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• The .mp4 video does not play, which is created from ffmpeg library (not command line)

  25 septembre 2013, par user1914692

  I use ffmpeg library to encode frames to a .mp4 video. The program runs smoothly without error. But the output .mp4 video does not play. Properties of the file does not even show it is a video file, no any information of video stream.

  The related code is :

  const char* ouVideoFileName = "output.mp4";
  
  AVCodecID ouCodec_id = CODEC_ID_H264;

  But if I change it to :

  const char* ouVideoFileName = "output.avi";
  
  AVCodecID ouCodec_id = CODEC_ID_H264;

  The .avi video plays correctly.

  What's wrong with .mp4 video ?

• catch percentage File conversion ffmpeg

  28 mai 2013, par offboard

  I've been thinking about implementing a new function on my system.
  so I thought to show the state of the file conversion.
  I thought of a logic to it.
  updating table from the database according to the percentage of file conversion.

  <?
  
  exec('ffmpeg -i p17prdvj251lk11d3v12ntijfq2u1.mp4 -vf scale=-1:360 -c:v libx264 -preset ultrafast output.flv');
  
  for($i = 0; $i <= 1; $i++){
  
      mysql_query("UPDATE progress SET pss='".$i."' WHERE id='1'");
  
  }

  the problem is that I do not know if it's possible to get the percentage.
  I thought about using the extension of ffmpeg and create a function to convert the files but do not know if it will work

• Calling ffmpeg api from Oracle

  1er mai 2012, par TenG

  I have installed ffmpeg and ffmpeg-devel packages on Linux.

  Oracle 11g is installed and running.

  The database stores media files, and for better streaming we need to convert them to AVI format.

  For ease of integration, we would like to do this conversion in the database.

  Now, the simplest option is to write a wrapper for the ffmpeg command line utility, and enable a PLSQL procedure to call this.

  However this would require the following steps :

  1. Read video BLOB
  2. Write to a OS file
  3. Call ffmpeg wrapper giving file name from (2) and output file name
  4. Load output file from 3 into a BLOB in PLSQL

  I would like to if possible write a C routine (using the Oracle External Library feature) which accepts the input as the BLOB (OciLOBLocator), calls the appropriate libavformat functions presenting the LOB, and write the return to a LOB (again OciLOBLOcator) which is what the PLSQL layer then uses as the AVI file.

  The other advantage of this is it avoids the undesirable impact of issuing a OS command from within Oracle.

  The problem I have is that the examples given for ffmpeg show the processing of data from files, whereas I need the libraries to process the LOBs.

  The alternative is to see if the OrdVideo data type in Oracle does this kind of conversion by using setformat and process.