89 lines
3.2 KiB
Python
89 lines
3.2 KiB
Python
"""
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AU audio file parser
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Author: Victor Stinner
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Creation: 12 july 2006
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"""
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from lib.hachoir_parser import Parser
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from lib.hachoir_core.field import UInt32, Enum, String, RawBytes
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from lib.hachoir_core.endian import BIG_ENDIAN
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from lib.hachoir_core.text_handler import displayHandler, filesizeHandler
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from lib.hachoir_core.tools import createDict, humanFrequency
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class AuFile(Parser):
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PARSER_TAGS = {
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"id": "sun_next_snd",
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"category": "audio",
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"file_ext": ("au", "snd"),
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"mime": (u"audio/basic",),
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"min_size": 24*8,
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"magic": ((".snd", 0),),
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"description": "Sun/NeXT audio"
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}
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endian = BIG_ENDIAN
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CODEC_INFO = {
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1: (8, u"8-bit ISDN u-law"),
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2: (8, u"8-bit linear PCM"),
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3: (16, u"16-bit linear PCM"),
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4: (24, u"24-bit linear PCM"),
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5: (32, u"32-bit linear PCM"),
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6: (32, u"32-bit IEEE floating point"),
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7: (64, u"64-bit IEEE floating point"),
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8: (None, u"Fragmented sample data"),
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9: (None, u"DSP program"),
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10: (8, u"8-bit fixed point"),
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11: (16, u"16-bit fixed point"),
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12: (24, u"24-bit fixed point"),
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13: (32, u"32-bit fixed point"),
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18: (16, u"16-bit linear with emphasis"),
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19: (16, u"16-bit linear compressed"),
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20: (16, u"16-bit linear with emphasis and compression"),
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21: (None, u"Music kit DSP commands"),
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23: (None, u"4-bit ISDN u-law compressed (CCITT G.721 ADPCM)"),
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24: (None, u"ITU-T G.722 ADPCM"),
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25: (None, u"ITU-T G.723 3-bit ADPCM"),
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26: (None, u"ITU-T G.723 5-bit ADPCM"),
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27: (8, u"8-bit ISDN A-law"),
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}
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# Create bit rate and codec name dictionnaries
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BITS_PER_SAMPLE = createDict(CODEC_INFO, 0)
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CODEC_NAME = createDict(CODEC_INFO, 1)
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VALID_NB_CHANNEL = set((1,2)) # FIXME: 4, 5, 7, 8 channels are supported?
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def validate(self):
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if self.stream.readBytes(0, 4) != ".snd":
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return "Wrong file signature"
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if self["channels"].value not in self.VALID_NB_CHANNEL:
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return "Invalid number of channel"
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return True
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def getBitsPerSample(self):
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"""
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Get bit rate (number of bit per sample per channel),
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may returns None if you unable to compute it.
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"""
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return self.BITS_PER_SAMPLE.get(self["codec"].value)
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def createFields(self):
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yield String(self, "signature", 4, 'Format signature (".snd")', charset="ASCII")
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yield UInt32(self, "data_ofs", "Data offset")
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yield filesizeHandler(UInt32(self, "data_size", "Data size"))
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yield Enum(UInt32(self, "codec", "Audio codec"), self.CODEC_NAME)
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yield displayHandler(UInt32(self, "sample_rate", "Number of samples/second"), humanFrequency)
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yield UInt32(self, "channels", "Number of interleaved channels")
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size = self["data_ofs"].value - self.current_size // 8
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if 0 < size:
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yield String(self, "info", size, "Information", strip=" \0", charset="ISO-8859-1")
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size = min(self["data_size"].value, (self.size - self.current_size) // 8)
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yield RawBytes(self, "audio_data", size, "Audio data")
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def createContentSize(self):
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return (self["data_ofs"].value + self["data_size"].value) * 8
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