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• Revision 09830aa0ea : Small tweaks on the constant quality mode Improves results a little. derf is no

  10 septembre 2013, par Deb Mukherjee

  Changed Paths :
   Modify /vp9/encoder/vp9_onyx_if.c

  
  
  Small tweaks on the constant quality mode

  Improves results a little.
  derf is now +1.078% over bitrate control.

  Change-Id : I4812136f3e67be21d14ec089419976a32a841785

• How to sync between recording and input live video stream ?

  6 octobre 2012, par Abhishek Bansal

  I am working on a project in which I am receiving raw frames from some input video devices. I am trying to write those frames in a video files using FFMPEG library.
  I have no control over the frame rate i am getting from my input sources. This frame rate varies in run-time also.
  Now my problem is how do i sync between recorded video and coming video. Depending upon frame-rate i set in FFMPEG and actual frame rate that i am receiving playback of recorded video is either fast or slow than input video.
  I tried to add timestamps (as numOfFrames) in encoded video as per following link
  but that didn't help.

  ffmpeg speed encoding problem

  Please tell me a way to synchronize both. This is my first time with FFMPEG or any multimedia libraries so any examples will be highly appreciated.

  I am using directshow ISampleGrabber interface to capture those frames.
  Thank You

• run ffmpeg from PHP web script

  18 février 2014, par it6

  I need to manage the recording/capture of a website mindwhile it is running a slide-show to get videos form these slides.

  My approach is :

  <?php 
  
  
  
  define('FFMPEG_LIBRARY', '/usr/bin/ffmpeg ');
  
  
  
  $ffmpegcmd = "ffmpeg -f x11grab -r 25 -s 800x600 -i :0.0 /tmp/output.mpg";
  
  
  
  shell_exec($ffmpegcmd);  
  
  
  
  ?>

  But i get this error from php error log :

  [x11grab @ 0x81e8aa0] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 800 height: 600
  
  No protocol specified
  
  No protocol specified
  
  [x11grab @ 0x81e8aa0] Could not open X display.
  
  :0.0: Input/output error

  Similar command from console run good.

  Please, any help to get display and be able to control ffmpeg from browser php script ?

  Thanks in advance.

  ---

  thanks for your time.

  I got rid the X display error, but not I still haven't got the capture.

  Using xvfb I get an unknown file at /tmp written by www-data user :
   rw-r—r— 1 www-data www-data 11252 Sep 12 09:49 server-B20D7FC79C7F597315E3E501AEF10E0D866E8E92.xkm

  Running startx I got also an unknown file at /tmp
   rw------- 1 www-data www-data 59 Sep 12 09:53 serverauth.oLcFlG7tXC

  any of both grow in size so it is not capturing anything. The content is some binary thing.
  What are those files about ?

  What I am trying is to write a script in which I can control the time ffmpeg is capturing the desktop to create a video from a jquery slide displayed on a website.

  My try from console is closer, but if I can do it by browser I will be able to know when to stop sending an AJAX request once the slide is finished.

  This is my try from console :

  #!/bin/bash
  
  
  
  # start the slide website: I will need to change it to control by querystring the language and course level
  
  firefox http://www.languagecourse.net/vocabulary-trainer.php &
  
  # start recording: I will need to adjust the frame to capture
  
  ffmpeg -f x11grab -r 25 -s 800x600 -i :0.0 /tmp/output2.mpg &
  
  # since I can't control the time a course takes I pause an arbitrary time
  
  sleep 5
  
  # look for the capture PID and close it
  
  for i in $(ps aux | grep ffmpeg | sed "s/  */#/g" | cut -f2 -d#)
  
  do
  
    echo "proceso $i killed"
  
    kill -9 $i
  
  done

  I wonder once the website is opened I can continue doing the control from AJAX, but not know if I will be able to get the ffmpeg PID to stop the command.

  I will appreciate any kind of comments.

  Regards,
  ·_-