diff options
author | Karl 'vollmerk' Vollmer <vollmer@ampache.org> | 2007-04-23 07:31:05 +0000 |
---|---|---|
committer | Karl 'vollmerk' Vollmer <vollmer@ampache.org> | 2007-04-23 07:31:05 +0000 |
commit | a31560aec4f004e58930277758f5412d86c62adc (patch) | |
tree | 845ff6947d26b22a0f4527901dbefc97bca89d78 /modules/getid3/module.audio.ac3.php | |
parent | 8b27d66add7ca9ba57d7e9488612cb54be4b11c1 (diff) | |
download | ampache-a31560aec4f004e58930277758f5412d86c62adc.tar.gz ampache-a31560aec4f004e58930277758f5412d86c62adc.tar.bz2 ampache-a31560aec4f004e58930277758f5412d86c62adc.zip |
it technically logs in and streams.. but thats it, complete rewrite almost everything broken
Diffstat (limited to 'modules/getid3/module.audio.ac3.php')
-rw-r--r-- | modules/getid3/module.audio.ac3.php | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/modules/getid3/module.audio.ac3.php b/modules/getid3/module.audio.ac3.php new file mode 100644 index 00000000..7bb8f9f8 --- /dev/null +++ b/modules/getid3/module.audio.ac3.php @@ -0,0 +1,500 @@ +<?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 <infoุgetid3*org> | +// | Allan Hansen <ahุartemis*dk> | +// +----------------------------------------------------------------------+ +// | module.audio.ac3.php | +// | Module for analyzing AC-3 (aka Dolby Digital) audio files | +// | dependencies: NONE | +// +----------------------------------------------------------------------+ +// +// $Id: module.audio.ac3.php,v 1.3 2006/11/02 10:48:01 ah Exp $ + + + +class getid3_ac3 extends getid3_handler +{ + + public function Analyze() { + + $getid3 = $this->getid3; + + // http://www.atsc.org/standards/a_52a.pdf + + $getid3->info['fileformat'] = 'ac3'; + $getid3->info['audio']['dataformat'] = 'ac3'; + $getid3->info['audio']['bitrate_mode'] = 'cbr'; + $getid3->info['audio']['lossless'] = false; + + $getid3->info['ac3']['raw']['bsi'] = array (); + $info_ac3 = &$getid3->info['ac3']; + $info_ac3_raw = &$info_ac3['raw']; + $info_ac3_raw_bsi = &$info_ac3_raw['bsi']; + + + // An AC-3 serial coded audio bit stream is made up of a sequence of synchronization frames + // Each synchronization frame contains 6 coded audio blocks (AB), each of which represent 256 + // new audio samples per channel. A synchronization information (SI) header at the beginning + // of each frame contains information needed to acquire and maintain synchronization. A + // bit stream information (BSI) header follows SI, and contains parameters describing the coded + // audio service. The coded audio blocks may be followed by an auxiliary data (Aux) field. At the + // end of each frame is an error check field that includes a CRC word for error detection. An + // additional CRC word is located in the SI header, the use of which, by a decoder, is optional. + // + // syncinfo() | bsi() | AB0 | AB1 | AB2 | AB3 | AB4 | AB5 | Aux | CRC + + $this->fseek($getid3->info['avdataoffset'], SEEK_SET); + $ac3_header['syncinfo'] = $this->fread(5); + $info_ac3_raw['synchinfo']['synchword'] = substr($ac3_header['syncinfo'], 0, 2); + + if ($info_ac3_raw['synchinfo']['synchword'] != "\x0B\x77") { + throw new getid3_exception('Expecting "\x0B\x77" at offset '.