PHP中将图片转换为base64编码的方法

<?php
//短网址生成算法
class ShortUrl {
   
    //字符表
    public static $charset = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
    public static function encode($url)
    {
        $key = 'abc'; //加盐
        $urlhash = md5($key . $url);
        $len = strlen($urlhash);
 
        //将加密后的串分成4段，每段4字节，对每段进行计算，一共可以生成四组短连接
        for ($i = 0; $i < 4; $i++) {
            $urlhash_piece = substr($urlhash, $i * $len / 4, $len / 4);
           
            //将分段的位与0x3fffffff做位与，0x3fffffff表示二进制数的30个1，即30位以后的加密串都归零
            //此处需要用到hexdec()将16进制字符串转为10进制数值型，否则运算会不正常
            $hex = hexdec($urlhash_piece) & 0x3fffffff;
 
            //域名根据需求填写
            $short_url = "http://t.cn/";
           
            //生成6位短网址
            for ($j = 0; $j < 6; $j++) {
               
                //将得到的值与0x0000003d,3d为61，即charset的坐标最大值
                $short_url .= self::$charset[$hex & 0x0000003d];
               
                //循环完以后将hex右移5位
                $hex = $hex >> 5;
            }
 
            $short_url_list[] = $short_url;
        }
 
        return $short_url_list;
    }
}
 
$url = "http://www.111cn.net/";
$short = ShortUrl::encode($url);
print_r($short);
?>

<?php
define('FFMPEG_PATH', '/usr/local/ffmpeg2/bin/ffmpeg -i "%s" 2>&1');
 
function getVideoInfo($file) {
   
    $command = sprintf(FFMPEG_PATH, $file);
   
    ob_start();
    passthru($command);
    $info = ob_get_contents();
    ob_end_clean();
   
    $data = array();
    if (preg_match("/Duration: (.*?), start: (.*?), bitrate: (\d*) kb\/s/", $info, $match)) {
        $data['duration'] = $match[1]; //播放时间
        $arr_duration = explode(':', $match[1]);
        $data['seconds'] = $arr_duration[0] * 3600 + $arr_duration[1] * 60 + $arr_duration[2]; //转换播放时间为秒数
        $data['start'] = $match[2]; //开始时间
        $data['bitrate'] = $match[3]; //码率(kb)
    }
    if (preg_match("/Video: (.*?), (.*?), (.*?)[,\s]/", $info, $match)) {
        $data['vcodec'] = $match[1]; //视频编码格式
        $data['vformat'] = $match[2]; //视频格式
        $data['resolution'] = $match[3]; //视频分辨率
        $arr_resolution = explode('x', $match[3]);
        $data['width'] = $arr_resolution[0];
        $data['height'] = $arr_resolution[1];
    }
    if (preg_match("/Audio: (\w*), (\d*) Hz/", $info, $match)) {
        $data['acodec'] = $match[1]; //音频编码
        $data['asamplerate'] = $match[2]; //音频采样频率
    }
    if (isset($data['seconds']) && isset($data['start'])) {
        $data['play_time'] = $data['seconds'] + $data['start']; //实际播放时间
    }
    $data['size'] = filesize($file); //文件大小
    return $data;
}
 
//用法
$video_info = getVideoInfo('video.mp4');
print_r($video_info);
?>

//获得视频文件的缩略图
function getVideoCover($file,$time,$name) {
     if(empty($time))$time = '1';//默认截取第一秒第一帧
     $strlenstrlen = strlen($file);
     // $videoCover = substr($file,0,$strlen-4);
     // $videoCoverName = $videoCover.'.jpg';//缩略图命名
     //exec("ffmpeg -i ".$file." -y -f mjpeg -ss ".$time." -t 0.001 -s 320x240 ".$name."",$out,$status);
     $str = "ffmpeg -i ".$file." -y -f mjpeg -ss 3 -t ".$time." -s 320x240 ".$name;
     //echo $str."
";
     $result = system($str);
     }
 
//获得视频文件的总长度时间和创建时间
function getTime($file){
     $vtime = exec("ffmpeg -i ".$file." 2>&1 | grep 'Duration' | cut -d ' ' -f 4 | sed s/,//");//CuPlayer.com 总长度
     $ctime = date("Y-m-d H:i:s",filectime($file));//创建时间
     //$duration = explode(":",$time);
     // $duration_in_seconds = $duration[0]*3600 + $duration[1]*60+ round($duration[2]);//CuPlayer.com 转化为秒
     return array('vtime'=>$vtime,
     'ctime'=>$ctime
     );
}