Recherche avancée

Sur d’autres sites (6000)

• how to convert mp4 using ffmpeg for ios [on hold]

  23 août 2015, par Khaled Hayek

  I have problem to use ffmpeg for windows to convert mp4 file so that it can be played on iphone

      ffmpeg -i input.mkv -c:v libx264 -crf 28 -preset veryslow -tune fastdecode \
  
    -profile:v baseline -level 3.0 -movflags +faststart -c:a libfdk_aac -ac 2 \
  
    -ar 44100 -ab 64k -threads 0 -f mp4 output.mp4

  but still not working, any help please

• Streaming x264 with packet loss

  6 octobre 2014, par user2629511

  I write the program where I use x264 as the coder.
  I use the following parameters :

  av_opt_set (codecContextH264[numberCoder]-> priv_data, "profile", "baseline", 0);
  
  av_opt_set (codecContextH264[numberCoder]-> priv_data, "preset", "ultrafast", 0);
  
  av_opt_set (codecContextH264[numberCoder]-> priv_data, "tune", "zerolatency", 0);
  
  codecContextH264[numberCoder]-> bit_rate =bitrate;
  
  codecContextH264[numberCoder]-> bit_rate_tolerance=bitrate-5000;
  
  codecContextH264[numberCoder]-> width = w;
  
  codecContextH264[numberCoder]-> height = h;
  
  codecContextH264[numberCoder]-> time_base.den = fps;
  
  codecContextH264[numberCoder]-> time_base.num = 1;
  
  codecContextH264[numberCoder]-> pix_fmt = PIX_FMT_YUV420P;
  
  codecContextH264[numberCoder]-> gop_size = fps*3;
  
  codecContextH264[numberCoder]-> keyint_min = fps*3;
  
  codecContextH264[numberCoder]-> max_b_frames = 0; 
  
  codecContextH264[numberCoder]-> slices = (int) (w*h)/1500+1;

  I use only I and P frames.
  What x264 settings I shall use that could lose P frames ?
  Perhaps x264 has no such opportunity ?!
  I read that if to use a "base" profile, it is possible to lose P frames...
  Help please.

• real time video streaming in C#

  16 juin 2016, par Nuwan

  I’m developing an application for real time streaming. Two parts include for the streaming.
  I use a capture card to capture some live source and need to stream in real time.
  and also need to stream a local video file.

  To stream local video file in real time I use emgu cv to capture the video frame as bitmaps.
  To achieve this I create the bitmap list and I save captured bitmap to this list using one thread.
  and also I display those frames in a picture box. Bitmap list can store 1 second video. if frame rate is
  30 it will store 30 video frames. After filling this list I start another thread to encode that 1 second chunk
  video.

  For encoding purpose I use ffmpeg wrapper called nreco. I write that video frames to ffmpeg
  and start the ffmpeg to encode. After stopping that task I can get encoded data as byte array.

  Then I’m sending that data using UDP protocol through LAN.

  This works fine. But I cannot achieve the smooth streaming. When I received stream via VLC player there is some millisecond of delay between packets and also I noticed there a frame lost.

  private Capture _capture = null;
  
  Image frame;
  
  
  
  // Here I capture the frames and store them in a list
  
  private void ProcessFrame(object sender, EventArgs arg)
  
  {
  
       frame = _capture.QueryFrame();
  
       frameBmp = new Bitmap((int)frameWidth, (int)frameHeight, PixelFormat.Format24bppRgb);
  
       frameBmp = frame.ToBitmap(); 
  
  
  
  
  
   twoSecondVideoBitmapFramesForEncode.Add(frameBmp);
  
                          ////}
  
       if (twoSecondVideoBitmapFramesForEncode.Count == (int)FrameRate)
  
       {
  
           isInitiate = false;
  
           thread = new Thread(new ThreadStart(encodeTwoSecondVideo));
  
           thread.IsBackground = true;
  
           thread.Start();
  
       }  
  
   }
  
  
  
  public void encodeTwoSecondVideo()
  
  {
  
      List<bitmap> copyOfTwoSecondVideo = new List<bitmap>();
  
      copyOfTwoSecondVideo = twoSecondVideoBitmapFramesForEncode.ToList();
  
      twoSecondVideoBitmapFramesForEncode.Clear();
  
  
  
      int g = (int)FrameRate * 2;
  
  
  
      // create the ffmpeg task. these are the parameters i use for h264 encoding
  
  
  
          string outPutFrameSize = frameWidth.ToString() + "x" + frameHeight.ToString();
  
          //frame.ToBitmap().Save(msBit, frame.ToBitmap().RawFormat);
  
          ms = new MemoryStream();
  
          //Create video encoding task and set main parameters for the video encode
  
  
  
          ffMpegTask = ffmpegConverter.ConvertLiveMedia(
  
              Format.raw_video,
  
              ms,
  
              Format.h264,
  
              new ConvertSettings()
  
              {
  
  
  
                  CustomInputArgs = " -pix_fmt bgr24 -video_size " + frameWidth + "x" + frameHeight + " -framerate " + FrameRate + " ", // windows bitmap pixel format
  
                  CustomOutputArgs = " -threads 7 -preset ultrafast -profile:v baseline -level 3.0 -tune zerolatency -qp 0 -pix_fmt yuv420p -g " + g + " -keyint_min " + g + " -flags -global_header -sc_threshold 40 -qscale:v 1 -crf 25 -b:v 10000k -bufsize 20000k -s " + outPutFrameSize + " -r " + FrameRate + " -pass 1 -coder 1 -movflags frag_keyframe -movflags +faststart -c:a libfdk_aac -b:a 128k "
  
                  //VideoFrameSize = FrameSize.hd1080,
  
                  //VideoFrameRate = 30
  
  
  
              });
  
  
  
          ////////ffMpegTask.Start();
  
          ffMpegTask.Start();
  
  
  
  
  
        // I get the 2 second chunk video bitmap from the list and write to the ffmpeg 
  
    foreach (var item in copyOfTwoSecondVideo)
  
          {
  
              id++;
  
              byte[] buf = null;
  
              BitmapData bd = null;
  
              Bitmap frameBmp = null;
  
  
  
              Thread.Sleep((int)(1000.5 / FrameRate));
  
  
  
              bd = item.LockBits(new Rectangle(0, 0, item.Width, item.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
  
              buf = new byte[bd.Stride * item.Height];
  
              Marshal.Copy(bd.Scan0, buf, 0, buf.Length);
  
              ffMpegTask.Write(buf, 0, buf.Length);
  
              item.UnlockBits(bd);
  
          }
  
     }
  
  </bitmap></bitmap>

  This is the process I used to achieve the live streaming. But the stream is not smooth. I tried using a queue instead
  of list to reduce the the latency to fill the list. Because I thought that latency happens encoding thread encode
  and send 2 second video very quickly. But when it finishes this encoding process of bitmap list not
  completely full. So encoding thread will stop until the next 2 second video is ready.

  If any one can help me to figure this out, it is very grateful. If the way of I’m doing this is wrong, please correct me.
  Thank You !