pydmcsid 0.1.0

Pure-Python reader and player for DMC (Demo Music Creator) SID tunes

pydmcsid

Pure-Python reader and player for DMC (Demo Music Creator) SID tunes — the C64 player by Brian/Graffity ("-PLAYER (C) BRIAN/GRAFFITY!").

A DMC .sid is the player binary plus the per-tune song data resident in the same image. pydmcsid loads the image, locates the per-tune table bases from the player code operands (no baked addresses — a differently-sized tune relocates its tables), and runs a faithful integer transcription of the 6502 play routine, exposing the per-frame SID register writes.

Usage

import pydmcsid

song = pydmcsid.read("tune.sid")
for w in pydmcsid.iter_register_writes(song, max_frames=50 * 60):
    print(w.clock, w.reg, w.val)   # absolute CPU cycle, $D4xx reg offset, value

iter_register_writes follows the shared py* register-log convention (pygoattracker / pymusicassembler): one RegWrite(clock, reg, val) per SID write, frames cycles_per_frame apart. The DMC player emits one tight write burst per VBI play call.

What it models

Tempo divider, per-voice orderlist walk (transpose / loop / stop), pattern walk (note / instrument-select / duration / effect / gate), stride-11 instrument records driving PW init + a 16-bit PW sweep, the $FF-arp wavetable, triangle vibrato, glide, the pitch-slide effect and a 6-step filter sweep, the hard-restart window, and the final per-voice frequency compose. Transcribed from the DMC disassembly.

License

Apache-2.0.