mirror of
https://github.com/iluvcapra/wavinfo.git
synced 2026-01-01 09:20:40 +00:00
43 lines
1.3 KiB
Python
43 lines
1.3 KiB
Python
import struct
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from collections import namedtuple
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from . import riff_parser
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RF64Context = namedtuple('RF64Context','sample_count bigchunk_table')
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def parse_rf64(stream, signature = b'RF64') -> RF64Context:
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start = stream.tell()
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assert( stream.read(4) == b'WAVE' )
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ds64_chunk = riff_parser.parse_chunk(stream)
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assert type(ds64_chunk) is riff_parser.ChunkDescriptor, \
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f"Expected ds64 chunk here, found {type(ds64_chunk)}"
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ds64_field_spec = "<QQQI"
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ds64_fields_size = struct.calcsize(ds64_field_spec)
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assert(ds64_chunk.ident == b'ds64')
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ds64_data = ds64_chunk.read_data(stream)
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assert(len(ds64_data) >= ds64_fields_size)
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riff_size, data_size, sample_count, length_lookup_table = struct.unpack(
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ds64_field_spec, ds64_data[0:ds64_fields_size])
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bigchunk_table = {}
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chunksize64format = "<4sL"
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# chunksize64size = struct.calcsize(chunksize64format)
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for _ in range(length_lookup_table):
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bigname, bigsize = struct.unpack_from(chunksize64format, ds64_data,
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offset= ds64_fields_size)
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bigchunk_table[bigname] = bigsize
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bigchunk_table[b'data'] = data_size
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bigchunk_table[signature] = riff_size
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stream.seek(start, 0)
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return RF64Context( sample_count=sample_count,
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bigchunk_table=bigchunk_table)
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