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• Changing YUV values of AVFrames

  31 janvier 2012, par Kage

  I'm trying to apply an effect to a video by altering the YUV values using FFMpeg programmatically in C.

  Let's say I want to increase the luminescence of each pixel of each frame by 10.

  At the moment I can open a video, get the video stream, find a frame, decode the frame, alter the YUV values of the AvFrame->data, encode the frame, and save the frame to be played back.

  When I play back the video, the first frame looks as expected, but the next is even brighter and the one after that is even brighter, and each frame seems to be having more and more added to the Y values instead of just 10.

  I tried changing the code so instead of altering the pixels for each frame, it just alters the first AVFrame's data. However when I play the video back, it is not only the first frame that has been altered, but like the first 30 or so frames.

  Why are the other frames effected when I only change the AVFrame->data of the first frame ?

• ffmpeg quality with watermark

  17 juin 2012, par trialgod

  i want to add a watermark to a video with ffmpeg. At this time nearly all things are computing properly, except the quality of the new video is massively lower than in the one of the original video.

  I also use ffmpeg-php and tried to set the minrate to the Bitrate of the original, but then i get an Error. Code seems like this at the moment.

  $video     = new ffmpeg_movie('hot_wheels_for_adults.flv');
  
  $watermark = 'path/to/watermark.png';
  
  $width     = $video->getFrameWidth();
  
  $height    = $video->getFrameHeight();
  
  $exec = 'ffmpeg -i hot_wheels_for_adults.flv ' .
  
          '-y -vf "movie=' . $watermark . ' ' .
  
          '[watermark]; [in][watermark] overlay=main_w-overlay_w-10:main_h-overlay_h-10 [out]" ' .
  
          '-f flv -s ' . $width . 'x' . $height . ' ' .
  
          '-minrate ' . $video->getBitRate() . ' ' .
  
          'bla2.flv';

  Thats it. Without the '-minrate' line the quality isnt good.
  Originalrate = 630615,
  Rate of new Video = 328000.

  With the '-sameq' flag i got a good quality, but it is raised from 6,5MB to nearly 30MB...

  What can i do now ?

• Merge filename.mp4.tmp with filename.mp4

  10 janvier 2017, par Sathish

  How to merge a abc.mp4.tmp swap file with actual abc.mp4 file. I was trying to recording a live event using Wowza Media server 3.6 and the recorded file was not muxed properly at final moment. The abc.mp4.tmp swap file was not merged with actual abc.mp4 file. So could someone tell me how to merge the abc.mp4.tmp and abc.mp4 file and creates a new file and I can able to play with vlc

  Here is the mediainfo of the files

  [root@ip-ss-21-98-2 content]# mediainfo 03_03_2014_12_03_08.mp4
  
  General
  
  Complete name                            : 03_03_2014_12_03_08.mp4
  
  Format                                   : MPEG-4
  
  Format profile                           : Adobe Flash
  
  Codec ID                                 : f4v 
  
  File size                                : 5.20 GiB
  
  
  
  
  
  [root@ip-ss-21-98-2 content]# mediainfo 03_03_2014_12_03_08.mp4.tmp
  
  General
  
  Complete name                            : 03_03_2014_12_03_08.mp4.tmp
  
  File size                                : 38.3 MiB