/lib/getid3/module.audio.voc.php
PHP | 240 lines | 153 code | 50 blank | 37 comment | 11 complexity | 209d66b1defcb2396b83243162390429 MD5 | raw file
Possible License(s): LGPL-2.1
- <?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);
- }
- }
- ?>