FFmpeg operation guide in PHP

FFmpeg is a command line-based audio and video processing tool that can be used for transcoding, editing, cropping, merging, acceleration, volume adjustment and other functions. It is widely used in the multimedia field. In PHP, we can also implement audio and video processing functions by calling FFmpeg's command line parameters. This article will introduce how to use FFmpeg to operate audio and video in PHP.

1. Install FFmpeg extension
To use FFmpeg in PHP, you need to install the FFmpeg extension first. You can enter the following command in the terminal to install:

sudo apt-get install ffmpeg
sudo apt-get install php-ffmpeg

After the installation is completed, you need to modify the php.ini file and remove the comment symbols from ffmpeg.so under extensions.

sudo nano /etc/php/7.2/apache2/php.ini

Find the following code segment:

;extension=bcmath.so
;extension=bz2.so
;extension=ctype.so
;extension=calendar.so
;extension=dba.so
;extension=exif.so
;extension=ftp.so
;extension=gettext.so
;extension=iconv.so
;extension=json.so
;extension=mysqli.so
;extension=pdo_mysql.so
;extension=shmop.so
;extension=sockets.so
;extension=sqlite3.so
;extension=sysvmsg.so
;extension=sysvsem.so
;extension=sysvshm.so
;extension=xmlrpc.so

Remove the comment symbol ";" in extension=ffmpeg.so.

After the installation is completed, you can use the following code to test whether the installation is successful:

<?php
  if(extension_loaded('ffmpeg')) {
    echo 'FFmpeg扩展已安装';
  } else {
    echo '请确认是否安装FFmpeg扩展';
  }
?>

2. Use FFmpeg
The basic function of FFmpeg is to convert audio and video files in different formats into different formats Audio and video files, here are some simple usage examples:

1. Convert mp4 to avi format
   Enter the following command on the command line:

ffmpeg -i input.mp4 output.avi

In PHP The command line parameters can be executed through the exec() function:

<?php
  exec('ffmpeg -i input.mp4 output.avi');
?>

2. Crop video
   The following command can crop the first 5 seconds of the original video:

ffmpeg -ss 00:00:00 -t 00:00:05 -i input.mp4 output.mp4

In PHP:

<?php
  exec('ffmpeg -ss 00:00:00 -t 00:00:05 -i input.mp4 output.mp4');
?>

3. Splicing video
   The following command can merge two video files into one:

ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex "concat=n=2:v=1:a=1" output.mp4

In PHP:

<!--?php
  exec('ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex "concat=n=2:v=1:a=1" output.mp4');
?-->

4. Adjust video size
   The following command can adjust the video size to 1366*768:

ffmpeg -i input.mp4 -vf scale=1366:768 output.mp4

In PHP:

<?php
  exec('ffmpeg -i input.mp4 -vf scale=1366:768 output.mp4');
?>

5. Adjust volume
   The following command can reduce the volume by half:

ffmpeg -i input.mp4 -af "volume=0.5" output.mp4

In PHP:

<!--?php
  exec('ffmpeg -i input.mp4 -af "volume=0.5" output.mp4');
?-->

FFmpeg has more advanced functions, which can be learned through the official documentation: https: //www.ffmpeg.org/documentation.html

3. Avoid security risks
Since the exec() function executes command line parameters, it may cause security risks, such as injection attacks. In order to avoid this risk, the following methods can be used:

1. Strictly filter and check user input to ensure that the entered parameters do not contain malicious code.
2. Use the escapeshellarg() function to escape parameters to prevent special characters from being mistaken for command line codes.
3. Use safe_mode to prohibit the exec function from executing external commands.

In short, you need to carefully consider security issues when using FFmpeg to avoid risks to your website and server.

IV. Summary
This article introduces the basic operations of using FFmpeg in PHP, including installing FFmpeg extensions, using FFmpeg to achieve audio and video conversion, cropping, splicing, resizing, adjusting volume and other functions, and provides Recommendations for avoiding security risks. I hope this article can help readers who want to use FFmpeg in PHP.

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