PHP实现将视频转成MP4并获取视频预览图的方法

<?php
flv_convert_get_thumb('input.avi', 'output.jpg', 'output.ogm');
// code provided and updated by steve of phpsnaps ! thanks
// accepts:
// 1: the input video file
// 2: path to thumb jpg
// 3: path to transcoded mpeg?
function flv_convert_get_thumb($in, $out_thumb, $out_vid)
{
  // get thumbnail
  $cmd = 'ffmpeg -v 0 -y -i '.$in.' -vframes 1 -ss 5 -vcodec mjpeg -f rawvideo -s 286x160 -aspect 16:9 '.$out_thumb;
  $res = shell_exec($cmd);
  // $res is the output of the command
  // transcode video
  $cmd = 'mencoder '.$in.' -o '.$out_vid.' -af volume=10 -aspect 16:9 -of avi -noodml -ovc x264 -x264encopts bitrate=500:level_idc=41:bframes=3:frameref=2: nopsnr: nossim: pass=1: threads=auto -oac mp3lame';
  $res = shell_exec($cmd);
}
?>