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• Install ffmpeg on Heruko

  5 octobre 2020, par islalobo

  I have a little node.js app on heroku and I'm trying to use ffmpeg to convert some audio that has been recorded.

  


  To do that I need to install ffmpeg buildpack.

  


  When I add the build pack and deploy, I don't get any errors in the logs, but the application doesn't load and gives me a non-discript error.

  


  Build packs I've tried

  


  

  • https://elements.heroku.com/buildpacks/jonathanong/heroku-buildpack-ffmpeg-latest

  


  • https://elements.heroku.com/buildpacks/dwnld/heroku-buildpack-ffmpeg

  


  


  Code to convert audio

  


    try {
    let process = new ffmpeg(`./public/messages/${req.body.message}`);
    process.then((audio) => {
      audio.fnExtractSoundToMP3(`/messages/${req.body.message}.mp3`, (error, file) => {
        if (!error) console.log('Audio File: ', file);
        if (error) console.log(error);
      });
    }, (error) => {
      console.log('Error: ', error);
    });
  }
  catch(error) {
    console.log(error.code, error.msg);
  }


  


• How to stream mp4 files over RTSP ?

  21 février 2023, par Ramil Galin

  I wrote an RTSP server and now I want to stream mp4 (H264/AAC) files over it. Using FFMPEG I demux mp4 file into audio and video streams. Then I read AVPacket packets, wrap them into rtp packets and send over RTSP server.

  


  So far I'm just trying to send only video packets. I tried to get my RTSP stream using VLC, unfortunately VLC doesn't play anything. Then I tried to put my RTSP stream into the ffmpeg and save my stream into another mp4 file to see what happens with my packets - ffmpeg showed error no start code is found.

  


  I googled the issue and found that mp4 container unlike raw h264 doesn't put SPS/PPS info into the packets. To test it I tried the following. Instead of mp4 file I tried reading raw h264 files and send them over my RTSP server - it worked nicely, I can play my stream using VLC.

  


  So, my question is how can I get SPS/PPS info from mp4 container files ? How to correctly pack them into rtp packet and send over RTSP ?

  


  So far I tried to get sps and pps data using this code :

  


  AVCodecParameters *codecpar = video_stream->codecpar;
for (int i = 0; i < codecpar->extradata_size - 4; i++)
{

  if (
    codecpar->extradata[i] == 0x00 &&
    codecpar->extradata[i + 1] == 0x00 &&
    codecpar->extradata[i + 2] == 0x00 &&
    codecpar->extradata[i + 3] == 0x01
  )
  {
    if (sps_data_ == nullptr)
    {
      sps_data_ = codecpar->extradata + i;
      sps_size_ = i > 0 ? i : codecpar->extradata_size;
    }
    else
    {
      pps_data_ = codecpar->extradata + i;
      pps_size_ = i > 0 ? i : codecpar->extradata_size - sps_size_;
      break;
    }
  }
}


  


  But codecpar->extradata doesn't contain needed info, so if-condition inside the loop is always false. Any help is appreciated.

  


• Size Discrepany in the ‘du’ Command

  22 juin 2012, par Multimedia Mike — General

  I had a problem today while using the common Unix command ’du’. As a refresher, ’du’ stands for disk usage and is a handy tool for understanding how much disk space is being occupied.

  I think ’du’ is probably doing the right thing. The problem might be that I’m getting strange (read : 1/2 the expected number) when running the tool against directories on vmhgfs, the VMware filesystem.

  Science Project
  On an Ubuntu Linux VMware session, my home directory is on the main file system, which is ext4. The directory /mnt/hgfs is reported by ’mount’ to be of type vmhgfs and is shared with the host machine.

  Create a directory in the home directory and generate a 10 MiB file :

  mkdir /home/melanson/dir
  dd if=/dev/urandom of=/home/melanson/dir/random-file bs=1048576 count=10
  

  Create a directory on the shared drive and copy the same file :

  mkdir /mnt/hgfs/vmshare/dir
  cp /home/melanson/dir/random-file /mnt/hgfs/vmshare/dir
  

  Run ’du’ on each directory using the -k and -h options :

  du -k /home/melanson/dir /mnt/hgfs/vmshare/dir
  10244   /home/melanson/dir
  5120    /mnt/hgfs/vmshare/dir
  du -h /home/melanson/dir /mnt/hgfs/vmshare/dir
  
  11M    /home/melanson/directory
  
  5.0M   /mnt/hgfs/vmshare/directory
  

  I noticed this discrepancy when I was trying to pack a set of files (akin to ’tar’-ing) living in a directory in the shared location. I was going mad trying to understand why the original directory was only 2 MB as reported by ’du’ but the final packed file was 4 MB.

  To be fair, the man page for ’du’ succinctly states that the tool’s purpose is merely to "estimate file space usage".