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• avcodec/pngenc : fix sBIT writing for indexed-color PNGs

  19 juillet 2024, par Leo Izen

  avcodec/pngenc : fix sBIT writing for indexed-color PNGs
  We currently write invalid sBIT entries for indexed PNGs, which by PNG
  
  specification[1] must be 3-bytes long. The values also are capped at 8
  
  for indexed-color PNGs, not the palette depth. This patch fixes both of
  
  these issues previously fixed in the decoder, but not the encoder.
  [1] : https://www.w3.org/TR/png-3/#11sBIT
  Regression since : c125860892e931d9b10f88ace73c91484815c3a8.
  Signed-off-by : Leo Izen <leo.izen@gmail.com>
  
  Reported-by : Ramiro Polla : <ramiro.polla@gmail.com>
  

  • [DH] libavcodec/pngenc.c

• FFmpeg gradient with color codes

  31 août 2018, par Praveen Tamil

  How to generate linear gradient image with following color codes ?

  #485c6e, #b9b9b0,#4b6974
  I’ve generated the gradient in css with linear-gradient(#485c6e,#b9b9b0 15%,#4b6974);

  Expected output :
  

• ffmpeg images to video with different start times and durations

  25 mai 2018, par Rich

  I’ve recently learned of FFMPEG’s existence and I am trying to use it on my wordpress site.

  On the site I am working on a html/php/js form page that lets users upload pictures, and set when the image shows and for how long.

  Right now the code I have is only showing one image for the entire video.

  <?php if (isset($_POST['button'])) { 
  
  echo shell_exec('ffmpeg -t '.$cap_1.' -i /myurl/beach-1866431.jpg -t '.$cap_2.' -i /myurl/orlando-1104481-1.jpg -filter_complex "scale=1280:-2" -i /myurl/audio.mp3 -c:v libx264 -pix_fmt yuv420p -t 30 -y /myurl/'.$v_title.'.mp4 2>&1');
  
   } ?>

  I tried setting "-t" for the duration with my php variables but nothing changes and I cant figure out what to use for the start time of each image.

  Also, when writing shell_exec commands, instead of it all being on one line, is there a way to write working command code in php files with line breaks ? For example -

   <?php if (isset($_POST['button'])) { 
  
      echo shell_exec('ffmpeg -t '.$cap_1.' -i /myurl/beach-1866431.jpg 
  
      -t '.$cap_2.' -i /myurl/orlando-1104481-1.jpg 
  
      -filter_complex "scale=1280:-2" 
  
      -i /myurl/audio.mp3 
  
      -c:v libx264 -pix_fmt yuv420p -t 30 -y /myurl/'.$v_title.'.mp4 2>&1');
  
           } ?>

  EDIT

  So far the concat text file seems to work, however I do not know how to set the start times for each image ---

  ffconcat version 1.0
  
  file /path/beach-1866431.jpg
  
  duration 3
  
  file /path/orlando-1104481-1.jpg
  
  duration 5
  
  file /path/beach-1866431.jpg

  And ffmpeg command -

  shell_exec('ffmpeg -f concat -safe 0 -i /path/file.txt -filter_complex "scale=1280:-2" -i /path/audio.mp3 -c:v libx264 -pix_fmt yuv420p -t 30 -y /path/'.$v_title.'.mp4 2>&1');

  EDIT 2

  Using the concat method suggested, my code now looks like this —

  <?php if (isset($_POST['button'])) { 
  
  echo shell_exec('ffmpeg \
  
  -loop 1 -framerate 24 -t 10 -i goldmetal.jpg \
  
  -i 3251.mp3 \
  
  -loop 1 -framerate 24 -t 10 -i cash-register-1885558.jpg \
  
  -loop 1 -framerate 24 -t 10 -i ice-1915849.jpg \
  
  -filter_complex "[0:v][1:a][2:v][3:v]concat=n=4:v=1:a=1[v][a]" -map "[v]" -map "[a]" -c:v libx264 /path/'.$v_title.'.mp4 2>&1');
  
   } ?>

  But I’m getting this error —

  **Stream specifier ':v' in filtergraph description [0:v][1:a][2:v][3:v]concat=n=4:v=1:a=1[v][a] matches no streams.**

  EDIT 3

  I almost got it working as needed, using 2 commands, one for the images and fade, the other to combine the audio. The only issue I’m having is changing the time each image shows up. —

  echo shell_exec('ffmpeg \
  
  -loop 1 -t 5 -i '.$thepath .'/'.$v_pix1.' \
  
  -loop 1 -t 5 -i ' .$thepath . '/cash-register-1885558.jpg \
  
  -loop 1 -t 5 -i ' .$thepath . '/ice-1915849.jpg \
  
  -loop 1 -t 5 -i '.$thepath .'/'.$v_pix1.' \
  
  -loop 1 -t 5 -i ' .$thepath . '/ice-1915849.jpg \
  
  -filter_complex \
  
  "[0:v]setpts=PTS-STARTPTS,fade=t=out:st=4:d=1,scale=1280:720,setdar=16/9,setsar=sar=300/300[v0]; \
  
   [1:v]setpts=PTS-STARTPTS,fade=t=in:st=0:d=1,fade=t=out:st=4:d=1,scale=1280:720,setdar=16/9,setsar=sar=300/300[v1]; \
  
   [2:v]setpts=PTS-STARTPTS,fade=t=in:st=0:d=1,fade=t=out:st=4:d=1,scale=1280:720,setdar=16/9,setsar=sar=300/300[v2]; \
  
   [3:v]setpts=PTS-STARTPTS,fade=t=in:st=0:d=1,fade=t=out:st=4:d=1,scale=1280:720,setdar=16/9,setsar=sar=300/300[v3]; \
  
   [4:v]setpts=PTS-STARTPTS,fade=t=in:st=0:d=1,fade=t=out:st=4:d=1,scale=1280:720,setdar=16/9,setsar=sar=300/300[v4]; \
  
   [v0][v1][v2][v3][v4]concat=n=5:v=1:a=0,format=yuv420p[v]" -map "[v]" -y '.$thepath .'/fadeout.mp4 2>&1');
  
  
  
  
  
  echo shell_exec('ffmpeg \
  
  -i '.$thepath .'/fadeout.mp4 \
  
  -i '.$thepath .'/3251.mp3 \
  
  -filter_complex "[0:v:0][1:a:0] concat=n=1:v=1:a=1 [vout] [aout]" -map "[vout]" -map "[aout]" -c:v libx264 -r 1 -y '.$thepath .'/mergetest.mp4 2>&1');