$getid3->info['avdataoffset'].', found \x'.strtoupper(dechex($ac3_header['syncinfo']{0})).'\x'.strtoupper(dechex($ac3_header['syncinfo']{1})).' instead'); + } + + + // syncinfo() { + // syncword 16 + // crc1 16 + // fscod 2 + // frmsizecod 6 + // } /* end of syncinfo */ + + $info_ac3_raw['synchinfo']['crc1'] = getid3_lib::LittleEndian2Int(substr($ac3_header['syncinfo'], 2, 2)); + $ac3_synchinfo_fscod_frmsizecod = getid3_lib::LittleEndian2Int(substr($ac3_header['syncinfo'], 4, 1)); + $info_ac3_raw['synchinfo']['fscod'] = ($ac3_synchinfo_fscod_frmsizecod & 0xC0) >> 6; + $info_ac3_raw['synchinfo']['frmsizecod'] = ($ac3_synchinfo_fscod_frmsizecod & 0x3F); + + $info_ac3['sample_rate'] = getid3_ac3::AC3sampleRateCodeLookup($info_ac3_raw['synchinfo']['fscod']); + if ($info_ac3_raw['synchinfo']['fscod'] <= 3) { + $getid3->info['audio']['sample_rate'] = $info_ac3['sample_rate']; + } + + $info_ac3['frame_length'] = getid3_ac3::AC3frameSizeLookup($info_ac3_raw['synchinfo']['frmsizecod'], $info_ac3_raw['synchinfo']['fscod']); + $info_ac3['bitrate'] = getid3_ac3::AC3bitrateLookup($info_ac3_raw['synchinfo']['frmsizecod']); + $getid3->info['audio']['bitrate'] = $info_ac3['bitrate']; + + $ac3_header['bsi'] = getid3_lib::BigEndian2Bin($this->fread(15)); + + $info_ac3_raw_bsi['bsid'] = bindec(substr($ac3_header['bsi'], 0, 5)); + if ($info_ac3_raw_bsi['bsid'] > 8) { + // Decoders which can decode version 8 will thus be able to decode version numbers less than 8. + // If this standard is extended by the addition of additional elements or features, a value of bsid greater than 8 will be used. + // Decoders built to this version of the standard will not be able to decode versions with bsid greater than 8. + throw new getid3_exception('Bit stream identification is version '.$info_ac3_raw_bsi['bsid'].', but getID3() only understands up to version 8'); + } + + $info_ac3_raw_bsi['bsmod'] = bindec(substr($ac3_header['bsi'], 5, 3)); + $info_ac3_raw_bsi['acmod'] = bindec(substr($ac3_header['bsi'], 8, 3)); + + $info_ac3['service_type'] = getid3_ac3::AC3serviceTypeLookup($info_ac3_raw_bsi['bsmod'], $info_ac3_raw_bsi['acmod']); + $ac3_coding_mode = getid3_ac3::AC3audioCodingModeLookup($info_ac3_raw_bsi['acmod']); + foreach($ac3_coding_mode as $key => $value) { + $info_ac3[$key] = $value; + } + switch ($info_ac3_raw_bsi['acmod']) { + case 0: + case 1: + $getid3->info['audio']['channelmode'] = 'mono'; + break; + case 3: + case 4: + $getid3->info['audio']['channelmode'] = 'stereo'; + break; + default: + $getid3->info['audio']['channelmode'] = 'surround'; + break; + } + $getid3->info['audio']['channels'] = $info_ac3['num_channels']; + + $offset = 11; + + if ($info_ac3_raw_bsi['acmod'] & 0x01) { + // If the lsb of acmod is a 1, center channel is in use and cmixlev follows in the bit stream. + $info_ac3_raw_bsi['cmixlev'] = bindec(substr($ac3_header['bsi'], $offset, 2)); + $info_ac3['center_mix_level'] = getid3_ac3::AC3centerMixLevelLookup($info_ac3_raw_bsi['cmixlev']); + $offset += 2; + } + + if ($info_ac3_raw_bsi['acmod'] & 0x04) { + // If the msb of acmod is a 1, surround channels are in use and surmixlev follows in the bit stream. + $info_ac3_raw_bsi['surmixlev'] = bindec(substr($ac3_header['bsi'], $offset, 2)); + $info_ac3['surround_mix_level'] = getid3_ac3::AC3surroundMixLevelLookup($info_ac3_raw_bsi['surmixlev']); + $offset += 2; + } + + if ($info_ac3_raw_bsi['acmod'] == 0x02) { + // When operating in the two channel mode, this 2-bit code indicates whether or not the program has been encoded in Dolby Surround. + $info_ac3_raw_bsi['dsurmod'] = bindec(substr($ac3_header['bsi'], $offset, 2)); + $info_ac3['dolby_surround_mode'] = getid3_ac3::AC3dolbySurroundModeLookup($info_ac3_raw_bsi['dsurmod']); + $offset += 2; + } + + $info_ac3_raw_bsi['lfeon'] = $ac3_header['bsi']{$offset++} == '1'; + $info_ac3['lfe_enabled'] = $info_ac3_raw_bsi['lfeon']; + if ($info_ac3_raw_bsi['lfeon']) { + $getid3->info['audio']['channels'] .= '.1'; + } + + $info_ac3['channels_enabled'] = getid3_ac3::AC3channelsEnabledLookup($info_ac3_raw_bsi['acmod'], $info_ac3_raw_bsi['lfeon']); + + // This indicates how far the average dialogue level is below digital 100 percent. Valid values are 131. + // The value of 0 is reserved. The values of 1 to 31 are interpreted as -1 dB to -31 dB with respect to digital 100 percent. + $info_ac3_raw_bsi['dialnorm'] = bindec(substr($ac3_header['bsi'], $offset, 5)); + $offset += 5; + $info_ac3['dialogue_normalization'] = '-'.$info_ac3_raw_bsi['dialnorm'].'dB'; + + $info_ac3_raw_bsi['compre_flag'] = $ac3_header['bsi']{$offset++} == '1'; + if ($info_ac3_raw_bsi['compre_flag']) { + $info_ac3_raw_bsi['compr'] = bindec(substr($ac3_header['bsi'], $offset, 8)); + $offset += 8; + + $info_ac3['heavy_compression'] = getid3_ac3::AC3heavyCompression($info_ac3_raw_bsi['compr']); + } + + $info_ac3_raw_bsi['langcode_flag'] = $ac3_header['bsi']{$offset++} == '1'; + if ($info_ac3_raw_bsi['langcode_flag']) { + $info_ac3_raw_bsi['langcod'] = bindec(substr($ac3_header['bsi'], $offset, 8)); + $offset += 8; + } + + $info_ac3_raw_bsi['audprodie'] = $ac3_header['bsi']{$offset++} == '1'; + if ($info_ac3_raw_bsi['audprodie']) { + $info_ac3_raw_bsi['mixlevel'] = bindec(substr($ac3_header['bsi'], $offset, 5)); + $offset += 5; + + $info_ac3_raw_bsi['roomtyp'] = bindec(substr($ac3_header['bsi'], $offset, 2)); + $offset += 2; + + $info_ac3['mixing_level'] = (80 + $info_ac3_raw_bsi['mixlevel']).'dB'; + $info_ac3['room_type'] = getid3_ac3::AC3roomTypeLookup($info_ac3_raw_bsi['roomtyp']); + } + + if ($info_ac3_raw_bsi['acmod'] == 0x00) { + // If acmod is 0, then two completely independent program channels (dual mono) + // are encoded into the bit stream, and are referenced as Ch1, Ch2. In this case, + // a number of additional items are present in BSI or audblk to fully describe Ch2. + + + // This indicates how far the average dialogue level is below digital 100 percent. Valid values are 131. + // The value of 0 is reserved. The values of 1 to 31 are interpreted as -1 dB to -31 dB with respect to digital 100 percent. + $info_ac3_raw_bsi['dialnorm2'] = bindec(substr($ac3_header['bsi'], $offset, 5)); + $offset += 5; + + $info_ac3['dialogue_normalization2'] = '-'.