PHP做视频网站，让程序自动实现视频格式转换、设置视频大小、生成视频缩略图...

一、PHP实现转换

　　　在做视频网站的时候，最头痛的问题可能是格式转换、视频缩略图等。下面我将用PHP实现这一些功能。PHP是没有自带视频的函数，所以会用到第三方的软件工具来实现。

 

二、什么是FFmpeg

　　　FFmpeg是一个开源免费跨平台的视频和音频流方案，属于自由软件，采用LGPL或GPL许可证（依据你选择的组件）。它提供了录制、转换以及流化音视频的完整解决方案。它包含了非常先进的音频/视频编解码库libavcodec，为了保证高可移植性和编解码质量，libavcodec里很多codec都是从头开发的。

FFmpeg在Linux平台下开发，但它同样也可以在其它操作系统环境中编译运行，包括Windows、Mac OS X等。

这个项目最早由Fabrice Bellard发起，现在由Michael Niedermayer维护。许多FFmpeg的开发人员都来自MPlayer项目，而且当前FFmpeg也是放在MPlayer项目组的服务器上。项目的名称来自MPEG视频编码标准，前面的"FF“代表"Fast Forward“。 更多详情》

/* 转视频   */
$cmd="ffmpeg.exe -i tiwer_update_move.avi -ab 56 -ar 22050 -b 500 -r 15 -s 500x600 201112120089123.flv";  exec($cmd);  /*  视频截图*/
$cmd="ffmpeg.exe -itiwer_update_move.avi -f image2 -ss 10 -s 600*500 -vframes 1 201112120089123.jpg";   

exec($cmd);  

 三、生成缩略图

 

 include("ImageHelper.class.php");/* 生成缩略图 */$thumbnail = new ImageHelper();  $thumbnail->resizeimage("2012121208123.jpg", 30,30, 0, "2012121208123_small.jpg");  

 

　　

四、工具类与软件下载

　　４.１ 图片处理工具类如下

/**
 * 图片处理工具
 *
 * Project: BoBo Manage System
 * This is NOT a freeware, use is subject to license terms!
 * 
 * Site: http://www.bobo123.cn
 *
 * $Id: ImageHelper.class.php 269 2011-03-08 00:44:01Z wgw8299 $
 *
 * Copyright © 2007-2012 Bobo123.CN Developer Team. All Rights Reserved.
 */
class ImageHelper {  


    var $type;  
     
     
    /* 实际宽度 */ 
    var $width;  
     
    /* 实际高度  */ 
    var $height;  
     
    /* 改变后的宽度   */
    var $resize_width;  
     
    /* 改变后的高度 */  
    var $resize_height;  
     
    /* 是否裁图   */
    var $cut;  
     
    /* 源图象  */ 
    var $srcimg;  
     
    /* 目标图象地址  */ 
    var $dstimg;  
     
    /* 临时创建的图象  */ 
    var $im;  
  
    function resizeimage($img, $wid, $hei,$c,$dstpath) {  
       
        $this->srcimg = $img;  
        $this->resize_width = $wid;  
        $this->resize_height = $hei;  
        $this->cut = $c;  
         
        /* 图片的类型  */ 
        $this->type = strtolower(substr(strrchr($this->srcimg,"."),1));  
         
        /* 初始化图象  */ 
        $this->initi_img();  
         
        /* 目标图象地址   */
        $this -> dst_img($dstpath);  
         
         
        $this->width = imagesx($this->im);  
        $this->height = imagesy($this->im);  
         
        /* 生成图象  */
        $this->newimg();  
         
        ImageDestroy ($this->im);  
    }  
  
    function newimg() {  
  
        /* 改变后的图象的比例  */ 
        $resize_ratio = ($this->resize_width)/($this->resize_height);  
  
        /* 实际图象的比例 */  
        $ratio = ($this->width)/($this->height);  
  
  
        if(($this->cut)=="1") {  
            /* 裁图高度优先 */  
            if($ratio>=$resize_ratio){  
                $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);  
                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this->resize_height, (($this->height)*$resize_ratio), $this->height);  
                ImageJpeg ($newimg,$this->dstimg);  
            }  
             
             
            /* 裁图 宽度优先  */ 
            if($ratio<$resize_ratio) {  
                $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);  
                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, (($this->width)/$resize_ratio));  
                ImageJpeg ($newimg,$this->dstimg);  
            }  
        } else {  
        
            /* 不裁图  */ 
            if($ratio>=$resize_ratio) {  
                $newimg = imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio);  
                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this->resize_width)/$ratio, $this->width, $this->height);  
                ImageJpeg ($newimg,$this->dstimg);  
            }  
            if($ratio<$resize_ratio) {  
                $newimg = imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height);  
                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, ($this->resize_height)*$ratio, $this->resize_height, $this->width, $this->height);  
                ImageJpeg ($newimg,$this->dstimg);  
            }  
        }  
    }  
  
    /* 初始化图象 */  
    function initi_img() {  
        if($this->type=="jpg") {  
            $this->im = imagecreatefromjpeg($this->srcimg);  
        }  
         
        if($this->type=="gif") {  
            $this->im = imagecreatefromgif($this->srcimg);  
        }  
         
        if($this->type=="png") {  
            $this->im = imagecreatefrompng($this->srcimg);  
        }  
         
        if($this->type=="bmp") {  
            $this->im = $this->imagecreatefrombmp($this->srcimg);  
        }  
    }  
  
