ATRAC Codec Notes
This page has my notes about ATRAC codecs.
"ATRAC" as it exists in minidisc refers to a couple separate codecs.
- ATRAC1, also called "SP", or on the machines as "Stereo" and "Mono" is the original version of the ATRAC codec deployed in 1992
- There are several versions of ATRAC1, and different vendors had their own implementations, such as Sony's ATRAC1 Type-R and Panasonic's HDES, Sharp had its own numbering
- "Many" but not all Type-R machines also have MDLP, examples of non-MDLP Type-R machines include the MXD-D3, MDS-JE530/630 and JB930, as well as the MDS-DL1
- Some documentation will say "ATRAC version" and then a number — My recommendation in the mdoern context is to write this as "ATRAC1 version #" - for example, you could note that the Sony MZ-R55 uses an ATRAC1 v4.0 codec
- ATRAC3 is a new codec that is used in some of Sony's various file-based players, as well as in MDLP hardware
- All MDLP hardware uses a Sony codec block for ATRAC3, even if combined with a third party ATRAC1, so you can get a Panasonic machine with HDES ATRAC1 and Sony's own ATRAC3 codec
- Some Sony hardware has ATRAC1 v4.5 paired with MDLP
- Most Type-R hardware has MDLP, but not all of it does, and, Type-R itself only refers to the SP/ATRAC1 processing
- Type-S is the last new MD-MDLP-era codec, however the only change in the codec is that Type-S has improved MDLP playback
- When using NetMD, the computer software does the actual MDLP encoding
- As such, which specific program and encoder is used makes a difference, if you're using Web MiniDisc, consider using the remote encoder for best results
- In MiniDisc, there are two modes:
- LP2 at 132 kilobits per second
- LP4 at 66 kilobits per second
- There is a third mode of 105 kilobits per second, if used in OpenMG software and written to minidisc, it'll fill the space of LP2 data and be given extra padding
- ATRAC3plus is a newer codec, closely related to but incompatible with ATRAC3, used in some of Sony's newer file-based players as well as HiMD hardware
- HiMD hardware sports two modes:
- HiSP at 256-kilobits per second
- HiLP at 64-kilobits per second
- Most HiMD models can play all AT3+ modes Sony will allow you to transfer
- There is no known differences in the HiMD codec hardware, across the three different generations
- HiMD hardware all otherwise conforms to the Type-S specification, for MD-MDLP discs
- HiMD hardware sports two modes: