mirror of
https://github.com/iluvcapra/wavinfo.git
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112 lines
3.7 KiB
Python
112 lines
3.7 KiB
Python
import struct
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from typing import Tuple, NamedTuple, List
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class WaveSmplLoop(NamedTuple):
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ident: int
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loop_type: int
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start: int
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end: int
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detune_cents: int
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repetition_count: int
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def loop_type_desc(self):
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if self.loop_type == 0:
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return 'FORWARD'
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elif self.loop_type == 1:
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return 'FORWARD_BACKWARD'
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elif self.loop_type == 2:
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return 'BACKWARD'
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elif 3 <= self.loop_type <= 31:
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return 'RESERVED'
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else:
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return 'VENDOR'
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def to_dict(self):
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return {
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'ident': self.ident,
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'loop_type': self.loop_type,
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'loop_type_description': self.loop_type_desc(),
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'start_samples': self.start,
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'end_samples': self.end,
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'detune_cents': self.detune_cents,
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'repetition_count': self.repetition_count,
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}
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class WavSmplReader:
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def __init__(self, smpl_data: bytes):
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"""
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Read sampler metadata from smpl chunk.
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"""
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header_field_fmt = "<IIIIiIbbbbII"
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loop_field_fmt = "<IIIIII"
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header_size = struct.calcsize(header_field_fmt)
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loop_size = struct.calcsize(loop_field_fmt)
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unpacked_data = struct.unpack(header_field_fmt,
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smpl_data[0:header_size])
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#: The MIDI Manufacturer's Association code for the sampler
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#: manufactuer, or 0 if not specific.
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self.manufacturer: int = unpacked_data[0]
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#: The manufacturer-assigned code for their specific sampler model, or
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#: 0 if not specific.
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self.product: int = unpacked_data[1]
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#: The number of nanoseconds in one audio frame.
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self.sample_period_ns: int = unpacked_data[2]
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#: The MIDI note number for the loops in this sample
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self.midi_note: int = unpacked_data[3]
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#: The number of semitones above the MIDI note the loops tune for.
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self.midi_pitch_detune_cents: int = unpacked_data[4]
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#: SMPTE timecode format, one of (0, 24, 25, 29, 30)
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self.smpte_format: int = unpacked_data[5]
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#: The SMPTE offset to apply, as a tuple of four ints representing
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#: hh, mm, ss, ff
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self.smpte_offset: Tuple[int, int, int, int] = unpacked_data[6:10]
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loop_count = unpacked_data[10]
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sampler_udata_length = unpacked_data[11]
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#: List of loops in the file.
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self.sample_loops: List[WaveSmplLoop] = []
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loop_buffer = smpl_data[header_size:
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header_size + loop_size * loop_count]
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for unpacked_loop in struct.iter_unpack(loop_field_fmt, loop_buffer):
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self.sample_loops.append(WaveSmplLoop(
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ident=unpacked_loop[0],
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loop_type=unpacked_loop[1],
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start=unpacked_loop[2],
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end=unpacked_loop[3],
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detune_cents=unpacked_loop[4],
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repetition_count=unpacked_loop[5]))
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#: Sampler-specific user data.
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self.sampler_udata: bytes = smpl_data[
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header_size + loop_size * loop_count:
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header_size + loop_size * loop_count + sampler_udata_length]
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def to_dict(self):
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return {
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'manufactuer': self.manufacturer,
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'product': self.product,
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'sample_period_ns': self.sample_period_ns,
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'midi_note': self.midi_note,
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'midi_pitch_detune_cents': self.midi_pitch_detune_cents,
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'smpte_format': self.smpte_format,
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'smpte_offset': "%02i:%02i:%02i:%02i" % self.smpte_offset,
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'loops': [x.to_dict() for x in self.sample_loops],
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'sampler_user_data': self.sampler_udata,
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}
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