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• MediaRecorder - FFMPEG - RTMP issue

  5 octobre 2017, par Bear10

  Currently I’m working on streaming Audio and Video from a video captured in Chrome 61.0.3163.100 with the MediaRecorder API.

  The backend is running on node and it spawns a child process which runs ffmpeg :

  ffmpeg -threads 4 -i udp://127.0.0.1:41234 -t 5400 -ar 44100
  
  -b:a 128k -c:v libx264 -c:a libfdk_aac -pix_fmt yuv420p -r 30 -g 60 -vb 2048k -preset slow -minrate 2000k -maxrate 4000k test.mp4

  On the client side I send the raw Blob from Chrome to the Node server via web socket :

   var mediaStream = new MediaStream([videoOutput.getVideoTracks()[0], audioOutput.getAudioTracks()[0]]),
  
              recorder = new MediaRecorder(mediaStream, {
  
                  mimeType: 'video/webm;codecs=vp8'
  
              });
  
  
  
          socket = io('http://localhost:' + port);
  
  
  
          recorder.addEventListener('dataavailable', function (evt) {
  
              socket.emit('video:data', evt.data);
  
          });

  And in Node we simply resend via udp to the ffmpeg process :

  let client = dgram.createSocket('udp4'),
  
  
  
  client.send(chunk, 0, chunk.length, 41234, '127.0.0.1', function (err, bytes) {
  
              if (err) {
  
                  throw err;
  
              }
  
          });

  The resulting mp4 is viewable on VLC without any issues, despite many of the following warnings showing up in the FFMPEG console :

  stderr: frame= 1751 fps= 31 q=17.0 size=   15997kB time=00:00:58.39 bitrate=2244.3kbits/s dup=449 drop=32 speed=1.03x
  
  stderr: [mp4 @ 0x7fefe6019000] Non-monotonous DTS in output stream 0:1; previous: 2573919, current: 2573792; changing to 2573920. This may result in incorrect timestamps in the output file.
  
  
  
  stderr: frame= 1767 fps= 31 q=17.0 size=   16166kB time=00:00:58.90 bitrate=2248.4kbits/s dup=452 drop=32 speed=1.03x
  
  stderr: [libmp3lame @ 0x7fefe7004c00] Queue input is backward in time
  
  
  
  stderr: [mp4 @ 0x7fefe6019000] Non-monotonous DTS in output stream 0:1; previous: 2614768, current: 2614686; changing to 2614769. This may result in incorrect timestamps in the output file.

  However when I try to re stream this specific video on Youtube or any other RTMP platform (ex : Facebook) the audio is choppy, the command I use :

  ffmpeg -i ./test.mp4 -f flv rtmp://a.rtmp.youtube.com/live2/MYAPIKEY

  On the other hand any other "good" video not made from the aforementioned process re streams just fine and I suspect it might be from the warnings I’m getting.

  As an added bit of information streaming directly from my PC with avfoundation to youtube also works fine, and writing from avfoundation to a file and then streaming to youtube also works ok.

  The goal is to stream from my browser to the node server and directly to the Youtube RTMP without the choppy audio issue.

  If someone knows how to get rid of the warning to ensure ffmpeg isn’t the issue or can point me in the direction to achieve the desired result that’d be great.

• Replicating C metadata example from ffmpeg in C# using ffmpeg-autogen - av_dict_get fails

  2 octobre 2017, par Adam Baxter

  I am trying to replicate https://ffmpeg.org/doxygen/3.0/doc_2examples_2metadata_8c_source.html in C# using the wrapper from https://github.com/Ruslan-B/FFmpeg.AutoGen

  I can open and read some properties of the file just fine, however tag is always null, even after the call to av_dict_get

  My code is as follows

  using System;
  
  using System.IO;
  
  using System.Reflection;
  
  using System.Runtime.InteropServices;
  
  using System.Text;
  
  using FFmpeg.AutoGen;
  
  
  
  namespace ffmpeg_test
  
  {
  
      class Program
  
      {
  
          static void Main(string[] args)
  
