La.php

Go to the documentation of this file.

<?php

namespace GetId3\Module\Audio;

use GetId3\Handler\BaseHandler;
use GetId3\Lib\Helper;
use GetId3\GetId3Core;
use GetId3\Module\AudioVideo\Riff;

//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
// See readme.txt for more details                             //
//                                                             //
// module.audio.la.php                                         //
// module for analyzing LA (LosslessAudio) audio files         //
// dependencies: module.audio.riff.php                         //
//                                                            ///

class La extends BaseHandler
{

    public function analyze()
    {
        $info = &$this->getid3->info;

        $offset = 0;
        fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
        $rawdata = fread($this->getid3->fp, $this->getid3->fread_buffer_size());

        switch (substr($rawdata, $offset, 4)) {
            case 'LA02':
            case 'LA03':
            case 'LA04':
                $info['fileformat']          = 'la';
                $info['audio']['dataformat'] = 'la';
                $info['audio']['lossless']   = true;

                $info['la']['version_major'] = (int) substr($rawdata, $offset + 2, 1);
                $info['la']['version_minor'] = (int) substr($rawdata, $offset + 3, 1);
                $info['la']['version']       = (float) $info['la']['version_major'] + ($info['la']['version_minor'] / 10);
                $offset += 4;

                $info['la']['uncompressed_size'] = Helper::LittleEndian2Int(substr($rawdata, $offset, 4));
                $offset += 4;
                if ($info['la']['uncompressed_size'] == 0) {
                    $info['error'][] = 'Corrupt LA file: uncompressed_size == zero';

                    return false;
                }

                $WAVEchunk = substr($rawdata, $offset, 4);
                if ($WAVEchunk !== 'WAVE') {
                    $info['error'][] = 'Expected "WAVE" ('.Helper::PrintHexBytes('WAVE').') at offset '.$offset.', found "'.$WAVEchunk.'" ('.Helper::PrintHexBytes($WAVEchunk).') instead.';

                    return false;
                }
                $offset += 4;

                $info['la']['fmt_size'] = 24;
                if ($info['la']['version'] >= 0.3) {

                    $info['la']['fmt_size']    = Helper::LittleEndian2Int(substr($rawdata, $offset, 4));
                    $info['la']['header_size'] = 49 + $info['la']['fmt_size'] - 24;
                    $offset += 4;

                } else {

                    // version 0.2 didn't support additional data blocks
                    $info['la']['header_size'] = 41;

                }

                $fmt_chunk = substr($rawdata, $offset, 4);
                if ($fmt_chunk !== 'fmt ') {
                    $info['error'][] = 'Expected "fmt " ('.Helper::PrintHexBytes('fmt ').') at offset '.$offset.', found "'.$fmt_chunk.'" ('.Helper::PrintHexBytes($fmt_chunk).') instead.';

                    return false;
                }
                $offset += 4;
                $fmt_size = Helper::LittleEndian2Int(substr($rawdata, $offset, 4));
                $offset += 4;

                $info['la']['raw']['format']  = Helper::LittleEndian2Int(substr($rawdata, $offset, 2));
                $offset += 2;

                $info['la']['channels']       = Helper::LittleEndian2Int(substr($rawdata, $offset, 2));
                $offset += 2;
                if ($info['la']['channels'] == 0) {
                    $info['error'][] = 'Corrupt LA file: channels == zero';

                        return false;
                }

                $info['la']['sample_rate'] = Helper::LittleEndian2Int(substr($rawdata, $offset, 4));
                $offset += 4;
                if ($info['la']['sample_rate'] == 0) {
                    $info['error'][] = 'Corrupt LA file: sample_rate == zero';

                        return false;
                }

                $info['la']['bytes_per_second']     = Helper::LittleEndian2Int(substr($rawdata, $offset, 4));
                $offset += 4;
                $info['la']['bytes_per_sample']     = Helper::LittleEndian2Int(substr($rawdata, $offset, 2));
                $offset += 2;
                $info['la']['bits_per_sample']      = Helper::LittleEndian2Int(substr($rawdata, $offset, 2));
                $offset += 2;

                $info['la']['samples']              = Helper::LittleEndian2Int(substr($rawdata, $offset, 4));
                $offset += 4;

                $info['la']['raw']['flags']         = Helper::LittleEndian2Int(substr($rawdata, $offset, 1));
                $offset += 1;
                $info['la']['flags']['seekable']             = (bool) ($info['la']['raw']['flags'] & 0x01);
                if ($info['la']['version'] >= 0.4) {
                    $info['la']['flags']['high_compression'] = (bool) ($info['la']['raw']['flags'] & 0x02);
                }

                $info['la']['original_crc']         = Helper::LittleEndian2Int(substr($rawdata, $offset, 4));
                $offset += 4;

