | | |
^Data Detection|Bit by Bit|PRML|PRML|Bit by Bit| | | | | |
^Bit Length|0.59μm|0.44μm|0.16μm|0.34μm| | | | | |
^Shortest Mark Length|0.83μm|0.58μm|0.21μm| | | | | | |
^Track Pitch|1.5μm|1.5μm|1.25μm|0.95μm| | | | | |
^Data Transfer Rate|1.25Mbps @1.2m/s|4.37Mbps @2.4m/s|9.83Mbps @1.98m/s|9.4Mbps| | | | | |

----

==== Data MiniDiscs ====

Only readable/writeable in MD Data drives and devices.

MD Data: 140MB //Released July 1993//

MD Data2: 650MB //Released early 1997//

Hi-MD: 1GB //Exception, as all Hi-MD recorders will show up as a USB mass storage device//