PHP获取音频文件的相关信息
发布:smiling 来源: PHP粉丝网 添加日期:2021-06-02 10:09:27 浏览: 评论:0
项目需求:现在有一个音频文件上传的功能,在上传后PHP需要获取这个音频文件的相关信息,例如:时长等,由于这个文件是放在买的空间上的,没有像ffmpeg这样的扩展来处理,那么PHP能不能获取到这些信息?
下面是之前在项目中用到的一个用PHP进行音频文件头部信息的读取与写入操作的实现,主要针对 WMA 和 MP3 两种格式,供参考。
- <?php
- // AudioExif.class.php
- // 用PHP进行音频文件头部信息的读取与写入
- // 目前只支持 WMA 和 MP3 两种格式, 只支持常用的几个头部信息
- //
- // 写入信息支持: Title(名称), Artist(艺术家), Copyright(版权), Description (描述)
- // Year(年代), Genre (流派), AlbumTitle (专辑标题)
- // 其中 mp3 和 wma 略有不同, 具体返回的信息还可能更多, 但只有以上信息可以被写入
- // mp3 还支持 Track (曲目编号写入)
- // 对于 MP3 文件支持 ID3v1也支持ID3v2, 读取时优先 v2, 写入时总是会写入v1, 必要时写入v2
- //
- // 用法说明: (由于 wma 使用 Unicode 存取, 故还需要 mb_convert_encoding() 扩展
- // 返回数据及写入数据均为 ANSI 编码, 即存什么就显示什么 (中文_GB2312)
- //
- // require ('AudioExif.class.php');
- // $AE = new AudioExif;
- // $file = '/path/to/test.mp3';
- //
- // 1. 检查文件是否完整 (only for wma, mp3始终返回 true)
- //
- // $AE->CheckSize($file);
- //
- // 2. 读取信息, 返回值由信息组成的数组, 键名解释参见上方
- //
- // print_r($AE->GetInfo($file));
- //
- // 3. 写入信息, 第二参数是一个哈希数组, 键->值, 支持的参见上方的, mp3也支持 Track
- // 要求第一参数的文件路径可由本程序写入
- // $pa = array('Title' => '新标题', 'AlbumTitle' => '新的专辑名称');
- // $AE->SetInfo($file, $pa);
- //
- // 其它: 该插件花了不少时间搜集查找 wma及mp3 的文件格式说明文档与网页, 希望对大家有用.
- // 其实网上已经有不少类似的程序, 但对 wma 实在太少了, 只能在 win 平台下通过 M$ 的
- // API 来操作, 而 MP3 也很少有可以在 unix/linux 命令行操作的, 所以特意写了这个模块
- //
- // 如果发现 bug 或提交 patch, 或加以改进使它更加健壮, 请告诉我.
