PHP基于ffmpeg实现转换视频，截图及生成缩略图的方法

include("ImageResize.class.php")
 //转视频
 $cmd="ffmpeg.exe -i starwar.avi -ab 56 -ar 22050 -b 500 -r 15 -s 320x240 1.flv";
 exec($cmd);
 //视频截图
 $cmd="ffmpeg.exe -i starwar.avi -f image2 -ss 10 -s 400*300 -vframes 1 1.jpg";
 exec($cmd);
 //生成缩略图
 $thumbnail = new ImageResize();
 $thumbnail->resizeimage("1.jpg", 30,30, 0, "small1.jpg");
class ImageResize {
  //图片类型
  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;
    //echo $this->dstimg;
  }
  function ConvertBMP2GD($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);
    }
    // no transparency
    $gd_header .= "\xFF\xFF\xFF\xFF";
fwrite($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;
  }
}