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• FFmpeg dash manifest '-window_size'

  14 novembre 2018, par edwinbradford

  In the FFmpeg DASH documentation I don’t understand the purpose of -window_size which is explained as :

  Set the maximum number of segments kept in the manifest.

  If my video is 30 seconds long, the GOP size is 4 seconds and the segment length is 4 seconds, what is the meaning and purpose of a parameter to control the maximum number of segments kept in the manifest, when does this parameter need to be used and how do you determine valid values ?

  I’m guessing that the stream is being loaded into memory and the number of segments in the manifest controls how much is kept in memory at one time but it’s just a wild guess and I can’t find any further explanation.

  I am not live streaming in case it’s relevant.

• Trying to upload a video to a server and then play it back to a video view (Xamarin android)

  31 juillet 2016, par stackOverNo

  I’m currently working on a xamarin.android project, and am attempting to upload a video to an aws server, and then also be able to play it back. The upload is working correctly as far as I can tell.

  I’m retrieving the file from the user’s phone, turning it into a byte array, and uploading that. This is the code to upload :

  if (isImageAttached || isVideoAttached)
  
              {
  
                  //upload the file 
  
                  byte[] fileInfo = System.IO.File.ReadAllBytes(filePath);
  
                  Task<media> task = client.SaveMediaAsync(fileInfo, nameOfFile);
  
                  mediaObj = await task;
  
  
  
                  //other code below is irrelevant to example
  
              }
  
  </media>

  and SaveMediaAsync is a function I wrote in a PCL :

  public async Task<media> SaveMediaAsync(byte[] fileInfo, string fName)
  
      {        
  
          Media a = new Media();
  
          var uri = new Uri(RestUrl);
  
  
  
          try
  
          {
  
  
  
              MultipartFormDataContent form = new MultipartFormDataContent();
  
              form.Add(new StreamContent(new MemoryStream(fileInfo)), "file", fName);  //add file
  
  
  
              var response = await client.PostAsync(uri, form);            //post the form   client is an httpclient object
  
              string info = await response.Content.ReadAsStringAsync();
  
  
  
      //save info to media object
  
              string[] parts = info.Split('\"');
  
              a.Name = parts[3];
  
              a.Path = parts[7];
  
              a.Size = Int32.Parse(parts[10]);
  
  
  
          }
  
          catch(Exception ex)
  
          {
  
      //handle exception
  
          }
  
  
  
          return a;
  
  
  
      }
  
  </media>

  After uploading the video like that, I’m able to view it in a browser using the public url. The quality is the same, and there is no issue with lag or load time. However when I try to play back the video using the same public url on my app on an android device, it takes an unbelievably long time to load the video. Even once it is loaded, it plays less than a second of it, and then seems to start loading the video again(the part of the progress bar that shows how much of the video has loaded jumps back to the current position and starts loading again).

   VideoView myVideo = FindViewById<videoview>(Resource.Id.TestVideo);
  
  
  
   myVideo.SetVideoURI(Android.Net.Uri.Parse(url));
  
  
  
   //add media controller
  
   MediaController cont = new MediaController(this);
  
   cont.SetAnchorView(myVideo);
  
   myVideo.SetMediaController(cont);
  
  
  
   //start video
  
   myVideo.Start();
  
  </videoview>

  Now I’m trying to play a 15 second video that is 5.9mb. When I try to play a 5 second video that’s 375kb it plays with no issue. This leads me to believe I need to make the video file smaller before playing it back, but I’m not sure how to do that. I’m trying to allow the user to upload their own videos, so I’ll have all different file formats and sizes.

  I’ve seen some people suggesting ffmpeg for a c# library to alter video files, but I’m not quite sure what it is I need to do to the video file. Can anyone fill in the gaps in my knowledge here ?

  Thanks for your time, it’s greatly appreciated !

• avcodec/h264_mp4toannexb : Prepend SPS/PPS to buffering period SEI

  1er août 2024, par Josh Allmann

  avcodec/h264_mp4toannexb : Prepend SPS/PPS to buffering period SEI
  Encoders may emit a buffering period SEI without a corresponding
  
  SPS/PPS if the SPS/PPS is carried out-of-band, eg with avcc.
  During Annex B conversion, this may result in the SPS/PPS being
  
  inserted *after* the buffering period SEI but before the IDR NAL.
  Since the buffering period SEI references the SPS, the SPS/PPS
  
  needs to come first.
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DH] libavcodec/bsf/h264_mp4toannexb.c
  • [DH] tests/ref/fate/h264-bsf-mp4toannexb
  • [DH] tests/ref/fate/h264_mp4toannexb_ticket2991
  • [DH] tests/ref/fate/segment-mp4-to-ts