                // mikeØbevin*de
                // Basically, the blocksize/seekevery are 61440/19 in La0.4 and 73728/16
                // in earlier versions. A seekpoint is added every blocksize * seekevery
                // samples, so 4 * int(totalSamples / (blockSize * seekEvery)) should
                // give the number of bytes used for the seekpoints. Of course, if seeking
                // is disabled, there are no seekpoints stored.
                if ($info['la']['version'] >= 0.4) {
                    $info['la']['blocksize'] = 61440;
                    $info['la']['seekevery'] = 19;
                } else {
                    $info['la']['blocksize'] = 73728;
                    $info['la']['seekevery'] = 16;
                }

                $info['la']['seekpoint_count'] = 0;
                if ($info['la']['flags']['seekable']) {
                    $info['la']['seekpoint_count'] = floor($info['la']['samples'] / ($info['la']['blocksize'] * $info['la']['seekevery']));

                    for ($i = 0; $i < $info['la']['seekpoint_count']; $i++) {
                        $info['la']['seekpoints'][] = Helper::LittleEndian2Int(substr($rawdata, $offset, 4));
                        $offset += 4;
                    }
                }

                if ($info['la']['version'] >= 0.3) {

                    // Following the main header information, the program outputs all of the
                    // seekpoints. Following these is what I called the 'footer start',
                    // i.e. the position immediately after the La audio data is finished.
                    $info['la']['footerstart'] = Helper::LittleEndian2Int(substr($rawdata, $offset, 4));
                    $offset += 4;

                    if ($info['la']['footerstart'] > $info['filesize']) {
                        $info['warning'][] = 'FooterStart value points to offset '.$info['la']['footerstart'].' which is beyond end-of-file ('.$info['filesize'].')';
                        $info['la']['footerstart'] = $info['filesize'];
                    }

                } else {

                    // La v0.2 didn't have FooterStart value
                    $info['la']['footerstart'] = $info['avdataend'];

                }

                if ($info['la']['footerstart'] < $info['avdataend']) {
                    if ($RIFFtempfilename = tempnam(GetId3Core::getTempDir(), 'id3')) {
                        if ($RIFF_fp = fopen($RIFFtempfilename, 'w+b')) {
                            $RIFFdata = 'WAVE';
                            if ($info['la']['version'] == 0.2) {
                                $RIFFdata .= substr($rawdata, 12, 24);
                            } else {
                                $RIFFdata .= substr($rawdata, 16, 24);
                            }
                            if ($info['la']['footerstart'] < $info['avdataend']) {
                                fseek($this->getid3->fp, $info['la']['footerstart'], SEEK_SET);
                                $RIFFdata .= fread($this->getid3->fp, $info['avdataend'] - $info['la']['footerstart']);
                            }
                            $RIFFdata = 'RIFF'.Helper::LittleEndian2String(strlen($RIFFdata), 4, false).$RIFFdata;
                            fwrite($RIFF_fp, $RIFFdata, strlen($RIFFdata));
                            fclose($RIFF_fp);

                            $getid3_temp = new GetId3Core();
                            $getid3_temp->openfile($RIFFtempfilename);
                            $getid3_riff = new Riff($getid3_temp);
                            $getid3_riff->analyze();

                            if (empty($getid3_temp->info['error'])) {
                                $info['riff'] = $getid3_temp->info['riff'];
                            } else {
                                $info['warning'][] = 'Error parsing RIFF portion of La file: '.implode($getid3_temp->info['error']);
                            }
                            unset($getid3_temp, $getid3_riff);
                        }
                        unlink($RIFFtempfilename);
                    }
                }

                // $info['avdataoffset'] should be zero to begin with, but just in case it's not, include the addition anyway
                $info['avdataend']    = $info['avdataoffset'] + $info['la']['footerstart'];
                $info['avdataoffset'] = $info['avdataoffset'] + $offset;

                //$info['la']['codec']                = RIFFwFormatTagLookup($info['la']['raw']['format']);
                $info['la']['compression_ratio']    = (float) (($info['avdataend'] - $info['avdataoffset']) / $info['la']['uncompressed_size']);
                $info['playtime_seconds']           = (float) ($info['la']['samples'] / $info['la']['sample_rate']) / $info['la']['channels'];
                if ($info['playtime_seconds'] == 0) {
                    $info['error'][] = 'Corrupt LA file: playtime_seconds == zero';

                    return false;
                }

                $info['audio']['bitrate']            = ($info['avdataend'] - $info['avdataoffset']) * 8 / $info['playtime_seconds'];
                //$info['audio']['codec']              = $info['la']['codec'];
                $info['audio']['bits_per_sample']    = $info['la']['bits_per_sample'];
                break;

            default:
                if (substr($rawdata, $offset, 2) == 'LA') {
                    $info['error'][] = 'This version of GetId3Core() ['.$this->getid3->version().'] does not support LA version '.substr($rawdata, $offset + 2, 1).'.'.substr($rawdata, $offset + 3, 1).' which this appears to be - check http://getid3.sourceforge.net for updates.';
                } else {
                    $info['error'][] = 'Not a LA (Lossless-Audio) file';
                }

                return false;
                break;
        }

        $info['audio']['channels']    = $info['la']['channels'];
        $info['audio']['sample_rate'] = (int) $info['la']['sample_rate'];
        $info['audio']['encoder']     = 'LA v'.$info['la']['version'];

        return true;
    }

}