getid3_voc Class Reference
getID3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g // More...
Collaboration diagram for getid3_voc:
Public Member Functions | |
| getid3_voc (&$fd, &$ThisFileInfo) | |
| VOCcompressionTypeLookup ($index) | |
| VOCwFormatLookup ($index) | |
| VOCwFormatActualBitsPerSampleLookup ($index) | |
Detailed Description
getID3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g //
Definition at line 17 of file module.audio.voc.php.
Member Function Documentation
◆ getid3_voc()
| getid3_voc::getid3_voc | ( | & | $fd, |
| & | $ThisFileInfo | ||
| ) |
Definition at line 20 of file module.audio.voc.php.
20 {
21
22 $OriginalAVdataOffset = $ThisFileInfo['avdataoffset'];
23 fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
24 $VOCheader = fread($fd, 26);
25
26 if (substr($VOCheader, 0, 19) != 'Creative Voice File') {
27 $ThisFileInfo['error'][] = 'Expecting "Creative Voice File" at offset '.$ThisFileInfo['avdataoffset'].', found "'.substr($VOCheader, 0, 19).'"';
28 return false;
29 }
30
31 // shortcuts
32 $thisfile_audio = &$ThisFileInfo['audio'];
33 $ThisFileInfo['voc'] = array();
34 $thisfile_voc = &$ThisFileInfo['voc'];
35
36 $ThisFileInfo['fileformat'] = 'voc';
37 $thisfile_audio['dataformat'] = 'voc';
38 $thisfile_audio['bitrate_mode'] = 'cbr';
39 $thisfile_audio['lossless'] = true;
40 $thisfile_audio['channels'] = 1; // might be overriden below
41 $thisfile_audio['bits_per_sample'] = 8; // might be overriden below
42
43 // byte # Description
44 // ------ ------------------------------------------
45 // 00-12 'Creative Voice File'
46 // 13 1A (eof to abort printing of file)
47 // 14-15 Offset of first datablock in .voc file (std 1A 00 in Intel Notation)
48 // 16-17 Version number (minor,major) (VOC-HDR puts 0A 01)
49 // 18-19 2's Comp of Ver. # + 1234h (VOC-HDR puts 29 11)
50
51 $thisfile_voc['header']['datablock_offset'] = getid3_lib::LittleEndian2Int(substr($VOCheader, 20, 2));
52 $thisfile_voc['header']['minor_version'] = getid3_lib::LittleEndian2Int(substr($VOCheader, 22, 1));
53 $thisfile_voc['header']['major_version'] = getid3_lib::LittleEndian2Int(substr($VOCheader, 23, 1));
54
55 do {
56
57 $BlockOffset = ftell($fd);
58 $BlockData = fread($fd, 4);
59 $BlockType = ord($BlockData{0});
60 $BlockSize = getid3_lib::LittleEndian2Int(substr($BlockData, 1, 3));
61 $ThisBlock = array();
62
63 @$thisfile_voc['blocktypes'][$BlockType]++;
64 switch ($BlockType) {
65 case 0: // Terminator
66 // do nothing, we'll break out of the loop down below
67 break;
68
69 case 1: // Sound data
70 $BlockData .= fread($fd, 2);
71 if ($ThisFileInfo['avdataoffset'] <= $OriginalAVdataOffset) {
72 $ThisFileInfo['avdataoffset'] = ftell($fd);
73 }
74 fseek($fd, $BlockSize - 2, SEEK_CUR);
75
78
79 $ThisBlock['compression_name'] = $this->VOCcompressionTypeLookup($ThisBlock['compression_type']);
80 if ($ThisBlock['compression_type'] <= 3) {
81 $thisfile_voc['compressed_bits_per_sample'] = getid3_lib::CastAsInt(str_replace('-bit', '', $ThisBlock['compression_name']));
82 }
83
84 // Less accurate sample_rate calculation than the Extended block (#8) data (but better than nothing if Extended Block is not available)
85 if (empty($thisfile_audio['sample_rate'])) {
86 // SR byte = 256 - (1000000 / sample_rate)
87 $thisfile_audio['sample_rate'] = getid3_lib::trunc((1000000 / (256 - $ThisBlock['sample_rate_id'])) / $thisfile_audio['channels']);
88 }
89 break;
90
91 case 2: // Sound continue
92 case 3: // Silence
93 case 4: // Marker
94 case 6: // Repeat
95 case 7: // End repeat
96 // nothing useful, just skip
97 fseek($fd, $BlockSize, SEEK_CUR);
98 break;
99
100 case 8: // Extended
101 $BlockData .= fread($fd, 4);
102
103 //00-01 Time Constant:
104 // Mono: 65536 - (256000000 / sample_rate)
105 // Stereo: 65536 - (256000000 / (sample_rate * 2))
109
110 $thisfile_audio['channels'] = ($ThisBlock['stereo'] ? 2 : 1);
