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• While ffmpeg convers via php website doesnt work

  29 octobre 2013, par Xenos Trojanowicz

  So im using

                  if ($success_msg) 
  
              {
  
                  $tmp_parts = explode('.', $file['name']);
  
                  $ext = array_pop($tmp_parts);
  
                  $ext = strtolower($ext);
  
                  if($ext == "avi" && $convert_avi == true)
  
                      {
  
                          $convert_source = _VIDEOS_DIR_PATH.$new_name;
  
                          $conv_name = substr(md5($file['name'].rand(1,888)), 2, 10).".mp4";
  
                          $converted_file  = _VIDEOS_DIR_PATH.$conv_name;
  
                          $ffmpeg_command = 'ffmpeg -i '.$convert_source.'-acodec libfaac -vcodec libx264 -s 1280x720 -ar 44100 -async 44100 -r 29.970 -ac 2 -qscale 5 '.$converted_file;
  
                          echo exec($ffmpeg_command);
  
                          $sql = "UPDATE pm_temp SET url = '".$conv_name."' WHERE url = '".$new_name."' LIMIT 1";
  
                          $result = @mysql_query($sql);
  
                          unlink($convert_source);    
  
                      }
  
                  echo $success_msg;
  
              }

  This code to convert videos from avi to mp4 but i have another big issue when i upload big file let say 170 mb it converts about 25 minutes or so and while it converts website doesnt work for me.

  NOW I KNOW WHY WEBSITE DOESNT WORK :

  • its only for me becose system doesnt open extra slot to enter to website while it converts
  • i know how to solve this problem with cronjob but im afraid that if something goes wrong it will be biggest fail i ever had

  so im hopping that u guys will suggest something smart and easy to deal with this issue

• Is it safe to set AVPacket::duration to one ?

  9 septembre 2021, par Vivekanand V

  I am new to the world of programming of multimedia applications. I just managed to get a hold of FFMPEG's libraries to perform video encoding and decoding in C/C++ and I feel that I have a lack of understanding in many aspects of the whole process.

  


  My application converts an RGB24 array referenced by unsigned char* to a AVFrame, and encodes it to a video file.

  


  During initialization, I set the time base in codec context to 1/fps, where fps is the frame rate.

  


  AVStream::time_base is also set to the same value.

  


  Is there is a mathematical relationship between these time bases to AV_TIME_BASE constant ?

  


  How should AVFrame::pts be set. Here I am just incrementing by one for every encoding operation.

  


  How should AVPacket::duration be set, before calling av_interleaved_write_frame ?

  


  What is the significance of AVPacket::pts and AVPacket::dts ?

  


• {OpenAL(+FFmpeg)} How to queue variable size buffer due to ogg format ?

  11 février 2014, par user3293833

  (First of all, I may feel sorry about my poor English as it's not my native language.)

  I use FFmpeg to decode some audio file and play it with OpenAL by "stream"(i.e."queue" and "unqueue" function of OpenAL).

  When I use my program to play .ogg file, I find that it has a variable nb_samples.(due to ogg has variable bit rate ??) There are 128 B, 512 B and 1024 B of nb_samples. As a results, I must call alDeleteBuffers and alGenBuffers before I use alBufferSamplesSOFT(similar to alBufferData) because it would fail to call alBufferSamplesSOFT without recreate the buffer.
  Notes : alBufferSamplesSOFT is provided by OpenAL Soft. You can just see it as alBufferData.

  Nevertheless, I think it's foolish and inefficient if I do this. Is there is some smart method ? I paste the part of code :

  while (av_read_frame(...) == 0){
  
    avcodec_decode_audio4(...);
  
    swr_convert(...);  // to convert PCM format from FLTP to FLT
  
    alDeleteBuffers(1, theBuffers[?]);
  
    alGenBuffers(1, theBuffers[?]);
  
    alBufferSamplesSOFT(...);  // put those data into OpenAL buffer
  
  }

  if I don't do this, It would failed to update the OpenAL buffer. Is there any method to create a variable size buffer or a big size buffer ? Or is there any method to change the size of buffer ?

  Thanks for you guys.