getid3_ac3::AC3sampleRateCodeLookup() - Code Metrics - Inspection of "updates" - mambax7/xoopseditors - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Branch — master (f2d2e3)

by Michael

created 2020-01-01 01:43 UTC

getid3_ac3::AC3sampleRateCodeLookup() A

↳ Parent: getid3_ac3

Complexity

Conditions	2
Paths	2

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	2
c	1
b	0
f	0
nc	2
dl	0
loc	9
rs	9.9666

<?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.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 1�31.
        // 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 1�31.
            // 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);
    }

}

?>


1			<?php
2			// +----------------------------------------------------------------------+
3			// \| PHP version 5 \|
4			// +----------------------------------------------------------------------+
5			// \| Copyright (c) 2002-2006 James Heinrich, Allan Hansen \|
6			// +----------------------------------------------------------------------+
7			// \| This source file is subject to version 2 of the GPL license, \|
8			// \| that is bundled with this package in the file license.txt and is \|
9			// \| available through the world-wide-web at the following url: \|
10			// \| http://www.gnu.org/copyleft/gpl.html \|
11			// +----------------------------------------------------------------------+
12			// \| getID3() - http://getid3.sourceforge.net or http://www.getid3.org \|
13			// +----------------------------------------------------------------------+
14			// \| Authors: James Heinrich <info�getid3*org> \|
15			// \| Allan Hansen <ah�artemis*dk> \|
16			// +----------------------------------------------------------------------+
17			// \| module.audio.ac3.php \|
18			// \| Module for analyzing AC-3 (aka Dolby Digital) audio files \|
19			// \| dependencies: NONE \|
20			// +----------------------------------------------------------------------+
21			//
22			// $Id: module.audio.ac3.php,v 1.3 2006/11/02 10:48:01 ah Exp $
23
24
25
26			class getid3_ac3 extends getid3_handler
27			{
28
29			public function Analyze() {
30
31			$getid3 = $this->getid3;
32
33			// http://www.atsc.org/standards/a_52a.pdf
34
35			$getid3->info['fileformat'] = 'ac3';
36			$getid3->info['audio']['dataformat'] = 'ac3';
37			$getid3->info['audio']['bitrate_mode'] = 'cbr';
38			$getid3->info['audio']['lossless'] = false;
39
40			$getid3->info['ac3']['raw']['bsi'] = array ();
41			$info_ac3 = &$getid3->info['ac3'];
42			$info_ac3_raw = &$info_ac3['raw'];
43			$info_ac3_raw_bsi = &$info_ac3_raw['bsi'];
44
45
46			// An AC-3 serial coded audio bit stream is made up of a sequence of synchronization frames
47			// Each synchronization frame contains 6 coded audio blocks (AB), each of which represent 256
48			// new audio samples per channel. A synchronization information (SI) header at the beginning
49			// of each frame contains information needed to acquire and maintain synchronization. A
50			// bit stream information (BSI) header follows SI, and contains parameters describing the coded
51			// audio service. The coded audio blocks may be followed by an auxiliary data (Aux) field. At the
52			// end of each frame is an error check field that includes a CRC word for error detection. An
53			// additional CRC word is located in the SI header, the use of which, by a decoder, is optional.
54			//
55			// syncinfo() \| bsi() \| AB0 \| AB1 \| AB2 \| AB3 \| AB4 \| AB5 \| Aux \| CRC
56
57			$this->fseek($getid3->info['avdataoffset'], SEEK_SET);
58			$ac3_header['syncinfo'] = $this->fread(5);
