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• lavc/qsvenc_hevc : restore the default gop size

  11 août 2023, par Haihao Xiang

  lavc/qsvenc_hevc : restore the default gop size
  commit a3c0a3e changed the default settings and expected the runtime can
  
  choose a best value. However the runtime doesn't set a valid gop size
  
  for hevc encoder, hence the output steam is non-seekable, which is
  
  inconvenient to user [1][2]
  [1] https://github.com/intel/media-driver/issues/1576
  
  [2] https://ffmpeg.org/pipermail/ffmpeg-user/2023-August/056716.html
  Signed-off-by : Haihao Xiang <haihao.xiang@intel.com>
  

  • [DH] libavcodec/qsvenc_hevc.c

• FFmpeg what exactly is the filtergraph pipeline like during transcoding ?

  8 septembre 2017, par Jeff Gong

  I have been studying the source code for FFmpeg to attempt to understand its threading model and how it processes inputs. For example, when I run a command like :

  ffmpeg -i video.mp4 -s hd720 -c:v libx264 --preset medium -c:a aac -profile:v main -r 60 -f null /dev/null

  The input itself is irrelevant, but I am trying to understand how the transcoding pipeline works. In the source code, I see that the main steps occur in the functions transcode and transcode_step.

  It seems like for a single input, a single frame is read in, decoded, encoded, and written out. The process is obviously very complex but what I am really not understanding is what FFmpeg is doing when it attempts to build out a filtergraph. For example, in transcode_step of ffmpeg.c, there is the following code that happens right after an output stream has been selected :

  if (ost->filter && !ost->filter->graph->graph) {
  
      if (ifilter_has_all_input_formats(ost->filter->graph)) {
  
          ret = configure_filtergraph(ost->filter->graph);
  
          if (ret < 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Error reinitializing filters!\n");
  
              return ret;
  
          }
  
      }
  
  }

  Does this only apply if I specify a specific series of filtering options to FFmpeg, like the one in this link ? For the sample command I input above, is this code still executed ?

  One last other question I had was for the case where I run an FFmpeg instance with a single input but multiple outputs (perhaps different variants for transcoding). In this scenario, does a single phase of transcode_step take in an input frame and send that frame through decoding and encoding for only a single one of the outputs ? Or does it take a frame at a time and process this frame for each of the outputs we have specified ?

• Unable to Watermark an Uploaded Video Using protonemedia / laravel-ffmpeg

  24 avril 2021, par Kashif Anwar

  I am trying to watermark a video to prevent users from downloading the original video.

  


  Below is my code for uploading a video, followed by watermarking it :

  


  public function watermarkpost(Request $request)
{

    if ($file = $request->file('watermark')) 
    {      
       $name = time().str_replace(' ', '', $file->getClientOriginalName());
       $file->move('assets/images/products',$name);           
    }
        FFMpeg::open(asset('assets/images/products/'.$name))->addWatermark(function(WatermarkFactory $watermark) {
            $watermark
            ->open(asset('assets/images/1571567292logo.png') )
            ->right(25)
            ->bottom(25);
        });
   
    // return asset('assets/images/products/'.$name);
}


  


  The error :

  


  Alchemy\\BinaryDriver\\Exception\\ExecutableNotFoundException(code: 0): Executable not found, proposed : ffmpeg at F:\\xampp\\htdocs\\GeniusCart\\project\\vendor\\alchemy\\binary-driver\\src\\Alchemy\\BinaryDriver\\AbstractBinary.php:159)


  


  How to resolve this issue ?