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• Is it possible to save snapshots from multiple video streams using ffmpeg ?

  14 novembre 2023, par Haydn Morris

  I would like to periodically save a snapshot from a video stream using ffmpeg. This is is possible using the following command :

  


  ffmpeg -i [source] -r 0.2 -f image2 ./image-%04d.jpeg

  


  or the (rough) equivalent in ffmpge-python :

  


  ffmpeg.input(source, **inputArgs)
    .filter("fps", fps=1 / 5, round="up")
    .output("./image-%04d.jpeg")


  


  I would like to do this for N input streams simultaneously. So, I would be saving 1 frame every 5 seconds for each of the input streams. Is this possible using ffmpeg or ffmpeg-python ? I can't find any examples with multiple input streams.

  


  Just for some more information : the sources are all rtsp streams and N can be between 10 and 60. I also would like to limit the number of files on disk at any one time (similar to G-streamer's max-files property) but this is less important.

  


• How to Save and Display a Video Simultaneously using C# Aforge.NET framework ?

  8 avril 2014, par Akshay

  I am able to display the video from my webcam or any other integrated device into a picturebox . Also i am able to Save the video into an avi file using FFMPEG DLL files.
  I want to do both things simultaneously ie Save the video in the avi file as well as at the same time display the live feed too.
  This is for a surveillance project where i want to monitor the live feed and save those too.

  using System;
  
  using System.Collections.Generic;
  
  using System.ComponentModel;
  
  using System.Data;
  
  using System.Drawing;
  
  using System.Text;
  
  using System.Windows.Forms;
  
  
  
  using AForge.Video;
  
  using AForge.Video.DirectShow;
  
  using AForge.Video.FFMPEG;
  
  using AForge.Video.VFW;
  
  using System.Drawing.Imaging;
  
  using System.IO;
  
  
  
  namespace cam_aforge1
  
  {
  
  public partial class Form1 : Form
  
  {
  
      private bool DeviceExist = false;
  
      private FilterInfoCollection videoDevices;
  
      private VideoCaptureDevice videoSource = null;
  
  
  
      public Form1()
  
      {
  
          InitializeComponent();
  
      }
  
  
  
      private void getCamList()
  
      {
  
          try
  
          {
  
              videoDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice);
  
              comboBox1.Items.Clear();
  
              if (videoDevices.Count == 0)
  
                  throw new ApplicationException();
  
  
  
              DeviceExist = true;
  
              foreach (FilterInfo device in videoDevices)
  
              {
  
                  comboBox1.Items.Add(device.Name);
  
              }
  
              comboBox1.SelectedIndex = 0; //make dafault to first cam
  
          }
  
          catch (ApplicationException)
  
          {
  
              DeviceExist = false;
  
              comboBox1.Items.Add("No capture device on your system");
  
          }
  
      }
  
  
  
      private void rfsh_Click(object sender, EventArgs e)
  
      {
  
          getCamList();
  
      }
  
  
  
      private void start_Click(object sender, EventArgs e)
  
      {
  
          if (start.Text == "&Start")
  
          {
  
              if (DeviceExist)
  
              {
  
                  videoSource = new VideoCaptureDevice(videoDevices[comboBox1.SelectedIndex].MonikerString);
  
                  videoSource.NewFrame += new NewFrameEventHandler(video_NewFrame);
  
                  videoSource.NewFrame += new NewFrameEventHandler(video_NewFrameSave);
  
                  CloseVideoSource();
  
                  videoSource.DesiredFrameSize = new Size(160, 120);
  
                  //videoSource.DesiredFrameRate = 10;
  
                  videoSource.Start();
  
                  label2.Text = "Device running...";
  
                  start.Text = "&Stop";
  
                  timer1.Enabled = true;
  
              }
  
              else
  
              {
  
                  label2.Text = "Error: No Device selected.";
  
              }
  
          }
  
          else
  
          {
  
              if (videoSource.IsRunning)
  
              {
  
                  timer1.Enabled = false;
  
                  CloseVideoSource();
  
                  label2.Text = "Device stopped.";
  
                  start.Text = "&Start";                    
  
              }
  
          }
  
      }
  
      private void video_NewFrame(object sender, NewFrameEventArgs eventArgs)
  
      {
  
          Bitmap img = (Bitmap)eventArgs.Frame.Clone();
  
          pictureBox1.Image = img;
  
      }
  
  
  
      Bitmap imgsave;
  
      private void video_NewFrameSave(object sender, NewFrameEventArgs eventArgs)
  
      {
  
          imgsave = (Bitmap)eventArgs.Frame.Clone();
  
      }
  
  
  
      private void CloseVideoSource()
  
      {
  
          if (!(videoSource == null))
  
              if (videoSource.IsRunning)
  
              {
  
                  videoSource.SignalToStop();
  
                  videoSource = null;
  
              }
  
      }
  
  
  
      private void timer1_Tick(object sender, EventArgs e)
  
      {
  
          label2.Text = "Device running... " + videoSource.FramesReceived.ToString() + " FPS";
  
      }
  
  
  
      private void Form1_FormClosed(object sender, FormClosedEventArgs e)
  
      {
  
          CloseVideoSource();
  
      }
  
  
  
      private void Form1_Load(object sender, EventArgs e)
  
      {
  
  
  
      }
  
  
  
      VideoFileWriter writer;
  
  
  
      private void button1_Click(object sender, EventArgs e)
  
      {
  
          int width = 640;
  
          int height = 480;
  
          writer = new VideoFileWriter();
  
          writer.Open("test.avi", width, height, 75, VideoCodec.MPEG4);
  
          for (int i = 0; i < 5000; i++)
  
          {
  
              writer.WriteVideoFrame(imgsave);
  
          }
  
  
  
      }
  
  
  
      private void button2_Click(object sender, EventArgs e)
  
      {
  
          writer.Close();
  
      }
  
  
  
  }
  
  }

  Thanks in advance.

• FFmpeg - What muxer do i need to save an AAC audio stream

  3 août 2022, par David Barishev

  I'm developing Android application, and im using ffmpeg for conversion of files.
  
I want my binary file to be as slim as possible since i don't have many input formats and output formats, and my operation is quite basic.And of course not to bloat the APK.

  



  In my program ffmpeg receives a file, and copys the audio stream (-acodec copy), the audio stream will always be aac (mp4a). What i need is to save the stream to file.
  
My command looks like this : ffmpeg -i {Input} -vn -acodec copy output.aac.

  



  What muxer do i need to for muxing aac to file ? I have tried flv,mp3,mov but i always get
  
Unable to find a suitable output format for 'output.aac', so these options are wrong.
  
I don't need an encoder for stream copy btw.

  



  Side note : this command work flawlessly on full installation of ffmpeg , but I don't know which muxer it uses. If there is a way to output the muxer it uses from regular ffmpeg run, it would work too.