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• How to extract stream of images from video file using ffmpeg

  13 décembre 2013, par user3032143

  I want to extract stream of images from a video file using ffmpeg.

  I know I can extract them straight to the hard drive using these arguments :

  -i - -qscale 1 h :\out\img-%05d.jpg

  But i would like to extract directly to a stream.

  This is my code so far :

  private void ExtractImagesFromVideo(byte[] data,string _args)
  
      {
  
          try
  
          {
  
              serverBuild = new Process();
  
              serverBuild.StartInfo.WorkingDirectory = Environment.CurrentDirectory;
  
              serverBuild.StartInfo.Arguments = _args;
  
              serverBuild.StartInfo.FileName = Environment.CurrentDirectory + @"\ffmpeg.exe";
  
              serverBuild.StartInfo.UseShellExecute = false;
  
              serverBuild.StartInfo.RedirectStandardOutput = true;
  
              serverBuild.StartInfo.RedirectStandardError = true;
  
              serverBuild.StartInfo.RedirectStandardInput = true;
  
              serverBuild.StartInfo.CreateNoWindow = true;
  
              serverBuild.StartInfo.LoadUserProfile = false;
  
              serverBuild.EnableRaisingEvents = true;
  
              serverBuild.Start();
  
  
  
              using (BinaryWriter bw = new BinaryWriter(serverBuild.StandardInput.BaseStream))
  
              {
  
                  bw.Write(data);
  
              }
  
  
  
              mStandardOutput = serverBuild.StandardOutput.BaseStream;
  
              mStandardOutput.BeginRead(mReadBuffer, 0, mReadBuffer.Length, StandardOutputReadCallback, null);
  
              serverBuild.WaitForExit();
  
              byte[] _data = mStandardOutputMs.ToArray();
  
              mStandardOutput.Close();
  
  
  
          }
  
          catch (Exception _ex)
  
          {
  
  
  
          }
  
          finally
  
          {               
  
              serverBuild.Dispose();
  
          }
  
      }

  and I call like like this :

       string _argsOut = @"-i pipe:0 -qscale 1 -f mjpeg pipe:1 ";
  
       ExtractImagesFromVideo(data, _argsOut);

  and it hangs on this line :

  bw.Write(data);

  thanks

• Why aren't the videos in my S3 bucket buffering to html video tag ?

  2 juin 2019, par Michael Cain

  I have so far successfully programmed a node script on a Udoo x86 advanced plus that captures an Ethernet connected IP cam’s RTSP stream. I use ffmpeg to trans-code the stream into 5 second mp4 files. As soon as the files show up in the folder they are uploaded/synced to my AWS S3 Bucket. Next I have a Node server that GET’s the most recently created mp4 file from the S3 bucket and runs it through mediasource extension and finally to an html video tag.

  The videos are playing on the browser but not in any kind of synchronous manner. No buffering seems to be taking place. one video plays then another and so on. Video is skipping all over the place.

  I would really appreciate any guidance with this bug.

  export function startlivestream() {
  
    const videoElement = document.getElementById("my-video");
  
    const myMediaSource = new MediaSource();
  
    const url = URL.createObjectURL(myMediaSource);
  
    videoElement.src = url;
  
    myMediaSource.addEventListener("sourceopen", sourceOpen);
  
  }
  
  function sourceOpen() {
  
    if (window.MediaSource.isTypeSupported(
  
        'video/mp4; codecs="avc1.42E01E, mp4a.40.2"'
  
      )
  
    ) 
  
  {
  
         console.log("YES");
  
    }
  
  
  
  // 1. add source buffers
  
  
  
    const mediaCodec = 'video/mp4; codecs="avc1.4D601F"';
  
    var mediasource = this;
  
    const videoSourceBuffer = mediasource.addSourceBuffer(mediaCodec);
  
  
  
  // 2. download and add our audio/video to the SourceBuffers
  
  
  
  function checkVideo(url) {
  
    var oReq = new XMLHttpRequest();
  
      oReq.open("GET", url, true);
  
      oReq.responseType = "arraybuffer";
  
  
  
       oReq.onload = function(oEvent) {
  
        var arrayBuffer = oReq.response; // Note: not oReq.responseText
  
        if (arrayBuffer) {
  
           videoSourceBuffer.addEventListener("updateend", function(_) {
  
             mediasource.endOfStream();
  
             document.getElementById("my-video").play();
  
     });
  
             videoSourceBuffer.appendBuffer(arrayBuffer);
  
        }
  
      };
  
  
  
      oReq.send(null);
  
    }
  
  
  
    setInterval(function() {
  
      checkVideo("http://localhost:8080");
  
    }, 5000);

  My ffmpeg tags :

  const startRecording = () => {
  
    const args = [
  
      "-rtsp_transport",
  
      "tcp",
  
      "-i",
  
      inputURL,
  
      "-f",
  
      "segment",
  
      "-segment_time",
  
      "5",
  
      "-segment_format",
  
      "mp4",
  
      "-segment_format_options",
  
      "movflags=frag_keyframe+empty_moov+default_base_moof",
  
      "-segment_time",
  
      "5",
  
      "-segment_list_type",
  
      "m3u8",
  
      "-c:v",
  
      "copy",
  
      "-strftime",
  
      "1",
  
      `${path.join(savePath, "test-%Y-%m-%dT%H-%M-%S.mp4")}`
  
    ];

  From what I have learned about Mediasource extensions they allow multiple videos to be taken in and allow the client to buffer them so it looks like one longer video. In simple terms.

• How to pass BytesIO image objects to ffmpeg ?

  13 avril 2023, par Mr.Slow

  I a have a (nested) list od BytesIO objects (images) that I would like to pass to ffmpeg and make a video. I do know, the ffmpeg cannot take it straight. What should I convert it in first ? There might be a better way using 'pipe :', which I did not succeed to implement yet.
(in this example code I ignore image duration and audio, too)

  


  def merge_videos(file_id: float, audio_list: List[BinaryIO], duration_list: List[float], images_nested_list):
    # flatten the nested list of images
    images_list = [image for images_sublist in images_nested_list for image in images_sublist]
    
    additional_parameters = {'c:a': 'aac', 'c:v': 'libx264'}

    # Create a BytesIO object to hold the output video data
    output_data = io.BytesIO()

    # create the FFmpeg command with the specified parameters and pipe the output to the BytesIO object
    command = ffmpeg.output(*images_list, '-', vf='fps=10,format=yuv420p', preset='veryfast', shortest=None, r=10, max_muxing_queue_size=4000, **additional_parameters).pipe(output_data)

    try:
        # run the FFmpeg command with error and output capture
        subprocess.check_output(['ffmpeg', '-y', '-f', 'concat', '-safe', '0', '-i', 'audio.txt', '-i', '-', '-c:v', 'copy', '-c:a', 'aac', f"{PROJECT_PATH}/data/final-{file_id}.mp4"], input=output_data.getvalue())
        log.info("Final video with file_id %s has been converted successfully", file_id)


  


  ...this code returns :

  


  TypeError: Expected incoming stream(s) to be of one of the following types: ffmpeg.nodes.FilterableStream; got <class>&#xA;</class>

  


  How to handle it please ? Thanks for help.