$info_ac3_raw_bsi['dialnorm2'].'dB'; + + $info_ac3_raw_bsi['compre_flag2'] = $ac3_header['bsi']{$offset++} == '1'; + if ($info_ac3_raw_bsi['compre_flag2']) { + $info_ac3_raw_bsi['compr2'] = bindec(substr($ac3_header['bsi'], $offset, 8)); + $offset += 8; + + $info_ac3['heavy_compression2'] = getid3_ac3::AC3heavyCompression($info_ac3_raw_bsi['compr2']); + } + + $info_ac3_raw_bsi['langcode_flag2'] = $ac3_header['bsi']{$offset++} == '1'; + if ($info_ac3_raw_bsi['langcode_flag2']) { + $info_ac3_raw_bsi['langcod2'] = bindec(substr($ac3_header['bsi'], $offset, 8)); + $offset += 8; + } + + $info_ac3_raw_bsi['audprodie2'] = $ac3_header['bsi']{$offset++} == '1'; + if ($info_ac3_raw_bsi['audprodie2']) { + $info_ac3_raw_bsi['mixlevel2'] = bindec(substr($ac3_header['bsi'], $offset, 5)); + $offset += 5; + + $info_ac3_raw_bsi['roomtyp2'] = bindec(substr($ac3_header['bsi'], $offset, 2)); + $offset += 2; + + $info_ac3['mixing_level2'] = (80 + $info_ac3_raw_bsi['mixlevel2']).'dB'; + $info_ac3['room_type2'] = getid3_ac3::AC3roomTypeLookup($info_ac3_raw_bsi['roomtyp2']); + } + + } + + $info_ac3_raw_bsi['copyright'] = $ac3_header['bsi']{$offset++} == '1'; + + $info_ac3_raw_bsi['original'] = $ac3_header['bsi']{$offset++} == '1'; + + $info_ac3_raw_bsi['timecode1_flag'] = $ac3_header['bsi']{$offset++} == '1'; + if ($info_ac3_raw_bsi['timecode1_flag']) { + $info_ac3_raw_bsi['timecode1'] = bindec(substr($ac3_header['bsi'], $offset, 14)); + $offset += 14; + } + + $info_ac3_raw_bsi['timecode2_flag'] = $ac3_header['bsi']{$offset++} == '1'; + if ($info_ac3_raw_bsi['timecode2_flag']) { + $info_ac3_raw_bsi['timecode2'] = bindec(substr($ac3_header['bsi'], $offset, 14)); + $offset += 14; + } + + $info_ac3_raw_bsi['addbsi_flag'] = $ac3_header['bsi']{$offset++} == '1'; + if ($info_ac3_raw_bsi['addbsi_flag']) { + $info_ac3_raw_bsi['addbsi_length'] = bindec(substr($ac3_header['bsi'], $offset, 6)); + $offset += 6; + + $ac3_header['bsi'] .= getid3_lib::BigEndian2Bin($this->fread($info_ac3_raw_bsi['addbsi_length'])); + + $info_ac3_raw_bsi['addbsi_data'] = substr($ac3_header['bsi'], 119, $info_ac3_raw_bsi['addbsi_length'] * 8); + } + + return true; + } + + + + public static function AC3sampleRateCodeLookup($fscod) { + + static $lookup = array ( + 0 => 48000, + 1 => 44100, + 2 => 32000, + 3 => 'reserved' // If the reserved code is indicated, the decoder should not attempt to decode audio and should mute. + ); + return (isset($lookup[$fscod]) ? $lookup[$fscod] : false); + } + + + + public static function AC3serviceTypeLookup($bsmod, $acmod) { + + static $lookup = array ( + 0 => 'main audio service: complete main (CM)', + 1 => 'main audio service: music and effects (ME)', + 2 => 'associated service: visually impaired (VI)', + 3 => 'associated service: hearing impaired (HI)', + 4 => 'associated service: dialogue (D)', + 5 => 'associated service: commentary (C)', + 6 => 'associated service: