----------------------------------- *** Flowerpower's ADPCM package *** ----------------------------------- This software package is in the public domain. Do with it whatever you want. The files in this package will enable you to * rip CD tracks using a Toshiba Drive (+) and store them in ADPCM format * convert RAW PCM and AIFF (e.g. MPEG audio) streams to ADPCM format (++) * play these audio tracks using DeliTracker like ordinary sound modules * play the files using a stand-alone player, requiring little memory * convert any known sample format (DataTypes!) to ADPCM format * an ADPCM datatype is included for use with e.g. MultiView (+) (some IDE and ATAPI drives now also work because their driver software emulates the SCSI command set. Ask your local dealer.) (++) MPega V2.9 or 3.x by Stephane Tavenard required for decoding the MPeg Audio streams. Why this Program was Created ---------------------------- At a computer meeting in Thanning, Germany, a friend of mine proposed me to write a program for ripping songs off a CD and saving them as a kind of "sound module" for use with DeliTracker, taking away as little space as possible. I used my ADPCM compression routines that I had coded some years ago. The bet was to code this in 2 and a half hours, but no chance ;-) Some days later this program was finally finished. What is ADPCM? -------------- ADPCM is a lossy sample compression method allowing a very high compression ratio. The drawback of this compression technique is an audible noise level, but this is still acceptable. Example ------- You can store a 3 minute music track ("Cotton Eye Joe") in 982999 bytes. This can be further reduced by about 10% using an ordinary packer. You can listen to this audio track with DeliTracker just like an ordinary sound module. Quality Issues -------------- The samples are stored in MONO. The quality of ADPCM2 is like a poor tape recording. Ratio 1:4 (25%) The quality of ADPCM3 is like a good tape recording. Ratio 3:8 (37%) The Algorithm ------------- The algorithm is taken from the ZyXel ADPCM compression methods for voice files and was implemented as a fast assembly routine. The Sample Format ----------------- The sample format is highly primitive: 6 Bytes: identifier: "ADPCM2" or "ADPCM3" 4 Bytes: the replay frequency in Hz as ULONG n Bytes: cruched sample data in ADPCM format Program History --------------- Release 1: initial AmiNet release on 27-Apr-95 Release 2: release on Aminet 5-Oct-95 - all programs got a version string - fixed makefile of ADPCM datatype - PlayADPCM slightly updated (->V1.1) - reduced chip buffer size for the DeliPlayer to 1K (->V1.1) - The DeliPlayer got a realtime loader and a NotePlayer interface (->V1.2) - the ADPCM datatype descriptor was buggy (marked as picture!) - improved X2ADPCM's datatypes error output (->V1.1) - I got a new address and phone number! Release 3: release on Aminet 22-Oct-95 - small fixes to the DeliPlayer's Noteplayer interface - CDripper got NumTracks option, Maximize and Boost abilities (->V1.1) Release 4: release on Aminet 30-Jul-97 - added the Hifi2ADPCM program. The Author ---------- Christian Buchner Steinbergstraße 2 82110 Germering Germany Tel.: +49-89-849868 EMAIL: flowerp@eikon.e-technik.tu-muenchen.de on irc #amiga and #amigager // \X/ Flowerpower