getID3() by James Heinrich <info@getid3.org> // More...
Public Member Functions | |
| getid3_voc (&$fd, &$ThisFileInfo) | |
| VOCcompressionTypeLookup ($index) | |
| VOCwFormatLookup ($index) | |
| VOCwFormatActualBitsPerSampleLookup ($index) | |
Detailed Description
getID3() by James Heinrich <info@getid3.org> //
Definition at line 17 of file module.audio.voc.php.
Member Function Documentation
| getid3_voc::getid3_voc | ( | &$ | fd, | |
| &$ | ThisFileInfo | |||
| ) |
Definition at line 20 of file module.audio.voc.php.
References getid3_lib::CastAsInt(), getid3_lib::LittleEndian2Int(), getid3_lib::trunc(), VOCcompressionTypeLookup(), VOCwFormatActualBitsPerSampleLookup(), and VOCwFormatLookup().
{
$OriginalAVdataOffset = $ThisFileInfo['avdataoffset'];
fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
$VOCheader = fread($fd, 26);
if (substr($VOCheader, 0, 19) != 'Creative Voice File') {
$ThisFileInfo['error'][] = 'Expecting "Creative Voice File" at offset '.$ThisFileInfo['avdataoffset'].', found "'.substr($VOCheader, 0, 19).'"';
return false;
}
// shortcuts
$thisfile_audio = &$ThisFileInfo['audio'];
$ThisFileInfo['voc'] = array();
$thisfile_voc = &$ThisFileInfo['voc'];
$ThisFileInfo['fileformat'] = 'voc';
$thisfile_audio['dataformat'] = 'voc';
$thisfile_audio['bitrate_mode'] = 'cbr';
$thisfile_audio['lossless'] = true;
$thisfile_audio['channels'] = 1; // might be overriden below
$thisfile_audio['bits_per_sample'] = 8; // might be overriden below
// byte # Description
// ------ ------------------------------------------
// 00-12 'Creative Voice File'
// 13 1A (eof to abort printing of file)
// 14-15 Offset of first datablock in .voc file (std 1A 00 in Intel Notation)
// 16-17 Version number (minor,major) (VOC-HDR puts 0A 01)
// 18-19 2's Comp of Ver. # + 1234h (VOC-HDR puts 29 11)
$thisfile_voc['header']['datablock_offset'] = getid3_lib::LittleEndian2Int(substr($VOCheader, 20, 2));
$thisfile_voc['header']['minor_version'] = getid3_lib::LittleEndian2Int(substr($VOCheader, 22, 1));
$thisfile_voc['header']['major_version'] = getid3_lib::LittleEndian2Int(substr($VOCheader, 23, 1));
do {
$BlockOffset = ftell($fd);
$BlockData = fread($fd, 4);
$BlockType = ord($BlockData{0});
$BlockSize = getid3_lib::LittleEndian2Int(substr($BlockData, 1, 3));
$ThisBlock = array();
@$thisfile_voc['blocktypes'][$BlockType]++;
switch ($BlockType) {
case 0: // Terminator
// do nothing, we'll break out of the loop down below
break;
case 1: // Sound data
$BlockData .= fread($fd, 2);
if ($ThisFileInfo['avdataoffset'] <= $OriginalAVdataOffset) {
$ThisFileInfo['avdataoffset'] = ftell($fd);
}
fseek($fd, $BlockSize - 2, SEEK_CUR);
$ThisBlock['sample_rate_id'] = getid3_lib::LittleEndian2Int(substr($BlockData, 4, 1));
$ThisBlock['compression_type'] = getid3_lib::LittleEndian2Int(substr($BlockData, 5, 1));
$ThisBlock['compression_name'] = $this->VOCcompressionTypeLookup($ThisBlock['compression_type']);
if ($ThisBlock['compression_type'] <= 3) {
$thisfile_voc['compressed_bits_per_sample'] = getid3_lib::CastAsInt(str_replace('-bit', '', $ThisBlock['compression_name']));
}
// Less accurate sample_rate calculation than the Extended block (#8) data (but better than nothing if Extended Block is not available)
if (empty($thisfile_audio['sample_rate'])) {
// SR byte = 256 - (1000000 / sample_rate)
$thisfile_audio['sample_rate'] = getid3_lib::trunc((1000000 / (256 - $ThisBlock['sample_rate_id'])) / $thisfile_audio['channels']);
}
break;
case 2: // Sound continue
case 3: // Silence
case 4: // Marker
case 6: // Repeat
case 7: // End repeat
// nothing useful, just skip
fseek($fd, $BlockSize, SEEK_CUR);
break;
case 8: // Extended
$BlockData .= fread($fd, 4);
//00-01 Time Constant:
// Mono: 65536 - (256000000 / sample_rate)
// Stereo: 65536 - (256000000 / (sample_rate * 2))
$ThisBlock['time_constant'] = getid3_lib::LittleEndian2Int(substr($BlockData, 4, 2));
