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• lavu/tx : implement 32 bit fixed point FFT and MDCT

  9 février 2020, par Lynne

  lavu/tx : implement 32 bit fixed point FFT and MDCT
  Required minimal changes to the code so made sense to implement.
  
  FFT and MDCT tested, the output of both was properly rounded.
  
  Fun fact : the non-power-of-two fixed-point FFT and MDCT are the fastest ever
  
  non-power-of-two fixed-point FFT and MDCT written.
  
  This can replace the power of two integer MDCTs in aac and ac3 if the
  
  MIPS optimizations are ported across.
  
  Unfortunately the ac3 encoder uses a 16-bit fixed point forward transform,
  
  unlike the encoder which uses a 32bit inverse transform, so some modifications
  
  might be required there.
  The 3-point FFT is somewhat less accurate than it otherwise could be,
  
  having minor rounding errors with bigger transforms. However, this
  
  could be improved later, and the way its currently written is the way one
  
  would write assembly for it.
  
  Similar rounding errors can also be found throughout the power of two FFTs
  
  as well, though those are more difficult to correct.
  
  Despite this, the integer transforms are more than accurate enough.
  

  • [DH] doc/APIchanges
  • [DH] libavutil/Makefile
  • [DH] libavutil/tx.c
  • [DH] libavutil/tx.h
  • [DH] libavutil/tx_int32.c
  • [DH] libavutil/tx_priv.h
  • [DH] libavutil/tx_template.c
  • [DH] libavutil/version.h

• PHP upload video files to database

  13 janvier 2016, par Mick Jack

  I am working on a school project that let users upload video files to a server. Server will compress the video using ffmpeg and store the file in upload folder. Other users will be able to stream the uploaded videos.

  My question is how do i retrieve the video that ffmpeg generated and store the link in the database ?

  i am using this code but it only retrieve path of the original video.

  $filePath = dirname(__FILE__); 

  partial code of Upload.php

  $target_dir = "upload/"; //where you want to upload the files to
  
  $target_file = $target_dir.basename($_FILES['file']['name']);
  
  $fileType = pathinfo($target_file, PATHINFO_EXTENSION);
  
  $newFileName = $target_dir.sha1(pathinfo(basename($_FILES['file']['name']), PATHINFO_FILENAME)).'-'.time().'.'.$fileType;
  
  move_uploaded_file($_FILES['file']['tmp_name'], $newFileName);
  
  $unique_id = rand(1000000,9999999);
  
  
  
  shell_exec("C:\\ffmpeg\\bin\\ffmpeg.exe -i ".$newFileName." -vcodec libx264 -crf 20 \"upload\\{$newFileName}\" > logfile.txt 2>&1");
  
  
  
  /// save information into database
  
                  $username = "root";
  
                  $password = "";
  
                  $hostname = "localhost"; 
  
                  $dbname = "test_database";
  
  
  
                  //connect to the database
  
                  $dbc = mysqli_connect($hostname, $username, $password, $dbname) or die ("could not connect to the database");
  
  
  
                  //execute the SQL query and return records
  
                   $result = mysqli_query($dbc, "INSERT INTO `viewvideo` (`vID`, 'video_id`, `video_link`) VALUES ('', '".$unique_id."', '".$newFileName."')");
  
  
  
                  if(!$result){echo mysqli_error($dbc); }
  
  
  
                  echo $result;
  
  
  
              /*  
  
                  declare in the order variable
  
                  $result = mysqli_query($dbc, $sql); //order executes
  
                  if($result){
  
                      echo("<br />Input data is succeed");
  
                  } else{
  
                      echo("<br />Input data is fail");
  
                  }
  
              */  
  
  
  
                  //close the connection
  
                  mysqli_close($dbc);

  output
  

• How to create a clip from an mp4-file quickly ?

  26 mars 2023, par Moritz Groß

  I have a web app that lets users download a clip from a mp4-file specified before. Currently I use ffmpeg via python like this :

  


  os.system('ffmpeg -i original_video -ss {start} -t {duration} result_video')


  


  Processing 10 minutes of 720p video with this method also takes a few minutes (during the execution, ffmpeg displays speed=3x on average). Does this mean processing 10 minutes of video takes 3minutes & 20 seconds as I understand it ?

  


  Is this slow of a performance expected ? Can I improve it by using an other filetype than mp4 ?