Sampled sound format IFF FORM "SAMP" Sampled Sound Date: Dec 3,1989 From: Jim Fiore and Jeff Glatt, dissidents The form "SAMP" is a file format used to store sampled sound data in some ways like the current standard, "8SVX". Unlike "8SVX", this new format is not restricted to 8 bit sample data. There can be more than one waveform per octave, and the lengths of different waveforms do not have to be factors of 2. In fact, the lengths (waveform size) and playback mapping (which musical notes each waveform will "play") are independently determined for each wave- form. Furthermore, this format takes into account the MIDI sample dump stan- dard (the defacto standard for musical sample storage), while also incorpo- rating the ability to store Amiga specific info (for example, the sample data that might be sent to an audio channel which is modulating another channel). Although this form can be used to store "sound effects" (typically oneShot sounds played at a set pitch), it is primarily intended to correct the many deficiencies of the "8SVX" form in regards to musical sampling. Because the emphasis is on musical sampling, this format relies on the MIDI (Musical Instrument Digital Interface) method of describing "sound events" as does virtually all currently manufactured, musical samplers. In addition, it at- tempts to incorporate features found on many professional music samplers, in anticipation that future Amiga models will implement 16 bit sampling, and thus be able to achieve this level of performance. Because this format is more complex than "8SVX", programming examples to demonstrate the use of this format have been included in both C and assembly. Also, a library of func- tions to read and write SAMP files is available, with example applications. SEMANTICS: When MIDI literature talks about a sample, usually it means a collection of many sample points that make up what we call a "wave". Similarities and Differences from the 8SVX Form The SAMP Header The MHDR Chunk The NAME Chunk The BODY Chunk Structure of an Individual Sample Point The Waveheader Explained MIDI Velocity vs. Amiga Channel Volume An EGpoint (Envelope Generator) Additional User Data Section Converting Midi Sample Dump to SAMP Interpreting the Playmode Making A Transpose Table Making the Velocity Table The Instrument Type The Order of the Chunks Filename Conventions Why Does Anyone Need Such a Complicated File?
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