- // (关于 ID3和Wma的文件格式及结构 在网上应该都可以找到参考资料)
- //
- if (!extension_loaded('mbstring')){
- trigger_error('PHP Extension module `mbstring` is required for AudioExif', E_USER_WARNING);
- return true;
- }
- // the Main Class
- class AudioExif{
- // public vars
- var $_wma = false;
- var $_mp3 = false;
- // Construct
- function AudioExif() {
- // nothing to do
- }
- // check the filesize
- function CheckSize($file) {
- $handler = &$this->_get_handler($file);
- if (!$handler) return false;
- return $handler->check_size($file);
- }
- // get the infomations
- function GetInfo($file) {
- $handler = &$this->_get_handler($file);
- if (!$handler) return false;
- return $handler->get_info($file);
- }
- // write the infomations
- function SetInfo($file, $pa) {
- if (!is_writable($file)) {
- trigger_error('AudioExif: file `' . $file . '` can not been overwritten', E_USER_WARNING);
- return false;
- }
- $handler = &$this->_get_handler($file);
- if (!$handler) return false;
- return $handler->set_info($file, $pa);
- }
- // private methods
- function &_get_handler($file) {
- $ext = strtolower(strrchr($file, '.'));
- $ret = false;
- if ($ext == '.mp3') {
- // MP3
- $ret = &$this->_mp3;
- if (!$ret) $ret = new _Mp3Exif();
- }
- else if ($ext == '.wma')
- { // wma
- $ret = &$this->_wma;
- if (!$ret) $ret = new _WmaExif();
- }
- else
- { // unknown
- trigger_error('AudioExif not supported `' . $ext . '` file.', E_USER_WARNING);
- }
- return $ret;
- }
- }
- // DBCS => gb2312
- function dbcs_gbk($str)
- {
- // strip the last "\0\0"
- $str = substr($str, 0, -2);
- return mb_convert_encoding($str, 'GBK', 'UCS-2LE');
- }
- // gb2312 => DBCS
- function gbk_dbcs($str)
- {
- $str = mb_convert_encoding($str, 'UCS-2LE', 'GBK');
- $str .= "\0\0";
- return $str;
- }
- // file exif
- class _AudioExif
- {
- var $fd;
- var $head;
- var $head_off;
- var $head_buf;
- // init the file handler
- function _file_init($fpath, $write = false)
- {
- $mode = ($write ? 'rb+' : 'rb');
- $this->fd = @fopen($fpath, $mode);
- if (!$this->fd)
- {
- trigger_error('AudioExif: `' . $fpath . '` can not be opened with mode `' . $mode . '`', E_USER_WARNING);
- return false;
- }
- $this->head = false;
- $this->head_off = 0;
- $this->head_buf = '';
- return true;
- }
- // read buffer from the head_buf & move the off pointer
- function _read_head_buf($len)
- {
- if ($len <= 0) return NULL;
- $buf = substr($this->head_buf, $this->head_off, $len);
- $this->head_off += strlen($buf);
- return $buf;
- }
- // read one short value
- function _read_head_short()
- {
- $ord1 = ord(substr($this->head_buf, $this->head_off, 1));
- $ord2 = ord(substr($this->head_buf, $this->head_off+1, 1));
- $this->head_off += 2;
- return ($ord1 + ($ord2<<8));
- }
- // save the file head
- function _file_save($head, $olen, $nlen = 0)
- {
- if ($nlen == 0) $nlen = strlen($head);
- if ($nlen == $olen)
- {
- // shorter
- flock($this->fd, LOCK_EX);
- fseek($this->fd, 0, SEEK_SET);
- fwrite($this->fd, $head, $nlen);
- flock($this->fd, LOCK_UN);
- }
- else
- {
- // longer, buffer required
- $stat = fstat($this->fd);