			0 ignored issues – show Comprehensibility Best Practice introduced 2020-01-01 02:01 UTC by Report Bug Copy Issue Report `$ac3_header` was never initialized. Although not strictly required by PHP, it is generally a good practice to add `$ac3_header = array();` before regardless. Loading history...
59			$info_ac3_raw['synchinfo']['synchword'] = substr($ac3_header['syncinfo'], 0, 2);
60
61			if ($info_ac3_raw['synchinfo']['synchword'] != "\x0B\x77") {
62			throw new getid3_exception('Expecting "\x0B\x77" at offset '.$getid3->info['avdataoffset'].', found \x'.strtoupper(dechex($ac3_header['syncinfo']{0})).'\x'.strtoupper(dechex($ac3_header['syncinfo']{1})).' instead');
63			}
64
65
66			// syncinfo() {
67			// syncword 16
68			// crc1 16
69			// fscod 2
70			// frmsizecod 6
71			// } /* end of syncinfo */
72
73			$info_ac3_raw['synchinfo']['crc1'] = getid3_lib::LittleEndian2Int(substr($ac3_header['syncinfo'], 2, 2));
74			$ac3_synchinfo_fscod_frmsizecod = getid3_lib::LittleEndian2Int(substr($ac3_header['syncinfo'], 4, 1));
75			$info_ac3_raw['synchinfo']['fscod'] = ($ac3_synchinfo_fscod_frmsizecod & 0xC0) >> 6;
76			$info_ac3_raw['synchinfo']['frmsizecod'] = ($ac3_synchinfo_fscod_frmsizecod & 0x3F);
77
78			$info_ac3['sample_rate'] = getid3_ac3::AC3sampleRateCodeLookup($info_ac3_raw['synchinfo']['fscod']);
79			if ($info_ac3_raw['synchinfo']['fscod'] <= 3) {
80			$getid3->info['audio']['sample_rate'] = $info_ac3['sample_rate'];
81			}
82
83			$info_ac3['frame_length'] = getid3_ac3::AC3frameSizeLookup($info_ac3_raw['synchinfo']['frmsizecod'], $info_ac3_raw['synchinfo']['fscod']);
84			$info_ac3['bitrate'] = getid3_ac3::AC3bitrateLookup($info_ac3_raw['synchinfo']['frmsizecod']);
85			$getid3->info['audio']['bitrate'] = $info_ac3['bitrate'];
86
87			$ac3_header['bsi'] = getid3_lib::BigEndian2Bin($this->fread(15));
88
89			$info_ac3_raw_bsi['bsid'] = bindec(substr($ac3_header['bsi'], 0, 5));
90			if ($info_ac3_raw_bsi['bsid'] > 8) {
91			// Decoders which can decode version 8 will thus be able to decode version numbers less than 8.
92			// If this standard is extended by the addition of additional elements or features, a value of bsid greater than 8 will be used.
93			// Decoders built to this version of the standard will not be able to decode versions with bsid greater than 8.
94			throw new getid3_exception('Bit stream identification is version '.$info_ac3_raw_bsi['bsid'].', but getID3() only understands up to version 8');
95			}
96
97			$info_ac3_raw_bsi['bsmod'] = bindec(substr($ac3_header['bsi'], 5, 3));
98			$info_ac3_raw_bsi['acmod'] = bindec(substr($ac3_header['bsi'], 8, 3));
99
100			$info_ac3['service_type'] = getid3_ac3::AC3serviceTypeLookup($info_ac3_raw_bsi['bsmod'], $info_ac3_raw_bsi['acmod']);
101			$ac3_coding_mode = getid3_ac3::AC3audioCodingModeLookup($info_ac3_raw_bsi['acmod']);
102			foreach($ac3_coding_mode as $key => $value) {
103			$info_ac3[$key] = $value;
104			}
105			switch ($info_ac3_raw_bsi['acmod']) {
106			case 0:
107			case 1:
108			$getid3->info['audio']['channelmode'] = 'mono';
109			break;
110			case 3:
111			case 4:
112			$getid3->info['audio']['channelmode'] = 'stereo';
113			break;
114			default:
115			$getid3->info['audio']['channelmode'] = 'surround';
116			break;
117			}
118			$getid3->info['audio']['channels'] = $info_ac3['num_channels'];
119
120			$offset = 11;
121
122			if ($info_ac3_raw_bsi['acmod'] & 0x01) {
123			// If the lsb of acmod is a 1, center channel is in use and cmixlev follows in the bit stream.
124			$info_ac3_raw_bsi['cmixlev'] = bindec(substr($ac3_header['bsi'], $offset, 2));