111 $thisfile_audio['sample_rate'] = getid3_lib::trunc((256000000 / (65536 - $ThisBlock['time_constant'])) / $thisfile_audio['channels']);
112 break;
113
114 case 9: // data block that supersedes blocks 1 and 8. Used for stereo, 16 bit
115 $BlockData .= fread($fd, 12);
116 if ($ThisFileInfo['avdataoffset'] <= $OriginalAVdataOffset) {
117 $ThisFileInfo['avdataoffset'] = ftell($fd);
118 }
119 fseek($fd, $BlockSize - 12, SEEK_CUR);
120
125
128 $thisfile_voc['compressed_bits_per_sample'] = $this->VOCwFormatActualBitsPerSampleLookup($ThisBlock['wFormat']);
129 }
130
131 $thisfile_audio['sample_rate'] = $ThisBlock['sample_rate'];
132 $thisfile_audio['bits_per_sample'] = $ThisBlock['bits_per_sample'];
133 $thisfile_audio['channels'] = $ThisBlock['channels'];
134 break;
135
136 default:
137 $ThisFileInfo['warning'][] = 'Unhandled block type "'.$BlockType.'" at offset '.$BlockOffset;
138 fseek($fd, $BlockSize, SEEK_CUR);
139 break;
140 }
141
142 if (!empty($ThisBlock)) {
143 $ThisBlock['block_offset'] = $BlockOffset;
144 $ThisBlock['block_size'] = $BlockSize;
145 $ThisBlock['block_type_id'] = $BlockType;
146 $thisfile_voc['blocks'][] = $ThisBlock;
147 }
148
149 } while (!feof($fd) && ($BlockType != 0));
150
151 // Terminator block doesn't have size field, so seek back 3 spaces
152 fseek($fd, -3, SEEK_CUR);
153
154 ksort($thisfile_voc['blocktypes']);
155
156 if (!empty($thisfile_voc['compressed_bits_per_sample'])) {
157 $ThisFileInfo['playtime_seconds'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / ($thisfile_voc['compressed_bits_per_sample'] * $thisfile_audio['channels'] * $thisfile_audio['sample_rate']);
158 $thisfile_audio['bitrate'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / $ThisFileInfo['playtime_seconds'];
159 }
160
161 return true;
162 }
VOCwFormatActualBitsPerSampleLookup($index)
Definition: module.audio.voc.php:188
VOCcompressionTypeLookup($index)
Definition: module.audio.voc.php:164
References getid3_lib\CastAsInt(), getid3_lib\LittleEndian2Int(), getid3_lib\trunc(), VOCcompressionTypeLookup(), VOCwFormatActualBitsPerSampleLookup(), and VOCwFormatLookup().
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◆ VOCcompressionTypeLookup()
| getid3_voc::VOCcompressionTypeLookup | ( | $index | ) |
Definition at line 164 of file module.audio.voc.php.
164 {
165 static $VOCcompressionTypeLookup = array(
166 0 => '8-bit',
167 1 => '4-bit',
168 2 => '2.6-bit',
169 3 => '2-bit'
170 );
171 return (isset($VOCcompressionTypeLookup[$index]) ? $VOCcompressionTypeLookup[$index] : 'Multi DAC ('.($index - 3).') channels');
172 }
Referenced by getid3_voc().
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◆ VOCwFormatActualBitsPerSampleLookup()
| getid3_voc::VOCwFormatActualBitsPerSampleLookup | ( | $index | ) |
Definition at line 188 of file module.audio.voc.php.
188 {
189 static $VOCwFormatLookup = array(
190 0x0000 => 8,
191 0x0001 => 4,
192 0x0002 => 3,
193 0x0003 => 2,
194 0x0004 => 16,
195 0x0006 => 8,
196 0x0007 => 8,
197 0x2000 => 4
198 );
199 return (isset($VOCwFormatLookup[$index]) ? $VOCwFormatLookup[$index] : false);
200 }
Referenced by getid3_voc().
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◆ VOCwFormatLookup()
| getid3_voc::VOCwFormatLookup | ( | $index | ) |
Definition at line 174 of file module.audio.voc.php.
174 {
175 static $VOCwFormatLookup = array(
176 0x0000 => '8-bit unsigned PCM',
177 0x0001 => 'Creative 8-bit to 4-bit ADPCM',
178 0x0002 => 'Creative 8-bit to 3-bit ADPCM',
179 0x0003 => 'Creative 8-bit to 2-bit ADPCM',
180 0x0004 => '16-bit signed PCM',
181 0x0006 => 'CCITT a-Law',
182 0x0007 => 'CCITT u-Law',
183 0x2000 => 'Creative 16-bit to 4-bit ADPCM'
184 );
185 return (isset($VOCwFormatLookup[$index]) ? $VOCwFormatLookup[$index] : false);
186 }
Referenced by getid3_voc().
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The documentation for this class was generated from the following file:
- Services/MediaObjects/getid3/getid3/module.audio.voc.php
