mirror of
https://github.com/iluvcapra/wavinfo.git
synced 2025-12-31 08:50:41 +00:00
90 lines
3.8 KiB
Python
90 lines
3.8 KiB
Python
import struct
|
|
import binascii
|
|
from .umid_parser import UMIDParser
|
|
|
|
|
|
class WavBextReader:
|
|
def __init__(self, bext_data, encoding):
|
|
"""
|
|
Read Broadcast-WAV extended metadata.
|
|
:param bext_data: The bytes-like data.
|
|
:param encoding: The encoding to use when decoding the text fields of the
|
|
BEXT metadata scope. According to EBU Rec 3285 this shall be ASCII.
|
|
"""
|
|
packstring = "<256s" + "32s" + "32s" + "10s" + "8s" + "QH" + "64s" + "hhhhh" + "180s"
|
|
|
|
rest_starts = struct.calcsize(packstring)
|
|
unpacked = struct.unpack(packstring, bext_data[:rest_starts])
|
|
|
|
def sanitize_bytes(b):
|
|
first_null = next((index for index, byte in enumerate(b) if byte == 0), None)
|
|
trimmed = b if first_null is None else b[:first_null]
|
|
decoded = trimmed.decode(encoding)
|
|
return decoded
|
|
|
|
#: Description. A free-text field up to 256 characters long.
|
|
self.description = sanitize_bytes(unpacked[0])
|
|
#: Originator. Usually the name of the encoding application, sometimes
|
|
#: a artist name.
|
|
self.originator = sanitize_bytes(unpacked[1])
|
|
#: A unique identifier for the file, a serial number.
|
|
self.originator_ref = sanitize_bytes(unpacked[2])
|
|
#: Date of the recording, in the format YYY-MM-DD
|
|
self.originator_date = sanitize_bytes(unpacked[3])
|
|
#: Time of the recording, in the format HH:MM:SS.
|
|
self.originator_time = sanitize_bytes(unpacked[4])
|
|
#: The sample offset of the start of the file relative to an
|
|
#: epoch, usually midnight the day of the recording.
|
|
self.time_reference = unpacked[5]
|
|
#: A variable-length text field containing a list of processes and
|
|
#: and conversions performed on the file.
|
|
self.coding_history = sanitize_bytes(bext_data[rest_starts:])
|
|
#: BEXT version.
|
|
self.version = unpacked[6]
|
|
#: SMPTE 330M UMID of this audio file, 64 bytes are allocated though the UMID
|
|
#: may only be 32 bytes long.
|
|
self.umid = None
|
|
#: EBU R128 Integrated loudness, in LUFS.
|
|
self.loudness_value = None
|
|
#: EBU R128 Loudness rante, in LUFS.
|
|
self.loudness_range = None
|
|
#: True peak level, in dBFS TP
|
|
self.max_true_peak = None
|
|
#: EBU R128 Maximum momentary loudness, in LUFS
|
|
self.max_momentary_loudness = None
|
|
#: EBU R128 Maximum short-term loudness, in LUFS.
|
|
self.max_shortterm_loudness = None
|
|
|
|
if self.version > 0:
|
|
self.umid = unpacked[7]
|
|
|
|
if self.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
|
|
|
|
def to_dict(self):
|
|
if self.umid is not None:
|
|
umid_parsed = UMIDParser(self.umid)
|
|
umid_str = umid_parsed.basic_umid_to_str()
|
|
else:
|
|
umid_str = None
|
|
|
|
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,
|
|
'umid': umid_str,
|
|
'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
|
|
}
|