FFV SPC analysis
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#!/usr/bin/python3 -i
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'''
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No license for now
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Search for potential BRR samples in an spc700 file.
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SPC-700 info
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0x00100 - 0x100FF contains RAM and is all we are interested in at present (64 KiB - 16bit address space)
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BRR info
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16bit audio samples.
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Blocks of 9 bytes.
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First byte is a header of form
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rrrr ffle
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Where rrrr is "range"/"granularity", rather the amount to leftshift the following samples by (0-12)
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ff is filter designation. Might be important later.
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l is loop flagbit. Normally 0 except on the last block.
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e is last chunk of sample. We'll use l and e to try to find series of chunks.
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Trailing 8 bytes are 16 4bit nibbles that make up the compressed samples.
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'''
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import sys
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from midiutil import MIDIFile
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from includes.helpers import indirect
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def generate_pointer_set(data):
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'''
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Scan through entire dataset and collect everything that could be a pointer.
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'''
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ptr_set = set()
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d_len = len(data)
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for i in range(d_len-1):
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x = int.from_bytes(data[i:i+2], 'little')
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if x < d_len-9:
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ptr_set.add(x)
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return ptr_set
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def analyse_sample(data, pointer):
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length = 0
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while data[pointer] & 1 == 0:
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length += 1
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pointer += 9
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if pointer > len(data)-9:
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return 0
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return length
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def decode_brr(data):
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range = data[0] >> 4
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filter_designation = (data[0] & 0x0C) >> 2
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loop = bool(data[0] & 0x02)
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end = bool(data[0] & 0x01)
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samples = []
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for i in range(8):
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samples.append((data[1+range] >> 4) << range)
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samples.append((data[1+range] & 0x0F) << range)
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return (samples, loop, end, filter_designation)
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def main(filename):
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global RAM, brr_dict
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with open(filename, 'rb') as file1:
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RAM = file1.read()[0x00100:0x10100]
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ptr_set = generate_pointer_set(RAM)
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blacklist = set() # Avoid re-entering sample chains
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brr_dict = {}
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for ptr in ptr_set:
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if ptr in blacklist:
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continue
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length = analyse_sample(RAM, ptr)
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if length > 49: # Ignore anything less than 50 blocks (800 samples) long
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brr_dict[ptr] = length
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for i in range(length):
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blacklist.add(ptr+((i+1)*9))
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for k in sorted(brr_dict.keys()):
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print('0x{:04x}: {:4d}'.format(k, brr_dict[k]))
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filename_jp = 'Final Fantasy V (Japan).sfc'
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def get_song_data(rom, id):
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lookup_offset = 0x043B97 + (id*3)
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offset = indirect(rom, lookup_offset, 3)-0xC00000
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bank = offset & 0xFF0000
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size = indirect(rom, offset)
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track_ptrs = [indirect(rom, offset+i)+bank for i in range(2, 22, 2)]
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if track_ptrs[0] != track_ptrs[1]:
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print('Master is not channel 1, interesting', track_ptrs)
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tracks = [rom[i:j] for i, j in zip(track_ptrs[1:-1], track_ptrs[2:])]
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#data = rom[offset+2:offset+2+size]
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return tracks
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class SPCParser:
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notes = [i for i in range(12)]
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durations = [4, 3, 2, 4/3, 1.5, 1, 2/3, 0.75, 0.5, 1/3, 0.25, 0.5/3, 0.125, 0.25/3, 0.0625]
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def __init__(self):
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self.control_codes = [
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(1, self._set_volume), # 0xD2
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(2, self._slide_volume), # 0xD3
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(1, self._set_pan), # 0xD4
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(2, self._slide_pan), # 0xD5
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(1, 'SomeSlide'), # 0xD6
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(3, 'Vibrato'), # 0xD7
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(0, 'VibratoOff'), # 0xD8
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(3, 'Tremolo'), # 0xD9
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(0, 'TremoloOff'), # 0xDA
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(2, 'PanLoop'), # 0xDB
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(0, 'PanLoopOff'), # 0xDC
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(1, 'Noise'), # 0xDD
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(0, 'NoiseOff'), # 0xDE
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(0, 'unk'), # 0xDF
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(0, 'unk'), # 0xE0
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(0, 'unk'), # 0xE1
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(0, 'EchoOn'), # 0xE2
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(0, 'EchoOff'), # 0xE3
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(1, self._set_octave), # 0xE4
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(0, self._inc_octave), # 0xE5
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(0, self._dec_octave), # 0xE6