- $fsize = $stat['size'];
- // buf required (4096?) 应该不会 nlen - olen > 4096 吧
- $woff = 0;
- $roff = $olen;
- // read first buffer
- flock($this->fd, LOCK_EX);
- fseek($this->fd, $roff, SEEK_SET);
- $buf = fread($this->fd, 4096);
- // seek to start
- fseek($this->fd, $woff, SEEK_SET);
- fwrite($this->fd, $head, $nlen);
- $woff += $nlen;
- // seek to woff & write the data
- do
- {
- $buf2 = $buf;
- $roff += 4096;
- if ($roff < $fsize)
- {
- fseek($this->fd, $roff, SEEK_SET);
- $buf = fread($this->fd, 4096);
- }
- // save last buffer
- $len2 = strlen($buf2);
- fseek($this->fd, $woff, SEEK_SET);
- fwrite($this->fd, $buf2, $len2);
- $woff += $len2;
- }
- while ($roff < $fsize);
- ftruncate($this->fd, $woff);
- flock($this->fd, LOCK_UN);
- }
- }
- // close the file
- function _file_deinit()
- {
- if ($this->fd)
- {
- fclose($this->fd);
- $this->fd = false;
- }
- }
- }
- // wma class
- class _WmaExif extends _AudioExif
- {
- var $items1 = array('Title', 'Artist', 'Copyright', 'Description', 'Reserved');
- var $items2 = array('Year', 'Genre', 'AlbumTitle');
- // check file size (length) maybe invalid file
- function check_size($file)
- {
- $ret = false;
- if (!$this->_file_init($file)) return true;
- if ($this->_init_header())
- {
- $buf = fread($this->fd, 24);
- $tmp = unpack('H32id/Vlen/H8unused', $buf);
- if ($tmp['id'] == '3626b2758e66cf11a6d900aa0062ce6c')
- {
- $stat = fstat($this->fd);
- $ret = ($stat['size'] == ($this->head['len'] + $tmp['len']));
- }
- }
- $this->_file_deinit();
- return $ret;
- }
- // set info (save the infos)
- function set_info($file, $pa)
- {
- // check the pa
- settype($pa, 'array');
- if (!$this->_file_init($file, true)) return false;
- if (!$this->_init_header())
- {
- $this->_file_deinit();
- return false;
- }
- // parse the old header & generate the new header
- $head_body = '';
- $st_found = $ex_found = false;
- $head_num = $this->head['num'];
- while (($tmp = $this->_get_head_frame()) && ($head_num > 0))
- {
- $head_num--;
- if ($tmp['id'] == '3326b2758e66cf11a6d900aa0062ce6c')
- { // Standard Info
- // 1-4
- $st_found = true;
- $st_body1 = $st_body2 = '';
- $lenx = unpack('v5', $this->_read_head_buf(10));
- $tmp['len'] -= 34; // 10 + 24
- for ($i = 0; $i < count($this->items1); $i++)
- {
- $l = $lenx[$i+1];
- $k = $this->items1[$i];
- $tmp['len'] -= $l;
- $data = $this->_read_head_buf($l);
- if (isset($pa[$k])) $data = gbk_dbcs($pa[$k]);
- $st_body2 .= $data;
- $st_body1 .= pack('v', strlen($data));
- }
- // left length
- if ($tmp['len'] > 0) $st_body2 .= $this->_read_head_buf($tmp['len']);
- // save to head_body
- $head_body .= pack('H32VH8', $tmp['id'], strlen($st_body1 . $st_body2)+24, $tmp['unused']);
- $head_body .= $st_body1 . $st_body2;
- $st_body2 .= $data;
- }
- // save to head_body
- $head_body .= pack('H32Va4', '3326b2758e66cf11a6d900aa0062ce6c', strlen($st_body1 . $st_body2)+24, '');
- $head_body .= $st_body1 . $st_body2;
- $this->head['num']++;
- }
- // ex not found?
- if (!$ex_found)
- {
- $inum = 0;
- $et_body = '';
- foreach ($this->items2 as $k)
- {
