Files
wavinfo/wavinfo/wave_bext_reader.py
2019-01-01 23:50:46 -08:00

90 lines
3.3 KiB
Python

import struct
class WavBextReader:
def __init__(self,bext_data,encoding):
# description[256]
# originator[32]
# originatorref[32]
# originatordate[10] "YYYY:MM:DD"
# originatortime[8] "HH:MM:SS"
# lowtimeref U32
# hightimeref U32
# version U16
#
# V1 field
# umid[64]
#
# V2 fields
# loudnessvalue S16 (in LUFS*100)
# loudnessrange S16 (in LUFS*100)
# maxtruepeak S16 (in dbTB*100)
# maxmomentaryloudness S16 (LUFS*100)
# maxshorttermloudness S16 (LUFS*100)
#
# reserved[180]
# codinghistory []
if bext_data is None:
return None
packstring = "<256s"+ "32s" + "32s" + "10s" + "8s" + "QH" + "64s" + "hhhhh" + "180s"
rest_starts = struct.calcsize(packstring)
unpacked = struct.unpack(packstring, bext_data[:rest_starts])
def sanatize_bytes(bytes):
first_null = next( (index for index, byte in enumerate(bytes) if byte == 0 ), None )
if first_null is not None:
trimmed = bytes[:first_null]
else:
trimmed = bytes
decoded = trimmed.decode(encoding)
return decoded
bext_version = unpacked[6]
if bext_version > 0:
self.umid = unpacked[6]
else:
self.umid = None
if bext_version > 1:
self.loudness_value = unpacked[8] / 100.0,
self.loudness_range = unpacked[9] / 100.0
self.max_true_peak = unpacked[10] / 100.0
self.max_momentary_loudness = unpacked[11] / 100.0
self.max_shortterm_loudness = unpacked[12] / 100.0
else:
self.loudness_value = None
self.loudness_range = None
self.max_true_peak = None
self.max_momentary_loudness = None
self.max_shortterm_loudness = None
self.description = sanatize_bytes(unpacked[0])
self.originator = sanatize_bytes(unpacked[1])
self.originator_ref = sanatize_bytes(unpacked[2])
self.originator_date = sanatize_bytes(unpacked[3])
self.originator_time = sanatize_bytes(unpacked[4])
self.time_reference = unpacked[5]
self.version = unpacked[6]
self.coding_history = sanatize_bytes(bext_data[rest_starts:])
def to_dict(self):
return {'description': self.description,
'originator': self.originator,
'originator_ref': self.originator_ref,
'originator_date': self.originator_date,
'originator_time': self.originator_time,
'time_reference': self.time_reference,
'version': self.version,
'coding_history': self.coding_history,
'loudness_value': self.loudness_value,
'loudness_range': self.loudness_range,
'max_true_peak': self.max_true_peak,
'max_momentary_loudness': self.max_momentary_loudness,
'max_shortterm_loudness': self.max_shortterm_loudness
}