MDLP, or MiniDisc Long Play, is a recent addition (it was introduced on the Sony MZ-R900 in 2000) to the MD feature list that increases the amount of music that can be stored on a MiniDisc. MDLP uses the newly-developed ATRAC3 codec at lower bitrates (132kbps and 66kbps for LP2 and LP4 respectively) than normal MD recordings (which uses ATRAC1, a different encoder). Sound quality is said to be comparable to MP3 at equivalent bitrates (I haven't received my Sony MZ-N1 so I can't comment personally).
The list of recorders and players that can read/write MDLP tracks is growing all the time. Here is a list of all the players/recorders that can read/write MDLP tracks in alphabetical order.
CD/MD Deck Recorders:
- Marantz CM6200
- Onkyo FR-V77
- Sony MXD-D40
- Sony MXD-D5C
Portable Players:
- Aiwa AM-HX100
- Aiwa AM-HX150
- Aiwa AM-HX200
- Aiwa AM-HX300
- Aiwa AM-HX400
- JVC XM-P2000
- JVC XM-PX50
- JVC XM-PX501
- JVC XM-PX601
- JVC XM-PX70
- JVC XM-ZX5
- Kenwood DMC-M55
- Kenwood DMC-P33
- Kenwood DMC-P55
- Panasonic SJ-MJ10
- Panasonic SJ-MJ50
- Panasonic SJ-MJ78
- Panasonic SJ-MJ90
- Sharp MD-ST70
- Sharp MD-ST77
- Sharp MD-ST700
- Sharp MD-ST770
- Sharp MD-ST800
- Sharp MD-ST880
- Sony MZ-E500
- Sony MZ-E501
- Sony MZ-E600
- Sony MZ-E606W
- Sony MZ-E700
- Sony MZ-E707
- Sony MZ-E900
- Sony MZ-E909
Portable Recorders:
- Aiwa AM-F90 (clone of Sony MZ-R900)
- JVC XM-R700
- Kenwood DMC-M7R
- Panasonic SJ-MR200
- Panasonic SJ-MR220
- Panasonic SJ-MR250
- Sharp IM-MT880
- Sharp MD-MT170
- Sharp MD-MT180
- Sharp MD-MT190
- Sharp MD-MT200
- Sharp MD-MT77
- Sharp MD-MT770
- Sharp MD-MT877
- Sharp MD-MT88
- Sharp MD-MT888
- Sharp MD-MT89
- Sharp MD-MT90
- Sony MZ-B100
- Sony MZ-G750
- Sony MZ-G755
- Sony MZ-N505
- Sony MZ-N707
- Sony MZ-N1 (first portable recorder with NetMD)
- Sony MZ-R500
- Sony MZ-R501
- Sony MZ-R700
- Sony MZ-R701
- Sony MZ-R900 (first portable recorder with MDLP)
- Sony MZ-R909 (first portable recorder with ATRAC1 Type-R DSP)
- Sony MZ-R910
- Sony MZ-S1 (first "Sports" portable recorder)
Deck Recorders:
- Sony MDS-JA333S
- Sony MDS-JB940
- Sony MDS-JE440
- Sony MDS-JE470
- Sony MDS-JE480
- Sony MDS-JE640
- Sony MDS-JE770
- Sony MDS-JE780
- Sony MDS-JB980 (first deck recorder with ATRAC1 Type-S DSP)
- Sony MDS-LSA1
- Sony MDS-NT1 (first deck recorder with NetMD)
- Sony MDS-PC3
- Sony MDS-S50
Sources:
Minidisc.org - http://www.minidisc.org