1 | # Copyright (c) 2005 Norman Timmler (inlet media e.K., Hamburg, Germany)
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2 | # All rights reserved.
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3 | #
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4 | # Redistribution and use in source and binary forms, with or without
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5 | # modification, are permitted provided that the following conditions
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6 | # are met:
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7 | # 1. Redistributions of source code must retain the above copyright
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8 | # notice, this list of conditions and the following disclaimer.
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9 | # 2. Redistributions in binary form must reproduce the above copyright
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10 | # notice, this list of conditions and the following disclaimer in the
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11 | # documentation and/or other materials provided with the distribution.
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12 | # 3. The name of the author may not be used to endorse or promote products
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13 | # derived from this software without specific prior written permission.
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14 | #
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15 | # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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16 | # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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17 | # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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18 | # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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19 | # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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20 | # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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21 | # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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22 | # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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23 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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24 | # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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25 |
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26 |
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27 | module FLV
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28 |
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29 | class FLVAudioTag < FLVTag
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30 |
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31 | UNCOMPRESSED = 0
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32 | ADPCM = 1
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33 | MP3 = 2
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34 | NELLYMOSER8KHZMONO = 5
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35 | NELLYMOSER = 6
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36 |
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37 | MONO = 0
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38 | STEREO = 1
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39 |
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40 | attr_reader :sound_format,
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41 | :sound_rate,
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42 | :sound_sample_size,
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43 | :sound_type
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44 |
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45 | def after_initialize(new_object)
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46 | @tag_type = AUDIO
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47 | read_header
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48 | end
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49 |
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50 | def name
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51 | 'Audio Tag'
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52 | end
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53 |
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54 | def read_header
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55 | data_stream = AMFStringBuffer.new(@data)
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56 | bit_sequence = data_stream.read__STRING(1).unpack('B8').to_s
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57 |
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58 | @sound_format = bit2uint(bit_sequence[0,4])
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59 | @sound_rate = case bit2uint(bit_sequence[4,2])
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60 | when 0
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61 | 5500
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62 | when 1
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63 | 11000
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64 | when 2
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65 | 22000
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66 | when 3
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67 | 44000
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68 | end
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69 | @sound_sample_size = case bit2uint(bit_sequence[6,1])
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70 | when 0
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71 | 8
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72 | when 1
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73 | 16
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74 | end
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75 | @sound_type = bit2uint(bit_sequence[7,1])
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76 |
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77 | # Nellymoser 8kHz mono special case
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78 | if @sound_format == NELLYMOSER8KHZMONO
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79 | @sound_rate = 8000
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80 | @sound_type = MONO
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81 | end
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82 | end
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83 |
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84 | def inspect
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85 | out = super
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86 | out << "sound_format: #{['Uncompressed', 'ADPCM', 'MP3', nil, nil, 'Nellymoser 8KHz mono', 'Nellymoser'][@sound_format]}"
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87 | out << "sound_rate: #{@sound_rate}"
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88 | out << "sound_sample_size: #{@sound_sample_size}"
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89 | out << "sound_type: #{['Mono', 'Stereo'][@sound_type]}"
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90 | out
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91 | end
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92 | end
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93 | end
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