Recherche avancée

Sur d’autres sites (2940)

• converting video with php and ffmpeg

  6 mai 2015, par Ford

  i am trying a simple test to learn how to convert videos with ffmpeg via PHP as they are uploaded to my site (to .mp4).
  however am i missing something, as my simple test is doing nothing....

  code (simplified)

  $videoFile = '/home/xxx/public_html/dev/videos/1746/sample.avi';
  
  exec("ffmpeg -i $videoFile -vcodec h264 -acodec aac -strict -2 /home/xxx/public_html/dev/videos/1746/test.mp4");

  i have also trired

  system("ffmpeg -i $videoFile -vcodec h264 -acodec aac -strict -2 /home/xxx/public_html/dev/videos/1746/test.mp4");

  and

  shell_exec("ffmpeg -i $videoFile -vcodec h264 -acodec aac -strict -2 /home/xxx/public_html/dev/videos/1746/test.mp4");

  Also if i try

  echo exec('ffmpeg -formats');

  i get no output

  none of the above convertion tests work and no test.mp4 file is created.
  i have error reporting turned on yet get no errors.

  any advice would be welcomed please

• ffmpeg - can't concat because of corrupted video file

  22 avril 2022, par neko

  I'm trying to concat 5 video files taken by my gopro. The problem is that the 5th file is a little corrupted because the gopro ran out of battery and I guess some stuff didn't get saved correctly.

  


  I can still play this 5th file in any player, upload it on YouTube, use it in Vegas pro, it just has some visual glitches every few and then.

  


  When trying to concat the 5 files in ffmpeg, everything is fine for the 4 first files but when the 5th get processed I get a ton of "Non-monotonous DTS in output stream 0:0 This may result in incorrect timestamps in the output file." errors, and the output video just doesn't include the data from my 5th video.

  


  I've tried everything to make this 5th video usable. Re-encode it to different formats, Re-render it using Vegas pro, uploaded it to different video streaming websites and downloading their proccessed version, I even got as far as to record it playing from vlc using obs, but EVERY time the video obtained couldn't be concated with the 4 first. I was still getting the DTS error and the output didn't include the footage.

  


  What can I do ? I don't even understand how footage recorded through obs could get the same corrupted data as the source file.

  


• Enhance text image in x264 encoding

  24 août 2016, par useprxf

  I’m making use of x264 for remote desktop streaming. The goal is to achieve both low bitrate and high video quality within the computation budget. The current parameter set I used almost achieve this goal, but it fails in handling images with many texts (e.g. browsing websites scene). The text in image is blurred and affects the user experience.

  I think it’s the quantization in x264 that causes this. The quantization after DCT transform will eliminate high frequency sinals which mainly correspond to texts in image.

  So, my question is how to improve the text quality in x264 encoding ?

  My idea : when the bitrate stays at a low level for a period of time,

  1. set crf to be 0 (lossless) ;
  2. encode current frame as an IDR frame and then send it ;
  3. recover the crf.

  Also, a flag should be used to prevent resending when bitrate keeps low for a long time. I haven’t try this method since I don’t know how to mark a frame as an IDR frame manully and then encode it.