Recherche avancée

Sur d’autres sites (6755)

• How can I quantitatively measure gstreamer H264 latency between source and display ?

  16 décembre 2014, par KevinM

  I have a project where we are using gstreamer , x264, etc, to multicast a video stream over a local network to multiple receivers (dedicated computers attached to monitors). We’re using gstreamer on both the video source (camera) systems and the display monitors.

  We’re using RTP, payload 96, and libx264 to encode the video stream (no audio).

  But now I need to quantify the latency between (as close as possible to) frame acquisition and display.

  Does anyone have suggestions that use the existing software ?

  Ideally I’d like to be able to run the testing software for a few hours to generate enough statistics to quantify the system. Meaning that I can’t do one-off tests like point the source camera at the receiving display monitor displaying a high resolution and manually calculate the difference...

  I do realise that using a pure software-only solution, I will not be able to quantify the video acquisition delay (i.e. CCD to framebuffer).

  I can arrange that the system clocks on the source and display systems are synchronised to a high accuracy (using PTP), so I will be able to trust the system clocks (else I will use some software to track the difference between the system clocks and remove this from the test results).

  In case it helps, the project applications are written in C++, so I can use C event callbacks, if they’re available, to consider embedding system time in a custom header (e.g. frame xyz, encoded at time TTT - and use the same information on the receiver to calculate a difference).

• ffmpeg Getting image or thumbnail from video error

  18 juillet 2013, par eMatsiyana

  i have a simple site on which people upload videos, so i want to generate a simple thumbnail from an uploaded video. i have tried every trick and way to do this from a number of websites but i am failing to make the command run without problems.

  $video = $_FILES['vpopupdropin']["tmp_name"];
  
      $ffmpeg = "C:\\Ffmpeg\\ffmpeg-20130605-git-3289670-win64-static\\bin";
  
      $image = "manu.jpg";
  
      $second = 12;
  
      $size = "150x90";
  
  $command = "$ffmpeg -i $video -an -ss $second -s $size -vcodec mjpeg      $image";
  
  echo $command;
  
      shell_exec($command);
  
  
  
      if(shell_exec($command)){
  
          echo 'okay';
  
          echo &#39;<img src="http://stackoverflow.com/feeds/tag/&#39;.$image.&#39;" style='max-width: 300px; max-height: 300px' /> >&#39;;
  
          }
  
  
  
      else{
  
          echo &#39; Problem&#39;;
  
          }

  i Echoed the the command from PHP and this is what i got :
  C :\Ffmpeg\ffmpeg-20130605-git-3289670-win64-static\bin -i C :\xampp\tmp\php27F1.tmp -an -ss 12 -s 150x90 -vcodec mjpeg manu.jpg Problem

  so i took the Command above and entered it in Cmd and got this error

  [image2 @ 00000000000000003d87580] Could not open file : manu.jpg
  av_interleaved_write_frame() : Input/output error. the uploaded file transfers well to where iam saving it and plays well on the site meaning the file is not corrupt. but the thumbnail command seems to fail, i have even checked the other questions on this site but i seem to fail to get the right solution. the paths in the Command are correct and i have verified that at least

• libavfilter/dnn/dnn_backend{openvino, tf} : check memory alloc non-NULL

  14 octobre 2020, par Chris Miceli

  libavfilter/dnn/dnn_backendopenvino, tf : check memory alloc non-NULL
  These previously would not check that the return value was non-null
  
  meaning it was susceptible to a sigsegv. This checks those values.
  

  • [DH] libavfilter/dnn/dnn_backend_openvino.c
  • [DH] libavfilter/dnn/dnn_backend_tf.c