125			$info_ac3['center_mix_level'] = getid3_ac3::AC3centerMixLevelLookup($info_ac3_raw_bsi['cmixlev']);
126			$offset += 2;
127			}
128
129			if ($info_ac3_raw_bsi['acmod'] & 0x04) {
130			// If the msb of acmod is a 1, surround channels are in use and surmixlev follows in the bit stream.
131			$info_ac3_raw_bsi['surmixlev'] = bindec(substr($ac3_header['bsi'], $offset, 2));
132			$info_ac3['surround_mix_level'] = getid3_ac3::AC3surroundMixLevelLookup($info_ac3_raw_bsi['surmixlev']);
133			$offset += 2;
134			}
135
136			if ($info_ac3_raw_bsi['acmod'] == 0x02) {
137			// When operating in the two channel mode, this 2-bit code indicates whether or not the program has been encoded in Dolby Surround.
138			$info_ac3_raw_bsi['dsurmod'] = bindec(substr($ac3_header['bsi'], $offset, 2));
139			$info_ac3['dolby_surround_mode'] = getid3_ac3::AC3dolbySurroundModeLookup($info_ac3_raw_bsi['dsurmod']);
140			$offset += 2;
141			}
142
143			$info_ac3_raw_bsi['lfeon'] = $ac3_header['bsi']{$offset++} == '1';
144			$info_ac3['lfe_enabled'] = $info_ac3_raw_bsi['lfeon'];
145			if ($info_ac3_raw_bsi['lfeon']) {
146			$getid3->info['audio']['channels'] .= '.1';
147			}
148
149			$info_ac3['channels_enabled'] = getid3_ac3::AC3channelsEnabledLookup($info_ac3_raw_bsi['acmod'], $info_ac3_raw_bsi['lfeon']);
150
151			// This indicates how far the average dialogue level is below digital 100 percent. Valid values are 1�31.
152			// 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.
153			$info_ac3_raw_bsi['dialnorm'] = bindec(substr($ac3_header['bsi'], $offset, 5));
154			$offset += 5;
155			$info_ac3['dialogue_normalization'] = '-'.$info_ac3_raw_bsi['dialnorm'].'dB';
156
157			$info_ac3_raw_bsi['compre_flag'] = $ac3_header['bsi']{$offset++} == '1';
158			if ($info_ac3_raw_bsi['compre_flag']) {
159			$info_ac3_raw_bsi['compr'] = bindec(substr($ac3_header['bsi'], $offset, 8));
160			$offset += 8;
161
162			$info_ac3['heavy_compression'] = getid3_ac3::AC3heavyCompression($info_ac3_raw_bsi['compr']);
163			}
164
165			$info_ac3_raw_bsi['langcode_flag'] = $ac3_header['bsi']{$offset++} == '1';
166			if ($info_ac3_raw_bsi['langcode_flag']) {
167			$info_ac3_raw_bsi['langcod'] = bindec(substr($ac3_header['bsi'], $offset, 8));
168			$offset += 8;
169			}
170
171			$info_ac3_raw_bsi['audprodie'] = $ac3_header['bsi']{$offset++} == '1';
172			if ($info_ac3_raw_bsi['audprodie']) {
173			$info_ac3_raw_bsi['mixlevel'] = bindec(substr($ac3_header['bsi'], $offset, 5));
174			$offset += 5;
175
176			$info_ac3_raw_bsi['roomtyp'] = bindec(substr($ac3_header['bsi'], $offset, 2));
177			$offset += 2;
178
179			$info_ac3['mixing_level'] = (80 + $info_ac3_raw_bsi['mixlevel']).'dB';
180			$info_ac3['room_type'] = getid3_ac3::AC3roomTypeLookup($info_ac3_raw_bsi['roomtyp']);
181			}
182
183			if ($info_ac3_raw_bsi['acmod'] == 0x00) {
184			// If acmod is 0, then two completely independent program channels (dual mono)
185			// are encoded into the bit stream, and are referenced as Ch1, Ch2. In this case,
186			// a number of additional items are present in BSI or audblk to fully describe Ch2.
187
188
189			// This indicates how far the average dialogue level is below digital 100 percent. Valid values are 1�31.
190			// 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.
191			$info_ac3_raw_bsi['dialnorm2'] = bindec(substr($ac3_header['bsi'], $offset, 5));
192			$offset += 5;
193
194			$info_ac3['dialogue_normalization2'] = '-'.$info_ac3_raw_bsi['dialnorm2'].'dB';
195
196			$info_ac3_raw_bsi['compre_flag2'] = $ac3_header['bsi']{$offset++} == '1';
