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• Saving individual frames of multiple m3u8 streams

  10 décembre 2023, par Toprak

  I have a list of multiple m3u8 stream URLs. I want to grab individual live frames of these streams and save them locally. I managed to do this with openCv however, the number of streams is around 20, even though I wrote the code using parallel processing and multithreading, some streams wait too long to download the new frames.

  


  Is there a better way or faster module that I can use ? Theoretically it shouldn't be this hard because I can open each stream in browser and the client side player can stream it. I feel like maybe ffmpeg is a solution, but I couldn't find a way to download and save each frame from a stream link by ffmpeg, with a unique name so. it doesn't update all the time.

  


  Edit :
I attempted to this issue with ffmpeg as well, using multithreading , but probably because each time they want to grab a frame, they need to connect, this is slower.

  


  ffmpeg -i url.m3u8 -vframes 1 -q:v 2 output.jpg

  


• On-demand and seamless transcoding of individual HLS segments

  5 janvier 2024, par Omid Ariyan

  Background

  


  I've been meaning to implement on-demand transcoding of certain video formats such as ".mkv", ".wmv", ".mov", etc. in order to serve them on a media management server using ASP.NET Core 6.0, C# and ffmpeg.

  


  My Approach

  


  The approach I've decided to use is to serve a dynamically generated .m3u8 file which is simply generated using a segment duration of choice e.g. 10s and the known video duration. Here's how I've done it. Note that the resolution is currently not implemented and discarded :

  


  public string GenerateVideoOnDemandPlaylist(double duration, int segment)
{
   double interval = (double)segment;
   var content = new StringBuilder();

   content.AppendLine("#EXTM3U");
   content.AppendLine("#EXT-X-VERSION:6");
   content.AppendLine(String.Format("#EXT-X-TARGETDURATION:{0}", segment));
   content.AppendLine("#EXT-X-MEDIA-SEQUENCE:0");
   content.AppendLine("#EXT-X-PLAYLIST-TYPE:VOD");
   content.AppendLine("#EXT-X-INDEPENDENT-SEGMENTS");

   for (double index = 0; (index * interval) < duration; index++)
   {
      content.AppendLine(String.Format("#EXTINF:{0:#.000000},", ((duration - (index * interval)) > interval) ? interval : ((duration - (index * interval)))));
      content.AppendLine(String.Format("{0:00000}.ts", index));
   }

   content.AppendLine("#EXT-X-ENDLIST");

   return content.ToString();
}

[HttpGet]
[Route("stream/{id}/{resolution}.m3u8")]
public IActionResult Stream(string id, string resolution)
{
   double duration = RetrieveVideoLengthInSeconds();
   return Content(GenerateVideoOnDemandPlaylist(duration, 10), "application/x-mpegURL", Encoding.UTF8);
}


  


  Here's an example of how the .m3u8 file looks like :

  


  #EXTM3U
#EXT-X-VERSION:6
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-INDEPENDENT-SEGMENTS
#EXTINF:10.000000,
00000.ts
#EXTINF:3.386667,
00001.ts
#EXT-X-ENDLIST


  


  So the player would ask for 00000.ts, 00001.ts, etc. and the next step is to have them generated on demand :

  