- $nbuf = gbk_dbcs('WM/' . $k);
- $vbuf = (isset($pa[$k]) ? gbk_dbcs($pa[$k]) : "");
- $et_body .= pack('v', strlen($nbuf)) . $nbuf . pack('vv', 0, strlen($vbuf)) . $vbuf;
- $inum++;
- }
- $head_body .= pack('H32Va4v', '40a4d0d207e3d21197f000a0c95ea850', strlen($et_body)+26, '', $inum);
- $head_body .= $et_body;
- $this->head['num']++;
- }
- // after save
- $new_len = strlen($head_body) + 30;
- $old_len = $this->head['len'];
- if ($new_len < $old_len)
- {
- $head_body .= str_repeat("\0", $old_len - $new_len);
- $new_len = $old_len;
- }
- $tmp = $this->head;
- $head_buf = pack('H32VVVH4', $tmp['id'], $new_len, $tmp['len2'], $tmp['num'], $tmp['unused']);
- $head_buf .= $head_body;
- $this->_file_save($head_buf, $old_len, $new_len);
- // close the file & return
- $this->_file_deinit();
- return true;
- }
- // get info
- function get_info($file)
- {
- $ret = array();
- if (!$this->_file_init($file)) return false;
- if (!$this->_init_header())
- {
- $this->_file_deinit();
- return false;
- }
- // get the data from head_buf
- $head_num = $this->head['num']; // num of head_frame
- while (($tmp = $this->_get_head_frame()) && $head_num > 0)
- {
- $head_num--;
- if ($tmp['id'] == '3326b2758e66cf11a6d900aa0062ce6c')
- { // Standard Info
- $lenx = unpack('v*', $this->_read_head_buf(10));
- for ($i = 1; $i <= count($this->items1); $i++)
- {
- $k = $this->items1[$i-1];
- $ret[$k] = dbcs_gbk($this->_read_head_buf($lenx[$i]));
- }
- }
- else if ($tmp['id'] == '40a4d0d207e3d21197f000a0c95ea850')
- { // Extended Info
- $inum = $this->_read_head_short();
- $tmp['len'] -= 26;
- while ($inum > 0 && $tmp['len'] > 0)
- {
- // attribute name
- $nlen = $this->_read_head_short();
- $nbuf = $this->_read_head_buf($nlen);
- // the flag & value length
- $flag = $this->_read_head_short();
- $vlen = $this->_read_head_short();
- $vbuf = $this->_read_head_buf($vlen);
- // update the XX
- $tmp['len'] -= (6 + $nlen + $vlen);
- $inum--;
- $name = dbcs_gbk($nbuf);
- $k = substr($name, 3);
- if (in_array($k, $this->items2))
- { // all is string value (refer to falg for other tags)
- $ret[$k] = dbcs_gbk($vbuf);
- }
- }
- }
- else
- { // skip only
- if ($tmp['len'] > 24) $this->head_off += ($tmp['len'] - 24);
- }
- }
- $this->_file_deinit();
- return $ret;
- }
- // get the header?
- function _init_header()
- {
- fseek($this->fd, 0, SEEK_SET);
- $buf = fread($this->fd, 30);
- if (strlen($buf) != 30) return false;
- $tmp = unpack('H32id/Vlen/Vlen2/Vnum/H4unused', $buf);
- if ($tmp['id'] != '3026b2758e66cf11a6d900aa0062ce6c')
- return false;
- $this->head_buf = fread($this->fd, $tmp['len'] - 30);
- $this->head = $tmp;
- return true;
- }
- // _get_head_frame()
- function _get_head_frame()
- {
- $buf = $this->_read_head_buf(24);
- if (strlen($buf) != 24) return false;
- $tmp = unpack('H32id/Vlen/H8unused', $buf);
- return $tmp;
- }
- }
- // mp3 class (if not IDv2 then select IDv1)
- class _Mp3Exif extends _AudioExif
- {
- var $head1;