197			if ($info_ac3_raw_bsi['compre_flag2']) {
198			$info_ac3_raw_bsi['compr2'] = bindec(substr($ac3_header['bsi'], $offset, 8));
199			$offset += 8;
200
201			$info_ac3['heavy_compression2'] = getid3_ac3::AC3heavyCompression($info_ac3_raw_bsi['compr2']);
202			}
203
204			$info_ac3_raw_bsi['langcode_flag2'] = $ac3_header['bsi']{$offset++} == '1';
205			if ($info_ac3_raw_bsi['langcode_flag2']) {
206			$info_ac3_raw_bsi['langcod2'] = bindec(substr($ac3_header['bsi'], $offset, 8));
207			$offset += 8;
208			}
209
210			$info_ac3_raw_bsi['audprodie2'] = $ac3_header['bsi']{$offset++} == '1';
211			if ($info_ac3_raw_bsi['audprodie2']) {
212			$info_ac3_raw_bsi['mixlevel2'] = bindec(substr($ac3_header['bsi'], $offset, 5));
213			$offset += 5;
214
215			$info_ac3_raw_bsi['roomtyp2'] = bindec(substr($ac3_header['bsi'], $offset, 2));
216			$offset += 2;
217
218			$info_ac3['mixing_level2'] = (80 + $info_ac3_raw_bsi['mixlevel2']).'dB';
219			$info_ac3['room_type2'] = getid3_ac3::AC3roomTypeLookup($info_ac3_raw_bsi['roomtyp2']);
220			}
221
222			}
223
224			$info_ac3_raw_bsi['copyright'] = $ac3_header['bsi']{$offset++} == '1';
225
226			$info_ac3_raw_bsi['original'] = $ac3_header['bsi']{$offset++} == '1';
227
228			$info_ac3_raw_bsi['timecode1_flag'] = $ac3_header['bsi']{$offset++} == '1';
229			if ($info_ac3_raw_bsi['timecode1_flag']) {
230			$info_ac3_raw_bsi['timecode1'] = bindec(substr($ac3_header['bsi'], $offset, 14));
231			$offset += 14;
232			}
233
234			$info_ac3_raw_bsi['timecode2_flag'] = $ac3_header['bsi']{$offset++} == '1';
235			if ($info_ac3_raw_bsi['timecode2_flag']) {
236			$info_ac3_raw_bsi['timecode2'] = bindec(substr($ac3_header['bsi'], $offset, 14));
237			$offset += 14;
238			}
239
240			$info_ac3_raw_bsi['addbsi_flag'] = $ac3_header['bsi']{$offset++} == '1';
241			if ($info_ac3_raw_bsi['addbsi_flag']) {
242			$info_ac3_raw_bsi['addbsi_length'] = bindec(substr($ac3_header['bsi'], $offset, 6));
243			$offset += 6;
244
245			$ac3_header['bsi'] .= getid3_lib::BigEndian2Bin($this->fread($info_ac3_raw_bsi['addbsi_length']));
246
247			$info_ac3_raw_bsi['addbsi_data'] = substr($ac3_header['bsi'], 119, $info_ac3_raw_bsi['addbsi_length'] * 8);
248			}
249
250			return true;
251			}
252
253
254
255			public static function AC3sampleRateCodeLookup($fscod) {
256
257			static $lookup = array (
258			0 => 48000,
259			1 => 44100,
260			2 => 32000,
261			3 => 'reserved' // If the reserved code is indicated, the decoder should not attempt to decode audio and should mute.
262			);
263			return (isset($lookup[$fscod]) ? $lookup[$fscod] : false);
264			}
265
266
267
268			public static function AC3serviceTypeLookup($bsmod, $acmod) {
269
270			static $lookup = array (
271			0 => 'main audio service: complete main (CM)',
272			1 => 'main audio service: music and effects (ME)',
273			2 => 'associated service: visually impaired (VI)',
274			3 => 'associated service: hearing impaired (HI)',
275			4 => 'associated service: dialogue (D)',
276			5 => 'associated service: commentary (C)',
277			6 => 'associated service: emergency (E)',
278			7 => 'main audio service: karaoke'
279			);
280
281			if ($bsmod == 7 && $acmod == 1) {
282			return 'associated service: voice over (VO)';
283			}
284
285			return (isset($lookup[$bsmod]) ? $lookup[$bsmod] : false);
286			}
287
288
289
290			public static function AC3audioCodingModeLookup($acmod) {
291
292			// array (channel configuration, # channels (not incl LFE), channel order)
293			static $lookup = array (
294			0 => array ('channel_config'=>'1+1', 'num_channels'=>2, 'channel_order'=>'Ch1,Ch2'),
