1 | <?php |
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2 | // +----------------------------------------------------------------------+ |
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3 | // | PHP version 5 | |
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4 | // +----------------------------------------------------------------------+ |
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5 | // | Copyright (c) 2002-2006 James Heinrich, Allan Hansen | |
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6 | // +----------------------------------------------------------------------+ |
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7 | // | This source file is subject to version 2 of the GPL license, | |
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8 | // | that is bundled with this package in the file license.txt and is | |
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9 | // | available through the world-wide-web at the following url: | |
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10 | // | http://www.gnu.org/copyleft/gpl.html | |
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11 | // +----------------------------------------------------------------------+ |
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12 | // | getID3() - http://getid3.sourceforge.net or http://www.getid3.org | |
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13 | // +----------------------------------------------------------------------+ |
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14 | // | Authors: James Heinrich <infoØgetid3*org> | |
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15 | // | Allan Hansen <ahØartemis*dk> | |
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16 | // +----------------------------------------------------------------------+ |
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17 | // | module.audio.mpc_old.php | |
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18 | // | Module for analyzing Musepack/MPEG+ Audio files - SV4-SV6 | |
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19 | // | dependencies: NONE | |
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20 | // +----------------------------------------------------------------------+ |
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21 | // |
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22 | // $Id: module.audio.mpc_old.php 3318 2009-05-20 21:54:10Z vdigital $ |
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23 | |
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24 | |
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25 | |
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26 | class getid3_mpc_old extends getid3_handler |
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27 | { |
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28 | |
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29 | public function Analyze() { |
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30 | |
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31 | $getid3 = $this->getid3; |
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32 | |
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33 | // http://www.uni-jena.de/~pfk/mpp/sv8/header.html |
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34 | |
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35 | $getid3->info['mpc']['header'] = array (); |
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36 | $info_mpc_header = &$getid3->info['mpc']['header']; |
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37 | |
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38 | $getid3->info['fileformat'] = 'mpc'; |
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39 | $getid3->info['audio']['dataformat'] = 'mpc'; |
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40 | $getid3->info['audio']['bitrate_mode'] = 'vbr'; |
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41 | $getid3->info['audio']['channels'] = 2; // the format appears to be hardcoded for stereo only |
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42 | $getid3->info['audio']['lossless'] = false; |
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43 | |
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44 | fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET); |
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45 | |
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46 | $info_mpc_header['size'] = 8; |
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47 | $getid3->info['avdataoffset'] += $info_mpc_header['size']; |
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48 | |
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49 | $mpc_header_data = fread($getid3->fp, $info_mpc_header['size']); |
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50 | |
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51 | |
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52 | // Most of this code adapted from Jurgen Faul's MPEGplus source code - thanks Jurgen! :) |
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53 | $header_dword[0] = getid3_lib::LittleEndian2Int(substr($mpc_header_data, 0, 4)); |
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54 | $header_dword[1] = getid3_lib::LittleEndian2Int(substr($mpc_header_data, 4, 4)); |
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55 | |
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56 | |
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57 | // DDDD DDDD CCCC CCCC BBBB BBBB AAAA AAAA |
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58 | // aaaa aaaa abcd dddd dddd deee eeff ffff |
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59 | // |
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60 | // a = bitrate = anything |
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61 | // b = IS = anything |
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62 | // c = MS = anything |
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63 | // d = streamversion = 0000000004 or 0000000005 or 0000000006 |
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64 | // e = maxband = anything |
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65 | // f = blocksize = 000001 for SV5+, anything(?) for SV4 |
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66 | |
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67 | $info_mpc_header['target_bitrate'] = (($header_dword[0] & 0xFF800000) >> 23); |
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68 | $info_mpc_header['intensity_stereo'] = (bool)(($header_dword[0] & 0x00400000) >> 22); |
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69 | $info_mpc_header['mid-side_stereo'] = (bool)(($header_dword[0] & 0x00200000) >> 21); |
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70 | $info_mpc_header['stream_major_version'] = ($header_dword[0] & 0x001FF800) >> 11; |
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71 | $info_mpc_header['stream_minor_version'] = 0; |
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72 | $info_mpc_header['max_band'] = ($header_dword[0] & 0x000007C0) >> 6; // related to lowpass frequency, not sure how it translates exactly |
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73 | $info_mpc_header['block_size'] = ($header_dword[0] & 0x0000003F); |
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74 | |
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75 | switch ($info_mpc_header['stream_major_version']) { |
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76 | case 4: |
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77 | $info_mpc_header['frame_count'] = ($header_dword[1] >> 16); |
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78 | break; |
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79 | case 5: |
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80 | case 6: |
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81 | $info_mpc_header['frame_count'] = $header_dword[1]; |
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82 | break; |
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83 | |
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84 | default: |
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85 | throw new getid3_exception('Expecting 4, 5 or 6 in version field, found '.$info_mpc_header['stream_major_version'].' instead'); |
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86 | } |
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87 | |
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88 | if (($info_mpc_header['stream_major_version'] > 4) && ($info_mpc_header['block_size'] != 1)) { |
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89 | $getid3->warning('Block size expected to be 1, actual value found: '.$info_mpc_header['block_size']); |
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90 | } |
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91 | |
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92 | $info_mpc_header['sample_rate'] = $getid3->info['audio']['sample_rate'] = 44100; // AB: used by all files up to SV7 |
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93 | $info_mpc_header['samples'] = $info_mpc_header['frame_count'] * 1152 * $getid3->info['audio']['channels']; |
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94 | |
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95 | $getid3->info['audio']['bitrate_mode'] = $info_mpc_header['target_bitrate'] == 0 ? 'vbr' : 'cbr'; |
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96 | |
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97 | $getid3->info['mpc']['bitrate'] = ($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8 * 44100 / $info_mpc_header['frame_count'] / 1152; |
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98 | $getid3->info['audio']['bitrate'] = $getid3->info['mpc']['bitrate']; |
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99 | $getid3->info['audio']['encoder'] = 'SV'.$info_mpc_header['stream_major_version']; |
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100 | |
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101 | return true; |
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102 | } |
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103 | |
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104 | } |
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105 | |
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106 | |
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107 | ?> |
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