  
    /* 图象目标地址   */
    function dst_img($dstpath) {  
        $full_length  = strlen($this->srcimg);  
        $type_length  = strlen($this->type);  
        $name_length  = $full_length-$type_length;  
        $name = substr($this->srcimg,0,$name_length-1);  
        $this->dstimg = $dstpath;  
    }  
    
    
     
    function ConvertBMP2GD($src, $dest = false) {  
        if(!($src_f = fopen($src, "rb"))) {  
            return false;  
        }  
        if(!($dest_f = fopen($dest, "wb"))) {  
            return false;  
        }  
        $header = unpack("vtype/Vsize/v2reserved/Voffset", fread($src_f,14));  
        $info = unpack("Vsize/Vwidth/Vheight/vplanes/vbits/Vcompression/Vimagesize/Vxres/Vyres/Vncolor/Vimportant", fread($src_f, 40));  
         
        extract($info);  
        extract($header);  
         
        if($type != 0x4D42) { // signature "BM"  
            return false;  
        }  
         
        $palette_size = $offset - 54;  
        $ncolor = $palette_size / 4;  
        $gd_header = "";  
        // true-color vs. palette  
        $gd_header .= ($palette_size == 0) ? "\xFF\xFE" : "\xFF\xFF";  
        $gd_header .= pack("n2", $width, $height);  
        $gd_header .= ($palette_size == 0) ? "\x01" : "\x00";  
        if($palette_size) {  
            $gd_header .= pack("n", $ncolor);  
        }  
        
        $gd_header .= "\xFF\xFF\xFF\xFF";  
  
        fwrite($dest_f, $gd_header);  
  
        if($palette_size) {  
            $palette = fread($src_f, $palette_size);  
            $gd_palette = "";  
            $j = 0;  
            while($j < $palette_size) {  
                $b = $palette{$j++};  
                $g = $palette{$j++};  
                $r = $palette{$j++};  
                $a = $palette{$j++};  
                $gd_palette .= "$r$g$b$a";  
            }  
            $gd_palette .= str_repeat("\x00\x00\x00\x00", 256 - $ncolor);  
            fwrite($dest_f, $gd_palette);  
        }  
  
        $scan_line_size = (($bits * $width) + 7) >> 3;  
        $scan_line_align = ($scan_line_size & 0x03) ? 4 - ($scan_line_size &  
        0x03) : 0;  
  
        for($i = 0, $l = $height - 1; $i < $height; $i++, $l--) {  
            // BMP stores scan lines starting from bottom  
            fseek($src_f, $offset + (($scan_line_size + $scan_line_align) * $l));  
            $scan_line = fread($src_f, $scan_line_size);  
            if($bits == 24) {  
                $gd_scan_line = "";  
                $j = 0;  
                while($j < $scan_line_size) {  
                    $b = $scan_line{$j++};  
                    $g = $scan_line{$j++};  
                    $r = $scan_line{$j++};  
                    $gd_scan_line .= "\x00$r$g$b";  
                }  
            }  
            else if($bits == 8) {  
                $gd_scan_line = $scan_line;  
            }  
            else if($bits == 4) {  
                $gd_scan_line = "";  
                $j = 0;  
                while($j < $scan_line_size) {  
                    $byte = ord($scan_line{$j++});  
                    $p1 = chr($byte >> 4);  
                    $p2 = chr($byte & 0x0F);  
                    $gd_scan_line .= "$p1$p2";  
                }  
                $gd_scan_line = substr($gd_scan_line, 0, $width);  
            }  
            else if($bits == 1) {  
                $gd_scan_line = "";  
                $j = 0;  
                while($j < $scan_line_size) {  
                    $byte = ord($scan_line{$j++});  
                    $p1 = chr((int) (($byte & 0x80) != 0));  
                    $p2 = chr((int) (($byte & 0x40) != 0));  
                    $p3 = chr((int) (($byte & 0x20) != 0));  
                    $p4 = chr((int) (($byte & 0x10) != 0));  
                    $p5 = chr((int) (($byte & 0x08) != 0));  
                    $p6 = chr((int) (($byte & 0x04) != 0));  
                    $p7 = chr((int) (($byte & 0x02) != 0));  
                    $p8 = chr((int) (($byte & 0x01) != 0));  
                    $gd_scan_line .= "$p1$p2$p3$p4$p5$p6$p7$p8";  
                }  
                $gd_scan_line = substr($gd_scan_line, 0, $width);  
            }  
            fwrite($dest_f, $gd_scan_line);  
        }  
        fclose($src_f);  
        fclose($dest_f);  
        return true;  
    }  
  
    function imagecreatefrombmp($filename) {  
        $tmp_name = tempnam("/tmp", "GD");  
        if($this->ConvertBMP2GD($filename, $tmp_name)) {  
            $img = imagecreatefromgd($tmp_name);  
            unlink($tmp_name);  
            return $img;  
        }  
        return false;  
    }  
     
     
} 

 　　4.2 软件下载

　　FFmpeg官方下载：http://ffmpeg.org/download.html