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(1, self._set_transpose), # 0xE7
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(1, self._rel_transpose), # 0xE8
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(1, 'FineTune'), # 0xE9
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(1, self._set_instrument), # 0xEA
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(1, 'unk1'), # 0xEB
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(1, 'unk1'), # 0xEC
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(0, 'unk'), # 0xED
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(1, 'unk1'), # 0xEE
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(0, 'unk'), # 0xEF
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(1, self._start_loop), # 0xF0
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(0, self._end_loop), # 0xF1
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(0, self._end_channel), # 0xF2
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(1, self._set_tempo), # 0xF3
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(2, self._slide_tempo), # 0xF4
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(1, 'SetEchoVel'), # 0xF5
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(2, 'SlideEchoVel'), # 0xF6
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(2, 'unk2'), # 0xF7
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(1, 'SetGlobalVel'), # 0xF8
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(3, 'EndLoop2'), # 0xF9
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(0, 'unk'), # 0xFA
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(0, 'unk'), # 0xFB
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(0, self._end_channel), # 0xFC
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(0, self._end_channel), # 0xFD
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(0, self._end_channel), # 0xFE
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(0, self._end_channel), # 0xFF
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]
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def _set_instrument(self, instrument):
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self.m.addProgramChange(self.track, 0, self.time, instrument)
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def _set_volume(self, volume):
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self.m.addControllerEvent(self.track, 0, self.time, 7, volume//2) # 0-255 needs to be 0-127 for MIDI
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def _slide_volume(self, volume, time):
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# TODO slide
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self.m.addControllerEvent(self.track, 0, self.time, 7, volume//2) # 0-255 needs to be 0-127 for MIDI
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def _set_pan(self, pan):
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self.m.addControllerEvent(self.track, 0, self.time, 7, 127-(pan//2)) # SPC panning is reversed
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def _slide_pan(self, pan, time):
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# TODO slide
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self.m.addControllerEvent(self.track, 0, self.time, 7, 127-(pan//2))
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def _set_octave(self, octave):
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self.octave = octave
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def _inc_octave(self):
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self.octave += 1
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def _dec_octave(self):
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self.octave -= 1
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def _set_transpose(self, transpose):
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self.transpose = transpose
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def _rel_transpose(self, transpose):
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self.transpose += transpose
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def _end_channel(self):
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self.i = 0xFFFFFFFF
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def _set_tempo(self, tempo):
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self.m.addTempo(self.track, self.time, tempo)
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def _slide_tempo(self, time, tempo):
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# TODO slide
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self.m.addTempo(self.track, self.time, tempo)
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def _start_loop(self, repeats):
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print('Starting loop', repeats)
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self.loop_i = self.i
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self.repeats = repeats
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def _end_loop(self):
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print('Ending loop', self.repeats)
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if self.repeats > 0:
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self.i = self.loop_i
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self.repeats -= 1
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def parse(self, tracks):
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print('Parsing')
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self.m = MIDIFile(len(tracks))
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self.velocity = 100
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for track, t in enumerate(tracks):
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print('Creating track', track)
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self.track = track
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self.time = 0
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self.octave = 5
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self.transpose = 0
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self.repeats = 0
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self.loop_i = 0
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self.i = 0
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while self.i < len(t):
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t1 = t[self.i]
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self.i += 1
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if t1 < 0xD2:
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duration = self.durations[t1%15]
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t2 = t1 // 15
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if t2<12: # Others are rests
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note = self.notes[t2]+(12*self.octave)+self.transpose
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self.m.addNote(track, 0, note, self.time, duration, self.velocity)
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self.time += duration
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else:
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n, callback = self.control_codes[t1-0xD2]
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args = [t[self.i+j] for j in range(n)]
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self.i += n
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if callable(callback):
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callback(*args)
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else:
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print(callback, '0x{:02x}'.format(t1))
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return self.m
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def make_midi_file(tracks, filename='test.mid'):
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m = SPCParser().parse(tracks)
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with open(filename, 'wb') as file:
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m.writeFile(file)
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def read_rom(filename=filename_jp):
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with open(filename, 'rb') as file:
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f = file.read()
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return f
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if __name__ == '__main__':
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main(sys.argv[1])
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