Newest 'ffmpeg' Questions - Stack Overflow

Les articles publiés sur le site

• Securely using the PHP exec function

  19 janvier 2012, par siberiantiger

  I am writing a PHP script designed to run an executable file (ffmpeg.exe) via the exec() function. The problem is that I have read that using the exec() function can be a security risk and should be avoided if possible. I have been doing some research into how to run the exec() function securely, and the only thing that I keep coming across is to filter the command string with escapeshellcmd or escapeshellarg. What I want to know is if it is possible to further increase security when using the exec() function or if there is a secure alternative to exec(). Any help would be appreciated.

  Here is my code;

  define('FFMPEG_LIBRARY', 'c:\\ffmpeg7\\ffmpeg\\bin\\ffmpeg ');
  $transcode_string = FFMPEG_LIBRARY." -i " . $srcFile . " -acodec libmp3lame -ab 64k -ar 22050 -ac 1 -vcodec libx264 -b:v 250k -r 30 -f flv -y " . $destFile;
  $transcode_string = escapeshellcmd($transcode_string);
  exec($transcode_string);
  

  $srcFile is basically the video for transcoding while $destFile is the output file I wish to create.

• how to explicitly specify matroska format file to be VFR

  19 janvier 2012, par Ulterior

  I am moving my code performing AVI recording with ffmpeg library to matroska format due to native support of VFR stated by format. Changing guess_format to matroska not touching any other settings produced an mkv file which seems to be ok. But the MediaInfo reports it to be CFS (30).

  How do I explicitly state that its VFR?

  Format                           : Matroska
  File size                        : 5.27 MiB
  Duration                         : 8s 0ms
  Overall bit rate                 : 5 528 Kbps
  Writing application              : Lavf52.78.1
  Writing library                  : Lavf52.78.1
  
  Video
  ID                               : 1
  Format                           : MPEG-4 Visual
  Format profile                   : Simple@L1
  Format settings, BVOP            : Yes
  Format settings, QPel            : No
  Format settings, GMC             : No warppoints
  Format settings, Matrix          : Default (H.263)
  Codec ID                         : V_MPEG4/ISO/ASP
  Codec ID/Info                    : Advanced Simple Profile
  Duration                         : 8s 0ms
  Width                            : 1 280 pixels
  Height                           : 720 pixels
  Display aspect ratio             : 16:9
  Frame rate                       : 30.000 fps
  Color space                      : YUV
  Bit depth                        : 8 bits
  Scan type                        : Progressive
  Writing library                  : Intel(R) MPEG-4 encoder based on Intel(R) IPP 6.1 build 137.36[6.1.137.779]
  Language                         : English
  
  Audio
  ID                               : 2
  Format                           : MPEG Audio
  Codec ID                         : A_MPEG/L3
  Codec ID/Hint                    : MP3
  Duration                         : 8s 0ms
  Channel(s)                       : 2 channels
  Sampling rate                    : 44.1 KHz
  Language                         : English
  

• Grabbing rtsp/rtp stream with libavformat

  19 janvier 2012, par T0ha

  world. I'm trying to grab rtsp mjpeg stream from IP-camera (realtime) as described in http://www.inb.uni-luebeck.de/~boehme/using_libavcodec.html, but ported to newer version. It works well with mpeg file (loading it full as one AVPacket), but working with stream, avcodec_decode_video2 returns -1 (error). AVPacket in this case is a part of a frame.

  How can I fix this?

• How to map an audio clip to a video ?

  19 janvier 2012, par simpatico

  I have a video clip, and an audio clip extracted from it. How can I trim the the video clip to to the portion extracted in the audio clip?

  I imagine the solution will consist of:

  1. Automatically identify the pair of start position of the audio clip in the video clip, and the end position (e.g. <03:05,09:55>);
  2. Trim the video from the identified start to the identified end (that's easy).

• Video to FLV code in php

  18 janvier 2012, par freelanceinphp

  I am looking for efficient and easy to implement code which work for media file to flv conversion.

  Please give me some referral sites or links.