- var $genres = array('Blues','Classic Rock','Country','Dance','Disco','Funk','Grunge','Hip-Hop','Jazz','Metal','New Age','Oldies','Other','Pop','R&B','Rap','Reggae','Rock','Techno','Industrial','Alternative','Ska','Death Metal','Pranks','Soundtrack','Euro-Techno','Ambient','Trip-Hop','Vocal','Jazz+Funk','Fusion','Trance','Classical','Instrumental','Acid','House','Game','Sound Clip','Gospel','Noise','AlternRock','Bass','Soul','Punk','Space','Meditative','Instrumental Pop','Instrumental Rock','Ethnic','Gothic','Darkwave','Techno-Industrial','Electronic','Pop-Folk','Eurodance','Dream','Southern Rock','Comedy','Cult','Gangsta','Top 40','Christian Rap','Pop/Funk','Jungle','Native American','Cabaret','New Wave','Psychadelic','Rave','Showtunes','Trailer','Lo-Fi','Tribal','Acid Punk','Acid Jazz','Polka','Retro','Musical','Rock & Roll','Hard Rock','Unknown');
- // MP3 always return true
- function check_size($file)
- {
- return true;
- }
- // get info
- function get_info($file)
- {
- if (!$this->_file_init($file)) return false;
- $ret = false;
- if ($this->_init_header())
- {
- $ret = ($this->head ? $this->_get_v2_info() : $this->_get_v1_info());
- $ret['meta'] = $this->_get_meta_info();
- }
- $this->_file_deinit();
- return $ret;
- }
- // set info
- function set_info($file, $pa)
- {
- if (!$this->_file_init($file, true)) return false;
- if ($this->_init_header())
- {
- // always save v1 info
- $this->_set_v1_info($pa);
- // set v2 first if need
- $this->_set_v2_info($pa);
- }
- $this->_file_deinit();
- return true;
- }
- // get the header information[v1+v2], call after file_init
- function _init_header()
- {
- $this->head1 = false;
- $this->head = false;
- // try to get ID3v1 first
- fseek($this->fd, -128, SEEK_END);
- $buf = fread($this->fd, 128);
- if (strlen($buf) == 128 && substr($buf, 0, 3) == 'TAG')
- {
- $tmp = unpack('a3id/a30Title/a30Artist/a30AlbumTitle/a4Year/a28Description/CReserved/CTrack/CGenre', $buf);
- $this->head1 = $tmp;
- }
- // try to get ID3v2
- fseek($this->fd, 0, SEEK_SET);
- $buf = fread($this->fd, 10);
- if (strlen($buf) == 10 && substr($buf, 0, 3) == 'ID3')
- {
- $tmp = unpack('a3id/Cver/Crev/Cflag/C4size', $buf);
- $tmp['size'] = ($tmp['size1']<<21)|($tmp['size2']<<14)|($tmp['size3']<<7)|$tmp['size4'];
- unset($tmp['size1'], $tmp['size2'], $tmp['size3'], $tmp['size4']);
- $this->head = $tmp;
- $this->head_buf = fread($this->fd, $tmp['size']);
- }
- return ($this->head1 || $this->head);
- }
- // get v1 info
- function _get_v1_info()
- {
- $ret = array();
- $tmpa = array('Title', 'Artist', 'Copyright', 'Description', 'Year', 'AlbumTitle');
- foreach ($tmpa as $tmp)
- {
- $ret[$tmp] = $this->head1[$tmp];
- if ($pos = strpos($ret[$tmp], "\0"))
- $ret[$tmp] = substr($ret[$tmp], 0, $pos);
- }
- // count the Genre, [Track]
- if ($this->head1['Reserved'] == 0) $ret['Track'] = $this->head1['Track'];
- else $ret['Description'] .= chr($ret['Reserved']) . chr($ret['Track']);
- // Genre_idx
- $g = $this->head1['Genre'];
- if (!isset($this->genres[$g])) $ret['Genre'] = 'Unknown';
- else $ret['Genre'] = $this->genres[$g];
- // return the value
- $ret['ID3v1'] = 'yes';
- return $ret;
- }
- // get v2 info
- function _get_v2_info()
- {
