Recherche avancée

Sur d’autres sites (9468)

• avcodec : Assert on codec->encode2 in encode_audio2

  27 août 2015, par lummax

  avcodec : Assert on codec->encode2 in encode_audio2
  Assert on `avctx->codec->encode2` to avoid a SEGFAULT on the subsequent
  
  function call.
  avcodec_encode_video2() uses a similar assertion.
  
  Calling the wrong function on a stream is a serious inconsistency
  
  which could at other places be potentially dangerous and exploitable,
  
  it is thus safer to stop execution and not continue with such
  
  inconsistency after returning an error.
  Commit-message-extended-by commiter
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/utils.c

• Sub-pixel rendering with imagettftext()

  8 mars 2016, par user1661677

  I’m creating an image sequence, and encoding it to a video using PHP, GD library and ffmpeg. You’ll see I’m animating the two text layers inversely of each other, on the X axis. And with some simple operators $i/2 and $i/3, I’m trying to make their movement slower in the final animation.

  The problem I’m having is that when the video is rendered out, each layer’s text is only moving ever second, and third frame, respectively. This causes the animation to be a bit ’jerky’ and just not as smooth as Adobe After Effects with it’s ability to support sub-pixel rendering of elements.

  Is there any way to get imagettftext(), or some other method of drawing on images to support sub-pixel rendering ?

  Thank you.

  for ($i = 1; $i <= 125; $i++) {
  
  
  
      // Text on Image
  
      $front = imagecreatefromjpeg('front.jpg');
  
      $white = imagecolorallocate($front, 255, 255, 255);
  
      $text = 'some text';
  
      $text2 = 'some other text';
  
      $font = '/var/www/html/test/OpenSans-Bold.ttf';
  
  
  
      // Add text
  
      imagettftext($front, 60, 0, 1340-($i/2), 720, $white, $font, $text);
  
      imagettftext($front, 35, 0, 1240+($i/3), 800, $white, $font, $text2);
  
  
  
      // Write image to file
  
      imagejpeg($front, "images/".$i.".jpg", 100);
  
  }

• I can not apply an overlay on top of an overlay using ffmpeg

  25 septembre 2019, par meraklis56

  As the title says, I can not apply an overlay on top of an overlay. More specifically, I have these layers :

  1. background
  2. video
  3. stickers

  And I want to create a fourth layer, on the size of 1 and 3rd layer. So the order I want to have is :

  1. white layer
  2. background
  3. video
  4. stickers

  Following the documentation I came up with :

  const command = [
  
             '-y', // always overwrite file
  
             '-loop', '1', // one time
  
             '-i', dataObject['bg_src'], // bg image
  
             '-i', dataObject['videos']['main']['src'], // video
  
             '-i', dataObject['fg_src'], // sticker image
  
             '-i', dataObject['fg_src'], // bg image2
  
             '-preset', 'veryfast', // fast encoding
  
             '-crf', '23', // quality
  
             '-vcodec','libx264', // codec
  
             '-t', '3', // time threshold
  
             '-loglevel', '24', // verbose level
  
             '-filter_complex',
  
             '[0:v]pad=ceil(iw/2)*2:ceil(ih/2)*2[bg_src];' +                      // bg_src: to make width even, export it as [bg_src]
  
             '[2:v]pad=ceil(iw/2)*2:ceil(ih/2)*2[fg_src];' +                      // fg_src: to make width even, export it as [fg_src]
  
             '[3:v]pad=ceil(iw/2)*2:ceil(ih/2)*2[fg_src2];' +                     // bg_src: to make width even, export it as [fg_src2]
  
             'color=white,format=rgb24[white_canvas];' +                          // create white background
  
             '[white_canvas][fg_src2]scale2ref[b][a];' +                          // make white background same size as [fg_src2]
  
             '[a][b]overlay=0:0[white_canvas_scaled];' +                          // export it as white_canvas_scaled
  
             '[1:v]scale=%s:-1[video_scaled];' +                                  // video: scale it (width is injected here)
  
             '[white_canvas_scaled][video_scaled]overlay=%s:%s:shortest=1[bg];' + // white background & scaled video
  
             '[bg][bg_src]overlay=0:0[bg2]',                                      // bg_src overlay here
  
             '[bg2][fg_src]overlay=0:0',                                          // fg_src overlay here
  
             FileService.photoPath + '/output.mp4'];

  But in last command fails and I receive :

  Unable to find a suitable output format for ’[bg2][fg_src]overlay=0:0’

  What is wrong ?