emergency (E)', + 7 => 'main audio service: karaoke' + ); + + if ($bsmod == 7 && $acmod == 1) { + return 'associated service: voice over (VO)'; + } + + return (isset($lookup[$bsmod]) ? $lookup[$bsmod] : false); + } + + + + public static function AC3audioCodingModeLookup($acmod) { + + // array (channel configuration, # channels (not incl LFE), channel order) + static $lookup = array ( + 0 => array ('channel_config'=>'1+1', 'num_channels'=>2, 'channel_order'=>'Ch1,Ch2'), + 1 => array ('channel_config'=>'1/0', 'num_channels'=>1, 'channel_order'=>'C'), + 2 => array ('channel_config'=>'2/0', 'num_channels'=>2, 'channel_order'=>'L,R'), + 3 => array ('channel_config'=>'3/0', 'num_channels'=>3, 'channel_order'=>'L,C,R'), + 4 => array ('channel_config'=>'2/1', 'num_channels'=>3, 'channel_order'=>'L,R,S'), + 5 => array ('channel_config'=>'3/1', 'num_channels'=>4, 'channel_order'=>'L,C,R,S'), + 6 => array ('channel_config'=>'2/2', 'num_channels'=>4, 'channel_order'=>'L,R,SL,SR'), + 7 => array ('channel_config'=>'3/2', 'num_channels'=>5, 'channel_order'=>'L,C,R,SL,SR') + ); + return (isset($lookup[$acmod]) ? $lookup[$acmod] : false); + } + + + + public static function AC3centerMixLevelLookup($cmixlev) { + + static $lookup; + if (!@$lookup) { + $lookup = array ( + 0 => pow(2, -3.0 / 6), // 0.707 (3.0 dB) + 1 => pow(2, -4.5 / 6), // 0.595 (4.5 dB) + 2 => pow(2, -6.0 / 6), // 0.500 (6.0 dB) + 3 => 'reserved' + ); + } + return (isset($lookup[$cmixlev]) ? $lookup[$cmixlev] : false); + } + + + + public static function AC3surroundMixLevelLookup($surmixlev) { + + static $lookup; + if (!@$lookup) { + $lookup = array ( + 0 => pow(2, -3.0 / 6), + 1 => pow(2, -6.0 / 6), + 2 => 0, + 3 => 'reserved' + ); + } + return (isset($lookup[$surmixlev]) ? $lookup[$surmixlev] : false); + } + + + + public static function AC3dolbySurroundModeLookup($dsurmod) { + + static $lookup = array ( + 0 => 'not indicated', + 1 => 'Not Dolby Surround encoded', + 2 => 'Dolby Surround encoded', + 3 => 'reserved' + ); + return (isset($lookup[$dsurmod]) ? $lookup[$dsurmod] : false); + } + + + + public static function AC3channelsEnabledLookup($acmod, $lfeon) { + + return array ( + 'ch1' => $acmod == 0, + 'ch2' => $acmod == 0, + 'left' => $acmod > 1, + 'right' => $acmod > 1, + 'center' => (bool)($acmod & 0x01), + 'surround_mono' => $acmod == 4 || $acmod == 5, + 'surround_left' => $acmod == 6 || $acmod == 7, + 'surround_right' => $acmod == 6 || $acmod == 7, + 'lfe' => $lfeon + ); + } + + + + public static function AC3heavyCompression($compre) { + + // The first four bits indicate gain changes in 6.02dB increments which can be + // implemented with an arithmetic shift operation. The following four bits + // indicate linear gain changes, and require a 5-bit multiply. + // We will represent the two 4-bit fields of compr as follows: + // X0 X1 X2 X3 . Y4 Y5 Y6 Y7 + // The meaning of the X values is most simply described by considering X to represent a 4-bit + // signed integer with values from 8 to +7. The gain indicated by X is then (X + 1) * 6.02 dB. The + // following table