295			1 => array ('channel_config'=>'1/0', 'num_channels'=>1, 'channel_order'=>'C'),
296			2 => array ('channel_config'=>'2/0', 'num_channels'=>2, 'channel_order'=>'L,R'),
297			3 => array ('channel_config'=>'3/0', 'num_channels'=>3, 'channel_order'=>'L,C,R'),
298			4 => array ('channel_config'=>'2/1', 'num_channels'=>3, 'channel_order'=>'L,R,S'),
299			5 => array ('channel_config'=>'3/1', 'num_channels'=>4, 'channel_order'=>'L,C,R,S'),
300			6 => array ('channel_config'=>'2/2', 'num_channels'=>4, 'channel_order'=>'L,R,SL,SR'),
301			7 => array ('channel_config'=>'3/2', 'num_channels'=>5, 'channel_order'=>'L,C,R,SL,SR')
302			);
303			return (isset($lookup[$acmod]) ? $lookup[$acmod] : false);
304			}
305
306
307
308			public static function AC3centerMixLevelLookup($cmixlev) {
309
310			static $lookup;
311			if (!@$lookup) {
312			$lookup = array (
313			0 => pow(2, -3.0 / 6), // 0.707 (�3.0 dB)
314			1 => pow(2, -4.5 / 6), // 0.595 (�4.5 dB)
315			2 => pow(2, -6.0 / 6), // 0.500 (�6.0 dB)
316			3 => 'reserved'
317			);
318			}
319			return (isset($lookup[$cmixlev]) ? $lookup[$cmixlev] : false);
320			}
321
322
323
324			public static function AC3surroundMixLevelLookup($surmixlev) {
325
326			static $lookup;
327			if (!@$lookup) {
328			$lookup = array (
329			0 => pow(2, -3.0 / 6),
330			1 => pow(2, -6.0 / 6),
331			2 => 0,
332			3 => 'reserved'
333			);
334			}
335			return (isset($lookup[$surmixlev]) ? $lookup[$surmixlev] : false);
336			}
337
338
339
340			public static function AC3dolbySurroundModeLookup($dsurmod) {
341
342			static $lookup = array (
343			0 => 'not indicated',
344			1 => 'Not Dolby Surround encoded',
345			2 => 'Dolby Surround encoded',
346			3 => 'reserved'
347			);
348			return (isset($lookup[$dsurmod]) ? $lookup[$dsurmod] : false);
349			}
350
351
352
353			public static function AC3channelsEnabledLookup($acmod, $lfeon) {
354
355			return array (
356			'ch1' => $acmod == 0,
357			'ch2' => $acmod == 0,
358			'left' => $acmod > 1,
359			'right' => $acmod > 1,
360			'center' => (bool)($acmod & 0x01),
361			'surround_mono' => $acmod == 4 \|\| $acmod == 5,
362			'surround_left' => $acmod == 6 \|\| $acmod == 7,
363			'surround_right' => $acmod == 6 \|\| $acmod == 7,
364			'lfe' => $lfeon
365			);
366			}
367
368
369
370			public static function AC3heavyCompression($compre) {
371
372			// The first four bits indicate gain changes in 6.02dB increments which can be
373			// implemented with an arithmetic shift operation. The following four bits
374			// indicate linear gain changes, and require a 5-bit multiply.
375			// We will represent the two 4-bit fields of compr as follows:
376			// X0 X1 X2 X3 . Y4 Y5 Y6 Y7
377			// The meaning of the X values is most simply described by considering X to represent a 4-bit
378			// signed integer with values from �8 to +7. The gain indicated by X is then (X + 1) * 6.02 dB. The
379			// following table shows this in detail.
380
381			// Meaning of 4 msb of compr
382			// 7 +48.16 dB
383			// 6 +42.14 dB
384			// 5 +36.12 dB
385			// 4 +30.10 dB
386			// 3 +24.08 dB
387			// 2 +18.06 dB
388			// 1 +12.04 dB
389			// 0 +6.02 dB
390			// -1 0 dB
391			// -2 �6.02 dB
392			// -3 �12.04 dB
393			// -4 �18.06 dB
394			// -5 �24.08 dB
395			// -6 �30.10 dB
396			// -7 �36.12 dB
397			// -8 �42.14 dB
398
399			$fourbit = str_pad(decbin(($compre & 0xF0) >> 4), 4, '0', STR_PAD_LEFT);
400			if ($fourbit{0} == '1') {
401			$log_gain = -8 + bindec(substr($fourbit, 1));
402			} else {
403			$log_gain = bindec(substr($fourbit, 1));
404			}
