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<?php
// +----------------------------------------------------------------------+
// | PHP version 5 |
// +----------------------------------------------------------------------+
// | Copyright (c) 2002-2006 James Heinrich, Allan Hansen |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2 of the GPL license, |
// | that is bundled with this package in the file license.txt and is |
// | available through the world-wide-web at the following url: |
// | http://www.gnu.org/copyleft/gpl.html |
// +----------------------------------------------------------------------+
// | getID3() - http://getid3.sourceforge.net or http://www.getid3.org |
// +----------------------------------------------------------------------+
// | Authors: James Heinrich <info�getid3*org> |
// | Allan Hansen <ah�artemis*dk> |
// +----------------------------------------------------------------------+
// | module.audio.voc.php |
// | Module for analyzing Creative VOC Audio files. |
// | dependencies: NONE |
// +----------------------------------------------------------------------+
//
// $Id: module.audio.voc.php,v 1.3 2006/11/02 10:48:02 ah Exp $
class getid3_voc extends getid3_handler
{
public function Analyze() {
$getid3 = $this->getid3;
$original_av_data_offset = $getid3->info['avdataoffset'];
fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET);
$voc_header= fread($getid3->fp, 26);
// Magic bytes: 'Creative Voice File'
$info_audio = &$getid3->info['audio'];
$getid3->info['voc'] = array ();
$info_voc = &$getid3->info['voc'];
$getid3->info['fileformat'] = 'voc';
$info_audio['dataformat'] = 'voc';
$info_audio['bitrate_mode'] = 'cbr';
$info_audio['lossless'] = true;
$info_audio['channels'] = 1; // might be overriden below
$info_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)
getid3_lib::ReadSequence('LittleEndian2Int', $info_voc['header'], $voc_header, 20,
array (
'datablock_offset' => 2,
'minor_version' => 1,
'major_version' => 1
)
);
do {
$block_offset = ftell($getid3->fp);
$block_data = fread($getid3->fp, 4);
$block_type = ord($block_data{0});
$block_size = getid3_lib::LittleEndian2Int(substr($block_data, 1, 3));
$this_block = array ();
@$info_voc['blocktypes'][$block_type]++;
switch ($block_type) {
case 0: // Terminator
// do nothing, we'll break out of the loop down below
break;
case 1: // Sound data
$block_data .= fread($getid3->fp, 2);
if ($getid3->info['avdataoffset'] <= $original_av_data_offset) {
$getid3->info['avdataoffset'] = ftell($getid3->fp);
}
fseek($getid3->fp, $block_size - 2, SEEK_CUR);
getid3_lib::ReadSequence('LittleEndian2Int', $this_block, $block_data, 4,
array (
'sample_rate_id' => 1,
'compression_type' => 1
)
);
$this_block['compression_name'] = getid3_voc::VOCcompressionTypeLookup($this_block['compression_type']);
if ($this_block['compression_type'] <= 3) {
$info_voc['compressed_bits_per_sample'] = (int)(str_replace('-bit', '', $this_block['compression_name']));
}
// Less accurate sample_rate calculation than the Extended block (#8) data (but better than nothing if Extended Block is not available)
if (empty($info_audio['sample_rate'])) {
// SR byte = 256 - (1000000 / sample_rate)
$info_audio['sample_rate'] = (int)floor((1000000 / (256 - $this_block['sample_rate_id'])) / $info_audio['channels']);
}
break;
case 2: // Sound continue
case 3: // Silence
case 4: // Marker
case 6: // Repeat