$ThisBlock['pack_method'] = getid3_lib::LittleEndian2Int(substr($BlockData, 6, 1));
$ThisBlock['stereo'] = (bool) getid3_lib::LittleEndian2Int(substr($BlockData, 7, 1));
$thisfile_audio['channels'] = ($ThisBlock['stereo'] ? 2 : 1);
$thisfile_audio['sample_rate'] = getid3_lib::trunc((256000000 / (65536 - $ThisBlock['time_constant'])) / $thisfile_audio['channels']);
break;
case 9: // data block that supersedes blocks 1 and 8. Used for stereo, 16 bit
$BlockData .= fread($fd, 12);
if ($ThisFileInfo['avdataoffset'] <= $OriginalAVdataOffset) {
$ThisFileInfo['avdataoffset'] = ftell($fd);
}
fseek($fd, $BlockSize - 12, SEEK_CUR);
$ThisBlock['sample_rate'] = getid3_lib::LittleEndian2Int(substr($BlockData, 4, 4));
$ThisBlock['bits_per_sample'] = getid3_lib::LittleEndian2Int(substr($BlockData, 8, 1));
$ThisBlock['channels'] = getid3_lib::LittleEndian2Int(substr($BlockData, 9, 1));
$ThisBlock['wFormat'] = getid3_lib::LittleEndian2Int(substr($BlockData, 10, 2));
$ThisBlock['compression_name'] = $this->VOCwFormatLookup($ThisBlock['wFormat']);
if ($this->VOCwFormatActualBitsPerSampleLookup($ThisBlock['wFormat'])) {
$thisfile_voc['compressed_bits_per_sample'] = $this->VOCwFormatActualBitsPerSampleLookup($ThisBlock['wFormat']);
}
$thisfile_audio['sample_rate'] = $ThisBlock['sample_rate'];
$thisfile_audio['bits_per_sample'] = $ThisBlock['bits_per_sample'];
$thisfile_audio['channels'] = $ThisBlock['channels'];
break;
default:
$ThisFileInfo['warning'][] = 'Unhandled block type "'.$BlockType.'" at offset '.$BlockOffset;
fseek($fd, $BlockSize, SEEK_CUR);
break;
}
if (!empty($ThisBlock)) {
$ThisBlock['block_offset'] = $BlockOffset;
$ThisBlock['block_size'] = $BlockSize;
$ThisBlock['block_type_id'] = $BlockType;
$thisfile_voc['blocks'][] = $ThisBlock;
}
} while (!feof($fd) && ($BlockType != 0));
// Terminator block doesn't have size field, so seek back 3 spaces
fseek($fd, -3, SEEK_CUR);
ksort($thisfile_voc['blocktypes']);
if (!empty($thisfile_voc['compressed_bits_per_sample'])) {
$ThisFileInfo['playtime_seconds'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / ($thisfile_voc['compressed_bits_per_sample'] * $thisfile_audio['channels'] * $thisfile_audio['sample_rate']);
$thisfile_audio['bitrate'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / $ThisFileInfo['playtime_seconds'];
}
return true;
}
Here is the call graph for this function:
| getid3_voc::VOCcompressionTypeLookup | ( | $ | index | ) |
Definition at line 164 of file module.audio.voc.php.
Referenced by getid3_voc().
{
static $VOCcompressionTypeLookup = array(
0 => '8-bit',
1 => '4-bit',
2 => '2.6-bit',
3 => '2-bit'
);
return (isset($VOCcompressionTypeLookup[$index]) ? $VOCcompressionTypeLookup[$index] : 'Multi DAC ('.($index - 3).') channels');
}
Here is the caller graph for this function:
| getid3_voc::VOCwFormatActualBitsPerSampleLookup | ( | $ | index | ) |
Definition at line 188 of file module.audio.voc.php.
Referenced by getid3_voc().
{
static $VOCwFormatLookup = array(
0x0000 => 8,
0x0001 => 4,
0x0002 => 3,
0x0003 => 2,
0x0004 => 16,
0x0006 => 8,
0x0007 => 8,
0x2000 => 4
);
return (isset($VOCwFormatLookup[$index]) ? $VOCwFormatLookup[$index] : false);
}
Here is the caller graph for this function:
| getid3_voc::VOCwFormatLookup | ( | $ | index | ) |
Definition at line 174 of file module.audio.voc.php.
Referenced by getid3_voc().
{
static $VOCwFormatLookup = array(
0x0000 => '8-bit unsigned PCM',
0x0001 => 'Creative 8-bit to 4-bit ADPCM',
0x0002 => 'Creative 8-bit to 3-bit ADPCM',
0x0003 => 'Creative 8-bit to 2-bit ADPCM',
0x0004 => '16-bit signed PCM',
0x0006 => 'CCITT a-Law',
0x0007 => 'CCITT u-Law',
0x2000 => 'Creative 16-bit to 4-bit ADPCM'
);
return (isset($VOCwFormatLookup[$index]) ? $VOCwFormatLookup[$index] : false);
}
Here is the caller graph for this function:
The documentation for this class was generated from the following file:
- Services/MediaObjects/getid3/getid3/module.audio.voc.php