405			$log_gain = ($log_gain + 1) * (20 * log10(2));
406
407			// The value of Y is a linear representation of a gain change of up to �6 dB. Y is considered to
408			// be an unsigned fractional integer, with a leading value of 1, or: 0.1 Y4 Y5 Y6 Y7 (base 2). Y can
409			// represent values between 0.111112 (or 31/32) and 0.100002 (or 1/2). Thus, Y can represent gain
410			// changes from �0.28 dB to �6.02 dB.
411
412			$lin_gain = (16 + ($compre & 0x0F)) / 32;
413
414			// The combination of X and Y values allows compr to indicate gain changes from
415			// 48.16 � 0.28 = +47.89 dB, to
416			// �42.14 � 6.02 = �48.16 dB.
417
418			return $log_gain - $lin_gain;
419			}
420
421
422
423			public static function AC3roomTypeLookup($roomtyp) {
424
425			static $lookup = array (
426			0 => 'not indicated',
427			1 => 'large room, X curve monitor',
428			2 => 'small room, flat monitor',
429			3 => 'reserved'
430			);
431			return (isset($lookup[$roomtyp]) ? $lookup[$roomtyp] : false);
432			}
433
434
435
436			public static function AC3frameSizeLookup($frmsizecod, $fscod) {
437
438			$padding = (bool)($frmsizecod % 2);
439			$frame_size_id = floor($frmsizecod / 2);
440
441			static $lookup = array (
442			0 => array (128, 138, 192),
443			1 => array (40, 160, 174, 240),
444			2 => array (48, 192, 208, 288),
445			3 => array (56, 224, 242, 336),
446			4 => array (64, 256, 278, 384),
447			5 => array (80, 320, 348, 480),
448			6 => array (96, 384, 416, 576),
449			7 => array (112, 448, 486, 672),
450			8 => array (128, 512, 556, 768),
451			9 => array (160, 640, 696, 960),
452			10 => array (192, 768, 834, 1152),
453			11 => array (224, 896, 974, 1344),
454			12 => array (256, 1024, 1114, 1536),
455			13 => array (320, 1280, 1392, 1920),
456			14 => array (384, 1536, 1670, 2304),
457			15 => array (448, 1792, 1950, 2688),
458			16 => array (512, 2048, 2228, 3072),
459			17 => array (576, 2304, 2506, 3456),
460			18 => array (640, 2560, 2786, 3840)
461			);
462			if (($fscod == 1) && $padding) {
463			// frame lengths are padded by 1 word (16 bits) at 44100
464			$lookup[$frmsizecod] += 2;
465			}
466			return (isset($lookup[$frame_size_id][$fscod]) ? $lookup[$frame_size_id][$fscod] : false);
467			}
468
469
470
471			public static function AC3bitrateLookup($frmsizecod) {
472
473			static $lookup = array (
474			0 => 32000,
475			1 => 40000,
476			2 => 48000,
477			3 => 56000,
478			4 => 64000,
479			5 => 80000,
480			6 => 96000,
481			7 => 112000,
482			8 => 128000,
483			9 => 160000,
484			10 => 192000,
485			11 => 224000,
486			12 => 256000,
487			13 => 320000,
488			14 => 384000,
489			15 => 448000,
490			16 => 512000,
491			17 => 576000,
492			18 => 640000
493			);
494			$frame_size_id = floor($frmsizecod / 2);
495			return (isset($lookup[$frame_size_id]) ? $lookup[$frame_size_id] : false);
496			}
497
498			}
499
500			?>
			0 ignored issues – show Best Practice introduced 2020-01-01 02:01 UTC by Report Bug Copy Issue Report It is not recommended to use PHP's closing tag `?>` in files other than templates. Using a closing tag in PHP files that only contain PHP code is not recommended as you might accidentally add whitespace after the closing tag which would then be output by PHP. This can cause severe problems, for example headers cannot be sent anymore. A simple precaution is to leave off the closing tag as it is not required, and it also has no negative effects whatsoever. Loading history...

mambax7 / xoopseditors

Branch — master (f2d2e3)

getid3_ac3::AC3sampleRateCodeLookup() A

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