- $ret = array();
- $items = array( 'TCOP'=>'Copyright', 'TPE1'=>'Artist', 'TIT2'=>'Title', 'TRCK'=> 'Track',
- 'TCON'=>'Genre', 'COMM'=>'Description', 'TYER'=>'Year', 'TALB'=>'AlbumTitle');
- while (true)
- {
- $buf = $this->_read_head_buf(10);
- if (strlen($buf) != 10) break;
- $tmp = unpack('a4fid/Nsize/nflag', $buf);
- if ($tmp['size'] == 0) break;
- $tmp['dat'] = $this->_read_head_buf($tmp['size']);
- // 0x6000 (11000000 00000000)
- if ($tmp['flag'] & 0x6000) continue;
- // mapping the data
- if ($k = $items[$tmp['fid']])
- { // If first char is "\0", just skip
- if (substr($tmp['dat'], 0, 1) == "\0") $tmp['dat'] = substr($tmp['dat'], 1);
- $ret[$k] = $tmp['dat'];
- }
- }
- // reset the genre
- if ($g = $ret['Genre'])
- {
- if (substr($g,0,1) == '(' && substr($g,-1,1) == ')') $g = substr($g, 1, -1);
- if (is_numeric($g))
- {
- $g = intval($g);
- $ret['Genre'] = (isset($this->genres[$g]) ? $this->genres[$g] : 'Unknown');
- }
- }
- $ret['ID3v1'] = 'no';
- return $ret;
- }
- // get meta info of MP3
- function _get_meta_info()
- {
- // seek to the lead buf: 0xff
- $off = 0;
- if ($this->head) $off = $this->head['size'] + 10;
- fseek($this->fd, $off, SEEK_SET);
- while (!feof($this->fd))
- {
- $skip = ord(fread($this->fd, 1));
- if ($skip == 0xff) break;
- }
- if ($skip != 0xff) return false;
- $buf = fread($this->fd, 3);
- if (strlen($buf) != 3) return false;
- $tmp = unpack('C3', $buf);
- if (($tmp[1] & 0xf0) != 0xf0) return false;
- // get the meta info
- $meta = array();
- // get mpeg version
- $meta['mpeg'] = ($tmp[1] & 0x08 ? 1 : 2);
- $meta['layer'] = ($tmp[1] & 0x04) ? (($tmp[1] & 0x02) ? 1 : 2) : (($tmp[1] & 0x02) ? 3 : 0);
- $meta['epro'] = ($tmp[1] & 0x01) ? 'no' : 'yes';
- // bit rates
- $bit_rates = array(
- 1 => array(
- 1 => array(0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,0),
- 2 => array(0,32,48,56,64,80,96,112,128,160,192,224,256,320,384,0),
- 3 => array(0,32,40,48,56,64,80,96,112,128,160,192,224,256,320,0)
- ),
- 2 => array(
- 1 => array(0,32,48,56,64,80,96,112,128,144,160,176,192,224,256,0),
- 2 => array(0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,0),
- 3 => array(0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,0)
- )
- );
- $i = $meta['mpeg'];
- $j = $meta['layer'];
- $k = ($tmp[2]>>4);
- $meta['bitrate'] = $bit_rates[$i][$j][$k];
- // sample rates <采样率>
- $sam_rates = array(1=>array(44100,48000,32000,0), 2=>array(22050,24000,16000,0));
- $meta['samrate'] = $sam_rates[$i][$k];
- $meta["padding"] = ($tmp[2] & 0x02) ? 'on' : 'off';
- $meta["private"] = ($tmp[2] & 0x01) ? 'on' : 'off';
- // mode & mode_ext
- $k = ($tmp[3]>>6);
- $channel_modes = array('stereo', 'joint stereo', 'dual channel', 'single channel');
- $meta['mode'] = $channel_modes[$k];
- $k = (($tmp[3]>>4) & 0x03);
- $extend_modes = array('MPG_MD_LR_LR', 'MPG_MD_LR_I', 'MPG_MD_MS_LR', 'MPG_MD_MS_I');
- $meta['ext_mode'] = $extend_modes[$k];
- $meta['copyright'] = ($tmp[3] & 0x08) ? 'yes' : 'no';
- $meta['original'] = ($tmp[3] & 0x04) ? 'yes' : 'no';
- $emphasis = array('none', '50/15 microsecs', 'rreserved', 'CCITT J 17');