          {
  
              var currentPath = Path.GetDirectoryName(Assembly.GetEntryAssembly().Location);
  
              var libPath = Path.Combine(currentPath, "lib");
  
              SetDllDirectory(libPath);
  
              ffmpeg.av_register_all();
  
              ffmpeg.avcodec_register_all();
  
  
  
              DoRiskyThings();
  
  
  
          }
  
  
  
          private static unsafe void DoRiskyThings()
  
          {
  
              var pFormatContext = ffmpeg.avformat_alloc_context();
  
  
  
              if (ffmpeg.avformat_open_input(&pFormatContext, "01 - 999,999.opus", null, null) != 0)
  
                  throw new ApplicationException(@"Could not open file.");
  
  
  
              ffmpeg.avformat_find_stream_info(pFormatContext, null);
  
  
  
              AVStream* pStream = null;
  
              pStream = pFormatContext->streams[0];
  
              var codecContext = *pStream->codec;
  
  
  
              Console.WriteLine($"codec name: {ffmpeg.avcodec_get_name(codecContext.codec_id)}");
  
              Console.WriteLine($"number of streams: {pFormatContext->nb_streams}");
  
  
  
              //attempting to replicate https://ffmpeg.org/doxygen/3.0/doc_2examples_2metadata_8c_source.html
  
              AVDictionaryEntry* tag = null;
  
              tag = ffmpeg.av_dict_get(pFormatContext->metadata, "", null, 2);
  
              while (tag != null)
  
              {
  
                  tag = ffmpeg.av_dict_get(pFormatContext->metadata, "", tag, 2);
  
                  Console.WriteLine(Encoding.UTF8.GetString(tag->key,100));
  
                  //tag->key and //tag->value are byte pointers
  
              }
  
          }
  
  
  
          [DllImport("kernel32", SetLastError = true)]
  
          private static extern bool SetDllDirectory(string lpPathName);
  
      }
  
  }

• MediaSource through socket stops

  23 août 2017, par Paulo Galdo Sandoval

  i’m trying to stream a rtsp live stream through socket.io using ffmpeg (this works fine), but now i need to get that video from the socket and play it on a HTML5 video tag.

  To do this i’m using MediaSurce, getting small pieces of video through the socket and then appending it to the MediaSource

  This solution reproduces the video a few seconds o minutes and then suddenly stops
  and it doesn’t throw me any error on the Chrome console

      var socket = io();
  
  
  
      var ms = new MediaSource();
  
      var sourceBuffer;
  
      var queue = [];
  
      var video = document.getElementById("video");
  
      video.src = window.URL.createObjectURL(ms);
  
  
  
      socket.on('start', function (response) {
  
          console.log(response);
  
          socket.emit('streaming', $stateParams.id);
  
          ms.addEventListener('sourceopen', videoLoad, false);
  
          ms.addEventListener('sourceclose', videoClosed, false);
  
      });
  
  
  
  
  
      function videoLoad() {
  
          sourceBuffer = ms.addSourceBuffer('video/webm; codecs="vorbis,vp8"');
  
          sourceBuffer.addEventListener('update', function () {
  
              if (queue.length > 0 && !sourceBuffer.updating) {
  
                  console.log(queue.length);
  
                  sourceBuffer.appendBuffer(queue.shift());
  
              }
  
          });
  
  
  
          socket.on('data', function (response) {
  
              var bytes = new Uint8Array(response);
  
              var blob = new Blob(bytes);
  
              console.log(blob.size);
  
              if (sourceBuffer.updating || queue.length > 0) {
  
                  queue.push(bytes);
  
              } else {
  
                  sourceBuffer.appendBuffer(bytes);
  
              }
  
          });
  
      }
  
  
  
      function videoClosed(e) {
  
          console.log('mediaSource readyState: ' + this.readyState);
  
      }

  On my chrome://media-internals/ the video players log show me a couple of time this, and then the video stops

  video_buffering_state   BUFFERING_HAVE_ENOUGH