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• why transparent drawbox does not work on some video sources?

  28 May 2019, by Wang

  It works on smptebars, smptehdbars, testsrc and testsrc2 but not other sources.

  ffplay -loglevel trace -f lavfi -i testsrc=r=1:d=1:size=800x600 -vf "drawbox=x=0:y=0:w='iw/2':h='ih/2':t=max:c=white@0.5"

  When I try this I can see the transparent box. But if I use color, and rgbtestsrc sources it does not work.

  ffplay -loglevel trace -f lavfi -i rgbtestsrc=r=1:d=1:size=800x600 -vf "drawbox=x=0:y=0:w='iw/2':h='ih/2':t=max:c=white@0.5"
  
  ffplay -loglevel trace -f lavfi -i color=c=red:r=1:d=1:size=800x600 -vf "drawbox=x=0:y=0:w='iw/2':h='ih/2':t=max:c=white@0.5"

  after looking at the trace output, it seems the transparency only works on rgb24 and yuv formats (yuv444p, yuv420p, etc.), this is surprising since we normally assume the rgba source can work with alpha channel.

  The following command change the pix_fmt to rgb24, then it works:

  ffplay -loglevel trace -f lavfi -i rgbtestsrc=r=1:d=1:size=800x600 -vf "format=pix_fmts=rgb24,drawbox=x=0:y=0:w='iw/2':h='ih/2':t=max:c=white@0.5"

  The following command change the pix_fmt to rgba, then it does not work:

  ffplay -loglevel trace -f lavfi -i rgbtestsrc=r=1:d=1:size=800x600 -vf "format=pix_fmts=rgba,drawbox=x=0:y=0:w='iw/2':h='ih/2':t=max:c=white@0.5"

  Why is that? and how can I fix this?

• Can't get FFMpeg to work with php

  15 October 2017, by casusbelli

  I’ve installed FFMpeg using composer on my Ubuntu LAMP 16.04 however I fail to make it work.

  I’m trying this simple code which make an instance of FFMpeg :

  $ffmpeg = FFMpeg\FFMpeg::create();
  
  $video = $ffmpeg->open('video101.MOV');

  However I get this error :

  Fatal error: Uncaught Error: Class 'FFMpeg\FFMpeg' not found in /var/www/html/upload/test.php:10 Stack trace: #0 {main} thrown in /var/www/html/upload/test.php on line 10

  I tried to manually include the composer autoload.php with :

  require_once 'vendor/autoload.php';

  However I get this error :

  Warning: require_once(vendor/autoload.php): failed to open stream: No such file or directory in /var/www/html/upload/test.php on line 6

  I found out that is because composer vendor is at root of apache.

  any help?

• FFMPEG Does not work on Windows Server 2008

  25 August 2011, by Khaldoun

  I have an ASP.NET MVC Web Site ,the user can upload a video and When Done It finish uploading I show him an image extracted from the Video,
  To do this I used the FFMPEG exe to get a frame.
  Everthing works well in the developement machine , when I use the test environement it does not work!!
  I've given the read/write and execute permissions to following folders:
  1. videos(folder that store uploaded video files)
  2. thumbnails (folder that store the thumbnails of videos, captured by ffmpeg)
  3.ffmpeg.exe file at root and given read/write execute permissions to that file also.
  but it does not work.

   var _converter = new ImageConvertor(@System.Configuration.ConfigurationManager.AppSettings["FFmpegExec"].ToString());
  
              _converter.WorkingPath = Server.MapPath("~/VideoSamples");
  
              OutputPackage oo = _converter.ConvertToFLV(videoFilepath);
  
              FileStream outStream = System.IO.File.OpenWrite(Path.Combine(Server.MapPath("~/VideoSamples"), id.ToString() + ".flv"));
  
              oo.VideoStream.WriteTo(outStream);

  This Code Works on developement env but not in test env !!!
  Any Ideas Please