- $k = ($tmp[3] & 0x03);
- $meta['emphasis'] = $emphasis[$k];
- return $meta;
- }
- // set v1 info
- function _set_v1_info($pa)
- {
- // ID3v1 (simpled)
- $off = -128;
- if (!($tmp = $this->head1))
- {
- $off = 0;
- $tmp['id'] = 'TAG';
- $tmp['Title'] = $tmp['Artist'] = $tmp['AlbumTitle'] = $tmp['Year'] = $tmp['Description'] = '';
- $tmp['Reserved'] = $tmp['Track'] = $tmp['Genre'] = 0;
- }
- // basic items
- $items = array('Title', 'Artist', 'Copyright', 'Description', 'Year', 'AlbumTitle');
- foreach ($items as $k)
- {
- if (isset($pa[$k])) $tmp[$k] = $pa[$k];
- }
- // genre index
- if (isset($pa['Genre']))
- {
- $g = 0;
- foreach ($this->genres as $gtmp)
- {
- if (!strcasecmp($gtmp, $pa['Genre']))
- break;
- $g++;
- }
- $tmp['Genre'] = $g;
- }
- if (isset($pa['Track'])) $tmp['Track'] = intval($pa['Track']);
- // pack the data
- $buf = pack('a3a30a30a30a4a28CCC', $tmp['id'], $tmp['Title'], $tmp['Artist'], $tmp['AlbumTitle'],
- $tmp['Year'], $tmp['Description'], 0, $tmp['Track'], $tmp['Genre']);
- flock($this->fd, LOCK_EX);
- fseek($this->fd, $off, SEEK_END);
- fwrite($this->fd, $buf, 128);
- flock($this->fd, LOCK_UN);
- }
- // set v2 info
- function _set_v2_info($pa)
- {
- if (!$this->head)
- { // insert ID3
- return; // 没有就算了
- /**
- $tmp = array('id'=>'ID3','ver'=>3,'rev'=>0,'flag'=>0);
- $tmp['size'] = -10; // +10 => 0
- $this->head = $tmp;
- $this->head_buf = '';
- $this->head_off = 0;
- **/
- }
- $items = array( 'TCOP'=>'Copyright', 'TPE1'=>'Artist', 'TIT2'=>'Title', 'TRAC'=>'Track',
- 'TCON'=>'Genre', 'COMM'=>'Description', 'TYER'=>'Year', 'TALB'=>'AlbumTitle');
- $head_body = '';
- while (true)
- {
- $buf = $this->_read_head_buf(10);
- if (strlen($buf) != 10) break;
- $tmp = unpack('a4fid/Nsize/nflag', $buf);
- if ($tmp['size'] == 0) break;
- $data = $this->_read_head_buf($tmp['size']);
- if (($k = $items[$tmp['fid']]) && isset($pa[$k]))
- {
- // the data should prefix by "\0" [replace]
- $data = "\0" . $pa[$k];
- unset($pa[$k]);
- }
- $head_body .= pack('a4Nn', $tmp['fid'], strlen($data), $tmp['flag']) . $data;
- }
- // reverse the items & set the new tags
- $items = array_flip($items);
- foreach ($pa as $k => $v)
- {
- if ($fid = $items[$k])
- {
- $head_body .= pack('a4Nn', $fid, strlen($v) + 1, 0) . "\0" . $v;
- }
- }
- // new length
- $new_len = strlen($head_body) + 10;
- $old_len = $this->head['size'] + 10;
- if ($new_len < $old_len)
- {
- $head_body .= str_repeat("\0", $old_len - $new_len);
- $new_len = $old_len;
- }
- // count the size1,2,3,4, no include the header
- // 较为变态的算法... :p (28bytes integer)
- $size = array();
- $nlen = $new_len - 10;
- for ($i = 4; $i > 0; $i--)
- {
- $size[$i] = ($nlen & 0x7f);
- $nlen >>= 7;
- }
- $tmp = $this->head;
- //echo "old_len : $old_len new_len: $new_len\n";
- $head_buf = pack('a3CCCCCCC', $tmp['id'], $tmp['ver'], $tmp['rev'], $tmp['flag'],
- $size[1], $size[2], $size[3], $size[4]);
- $head_buf .= $head_body;
- $this->_file_save($head_buf, $old_len, $new_len);
- }
Tags: PHP获取音频文件
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