shows this in detail. + + // Meaning of 4 msb of compr + // 7 +48.16 dB + // 6 +42.14 dB + // 5 +36.12 dB + // 4 +30.10 dB + // 3 +24.08 dB + // 2 +18.06 dB + // 1 +12.04 dB + // 0 +6.02 dB + // -1 0 dB + // -2 6.02 dB + // -3 12.04 dB + // -4 18.06 dB + // -5 24.08 dB + // -6 30.10 dB + // -7 36.12 dB + // -8 42.14 dB + + $fourbit = str_pad(decbin(($compre & 0xF0) >> 4), 4, '0', STR_PAD_LEFT); + if ($fourbit{0} == '1') { + $log_gain = -8 + bindec(substr($fourbit, 1)); + } else { + $log_gain = bindec(substr($fourbit, 1)); + } + $log_gain = ($log_gain + 1) * (20 * log10(2)); + + // The value of Y is a linear representation of a gain change of up to 6 dB. Y is considered to + // be an unsigned fractional integer, with a leading value of 1, or: 0.1 Y4 Y5 Y6 Y7 (base 2). Y can + // represent values between 0.111112 (or 31/32) and 0.100002 (or 1/2). Thus, Y can represent gain + // changes from 0.28 dB to 6.02 dB. + + $lin_gain = (16 + ($compre & 0x0F)) / 32; + + // The combination of X and Y values allows compr to indicate gain changes from + // 48.16 0.28 = +47.89 dB, to + // 42.14 6.02 = 48.16 dB. + + return $log_gain - $lin_gain; + } + + + + public static function AC3roomTypeLookup($roomtyp) { + + static $lookup = array ( + 0 => 'not indicated', + 1 => 'large room, X curve monitor', + 2 => 'small room, flat monitor', + 3 => 'reserved' + ); + return (isset($lookup[$roomtyp]) ? $lookup[$roomtyp] : false); + } + + + + public static function AC3frameSizeLookup($frmsizecod, $fscod) { + + $padding = (bool)($frmsizecod % 2); + $frame_size_id = floor($frmsizecod / 2); + + static $lookup = array ( + 0 => array (128, 138, 192), + 1 => array (40, 160, 174, 240), + 2 => array (48, 192, 208, 288), + 3 => array (56, 224, 242, 336), + 4 => array (64, 256, 278, 384), + 5 => array (80, 320, 348, 480), + 6 => array (96, 384, 416, 576), + 7 => array (112, 448, 486, 672), + 8 => array (128, 512, 556, 768), + 9 => array (160, 640, 696, 960), + 10 => array (192, 768, 834, 1152), + 11 => array (224, 896, 974, 1344), + 12 => array (256, 1024, 1114, 1536), + 13 => array (320, 1280, 1392, 1920), + 14 => array (384, 1536, 1670, 2304), + 15 => array (448, 1792, 1950, 2688), + 16 => array (512, 2048, 2228, 3072), + 17 => array (576, 2304, 2506, 3456), + 18 => array (640, 2560, 2786, 3840) + ); + if (($fscod == 1) && $padding) { + // frame lengths are padded by 1 word (16 bits) at 44100 + $lookup[$frmsizecod] += 2; + } + return (isset($lookup[$frame_size_id][$fscod]) ? $lookup[$frame_size_id][$fscod] : false); + } + + + + public static function AC3bitrateLookup($frmsizecod) { + + static $lookup = array ( + 0 => 32000, + 1 => 40000, + 2 => 48000, + 3 => 56000, + 4 => 64000, + 5 => 80000, + 6 => 96000, + 7 => 112000, + 8 => 128000, + 9 => 160000, + 10 => 192000, + 11 => 224000, + 12 => 256000, + 13 => 320000, + 14 => 384000, + 15 => 448000, + 16 => 512000, + 17 => 576000, + 18 => 640000 + ); + $frame_size_id = floor($frmsizecod / 2); + return (isset($lookup[$frame_size_id]) ? $lookup[$frame_size_id] : false); + } + +} + +?>
\ No newline at end of file |