  public byte[] GenerateVideoOnDemandSegment(int index, int duration, string path)&#xA;{&#xA;   int timeout = 30000;&#xA;   int totalWaitTime = 0;&#xA;   int waitInterval = 100;&#xA;   byte[] output = Array.Empty<byte>();&#xA;   string executable = "/opt/homebrew/bin/ffmpeg";&#xA;   DirectoryInfo temp = Directory.CreateDirectory(System.IO.Path.Combine(System.IO.Path.GetTempPath(), System.IO.Path.GetRandomFileName()));&#xA;   string format = System.IO.Path.Combine(temp.FullName, "output-%05d.ts");&#xA;&#xA;   using (Process ffmpeg = new())&#xA;   {&#xA;      ffmpeg.StartInfo.FileName = executable;&#xA;&#xA;      ffmpeg.StartInfo.Arguments = String.Format("-ss {0} ", index * duration);&#xA;      ffmpeg.StartInfo.Arguments &#x2B;= String.Format("-y -t {0} ", duration);&#xA;      ffmpeg.StartInfo.Arguments &#x2B;= String.Format("-i \"{0}\" ", path);&#xA;      ffmpeg.StartInfo.Arguments &#x2B;= String.Format("-c:v libx264 -c:a aac ");&#xA;      ffmpeg.StartInfo.Arguments &#x2B;= String.Format("-segment_time {0} -reset_timestamps 1 -break_non_keyframes 1 -map 0 ", duration);&#xA;      ffmpeg.StartInfo.Arguments &#x2B;= String.Format("-initial_offset {0} ", index * duration);&#xA;      ffmpeg.StartInfo.Arguments &#x2B;= String.Format("-f segment -segment_format mpegts {0}", format);&#xA;&#xA;      ffmpeg.StartInfo.CreateNoWindow = true;&#xA;      ffmpeg.StartInfo.UseShellExecute = false;&#xA;      ffmpeg.StartInfo.RedirectStandardError = false;&#xA;      ffmpeg.StartInfo.RedirectStandardOutput = false;&#xA;&#xA;      ffmpeg.Start();&#xA;&#xA;      do&#xA;      {&#xA;         Thread.Sleep(waitInterval);&#xA;         totalWaitTime &#x2B;= waitInterval;&#xA;      }&#xA;      while ((!ffmpeg.HasExited) &amp;&amp; (totalWaitTime &lt; timeout));&#xA;&#xA;      if (ffmpeg.HasExited)&#xA;      {&#xA;         string filename = System.IO.Path.Combine(temp.FullName, "output-00000.ts");&#xA;&#xA;         if (!File.Exists(filename))&#xA;         {&#xA;            throw new FileNotFoundException("Unable to find the generated segment: " &#x2B; filename);&#xA;         }&#xA;&#xA;         output = File.ReadAllBytes(filename);&#xA;      }&#xA;      else&#xA;      {&#xA;         // It&#x27;s been too long. Kill it!&#xA;         ffmpeg.Kill();&#xA;      }&#xA;   }&#xA;&#xA;   // Remove the temporary directory and all its contents.&#xA;   temp.Delete(true);&#xA;&#xA;   return output;&#xA;}&#xA;&#xA;[HttpGet]&#xA;[Route("stream/{id}/{index}.ts")]&#xA;public IActionResult Segment(string id, int index)&#xA;{&#xA;   string path = RetrieveVideoPath(id);&#xA;   return File(GenerateVideoOnDemandSegment(index, 10, path), "application/x-mpegURL", true);&#xA;}&#xA;</byte>

  


  So as you can see, here's the command I use to generate each segment incrementing -ss and -initial_offset by 10 for each segment :

  


  ffmpeg -ss 0 -y -t 10 -i "video.mov" -c:v libx264 -c:a aac -segment_time 10 -reset_timestamps 1 -break_non_keyframes 1 -map 0 -initial_offset 0 -f segment -segment_format mpegts /var/folders/8h/3xdhhky96b5bk2w2br6bt8n00000gn/T/4ynrwu0q.z24/output-%05d.ts


  


  The Problem

  


  Things work on a functional level, however the transition between segments is slightly glitchy and especially the audio has very short interruptions at each 10 second mark. How can I ensure the segments are seamless ? What can I improve in this process ?

  


• How can I make a GStreamer pipeline to read individual frames and publish stream ?

  30 janvier 2024, par Alvan Rahimli

  I have an external system which sends individual H264 encoded frames one by one via socket. What I'm trying to do is getting these frames and publishing an RTSP stream to RTSP server that I have.

  


  After getting frames (which is just reading TCP socket in chunks) my current approach is like this :

  


  I read frames, then start a process with following command, and then write every frame to STDIN of the process.

  


  gst-launch-1.0 -e fdsrc fd=0 ! 
                  h264parse ! 
                  avdec_h264 ! 
                  videoconvert ! 
                  videorate ! 
                  video/x-raw,framerate=25/1 ! 
                  avimux ! 
                  filesink location=gsvideo3.avi


  


  I know that it writes stream to AVI file, but this is closest I was able to get to a normal video. And it is probably very inefficient and full of redundant pipeline steps.

  


  I am also open to FFMPEG commands, but GStreamer is preferred as I will be able to embed it to my C# project via bindings and keep stuff in-process.

  


  Any help is appreciated, thanks in advance !