case 7: // End repeat
// nothing useful, just skip
fseek($getid3->fp, $block_size, SEEK_CUR);
break;
case 8: // Extended
$block_data .= fread($getid3->fp, 4);
//00-01 Time Constant:
// Mono: 65536 - (256000000 / sample_rate)
// Stereo: 65536 - (256000000 / (sample_rate * 2))
getid3_lib::ReadSequence('LittleEndian2Int', $this_block, $block_data, 4,
array (
'time_constant' => 2,
'pack_method' => 1,
'stereo' => 1
)
);
$this_block['stereo'] = (bool)$this_block['stereo'];
$info_audio['channels'] = ($this_block['stereo'] ? 2 : 1);
$info_audio['sample_rate'] = (int)floor((256000000 / (65536 - $this_block['time_constant'])) / $info_audio['channels']);
break;
case 9: // data block that supersedes blocks 1 and 8. Used for stereo, 16 bit
$block_data .= fread($getid3->fp, 12);
if ($getid3->info['avdataoffset'] <= $original_av_data_offset) {
$getid3->info['avdataoffset'] = ftell($getid3->fp);
}
fseek($getid3->fp, $block_size - 12, SEEK_CUR);
getid3_lib::ReadSequence('LittleEndian2Int', $this_block, $block_data, 4,
array (
'sample_rate' => 4,
'bits_per_sample' => 1,
'channels' => 1,
'wFormat' => 2
)
);
$this_block['compression_name'] = getid3_voc::VOCwFormatLookup($this_block['wFormat']);
if (getid3_voc::VOCwFormatActualBitsPerSampleLookup($this_block['wFormat'])) {
$info_voc['compressed_bits_per_sample'] = getid3_voc::VOCwFormatActualBitsPerSampleLookup($this_block['wFormat']);
}
$info_audio['sample_rate'] = $this_block['sample_rate'];
$info_audio['bits_per_sample'] = $this_block['bits_per_sample'];
$info_audio['channels'] = $this_block['channels'];
break;
default:
$getid3->warning('Unhandled block type "'.$block_type.'" at offset '.$block_offset);
fseek($getid3->fp, $block_size, SEEK_CUR);
break;
}
if (!empty($this_block)) {
$this_block['block_offset'] = $block_offset;
$this_block['block_size'] = $block_size;
$this_block['block_type_id'] = $block_type;
$info_voc['blocks'][] = $this_block;
}
} while (!feof($getid3->fp) && ($block_type != 0));
// Terminator block doesn't have size field, so seek back 3 spaces
fseek($getid3->fp, -3, SEEK_CUR);
ksort($info_voc['blocktypes']);
if (!empty($info_voc['compressed_bits_per_sample'])) {
$getid3->info['playtime_seconds'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / ($info_voc['compressed_bits_per_sample'] * $info_audio['channels'] * $info_audio['sample_rate']);
$info_audio['bitrate'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / $getid3->info['playtime_seconds'];
}
return true;
}
public static function VOCcompressionTypeLookup($index) {
static $lookup = array (
0 => '8-bit',
1 => '4-bit',
2 => '2.6-bit',
3 => '2-bit'
);
return (isset($lookup[$index]) ? $lookup[$index] : 'Multi DAC ('.($index - 3).') channels');
}
public static function VOCwFormatLookup($index) {
static $lookup = array (
0x0000 => '8-bit unsigned PCM',
0x0001 => 'Creative 8-bit to 4-bit ADPCM',
0x0002 => 'Creative 8-bit to 3-bit ADPCM',
0x0003 => 'Creative 8-bit to 2-bit ADPCM',
0x0004 => '16-bit signed PCM',
0x0006 => 'CCITT a-Law',
0x0007 => 'CCITT u-Law',
0x2000 => 'Creative 16-bit to 4-bit ADPCM'
);
return (isset($lookup[$index]) ? $lookup[$index] : false);
}
public static function VOCwFormatActualBitsPerSampleLookup($index) {
static $lookup = array (
0x0000 => 8,
0x0001 => 4,
0x0002 => 3,
0x0003 => 2,
0x0004 => 16,
0x0006 => 8,
0x0007 => 8,
0x2000 => 4
);
return (isset($lookup[$index]) ? $lookup[$index] : false);
}
}
?>
|
