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• Scaling nginx-rtmp livestreaming with ffmpeg transcoding

  31 mars 2020, par hoodsy

  I currently have a functional livestreaming setup using the prolific nginx-rtmp library, and I’m using ffmpeg to provide various resolutions of my stream.

  The only problem is, ffmpeg with only 2 outputs eats up 50% of my CPU. I’d like to be able to support up to 20 streamers at once – with the current demand, that would mean I need 10x the CPU power that I currently have !

  How can I scale my transcoding setup with nginx-rtmp and ffmpeg ?

  rtmp {
  
  server {
  
      listen 1935;
  
  
  
      application src {
  
          live on;
  
          exec_push ffmpeg -i rtmp://localhost/src/$name
  
              -c:v copy -preset:v ultrafast -b:v 512K -c:a copy -tune zerolatency -f flv rtmp://localhost/hls/$name_hi
  
              -c:v libx264 -preset:v ultrafast -s 852x480 -b:v 128K -c:a copy -tune zerolatency -f flv rtmp://localhost/hls/$name_low;
  
  
  
              # -c:v libx264 -s 852x480 -b:v 128K -c:a copy -tune zerolatency -f flv rtmp://localhost/hls/$name_low;
  
              # -c:v libx264 -s 1280x720 -b:v 256k -c:a copy -tune zerolatency -f flv rtmp://localhost/hls/$name_mid;
  
      }
  
  
  
      application hls {
  
          live on;
  
          hls on;
  
          hls_path /tmp/hls;
  
  
  
          # hls_fragment 1s;
  
          # hls_playlist_length 4s;
  
          hls_fragment 4s;
  
          hls_playlist_length 12s;
  
          hls_nested on;
  
          hls_variant _low BANDWIDTH=160000;
  
          # hls_variant _mid BANDWIDTH=320000;
  
          hls_variant _hi  BANDWIDTH=640000;
  
      }
  
  }

  }

• Repair mpeg files using ffmpeg

  17 août 2018, par rsdrsd

  I have a bunch of MPEG files which are somehow invalid or incorrect. I can play the files in different media players but when I upload the files and they should automatically be converted. It takes a very long time to create screenshots and it creates about 10000 screenshots instead of the 50 to be expected. The command is part of an automatic conversion app. With mp4 and other files it works great but whit MPEG it doesn’t work as expected. The creation of screenshots eats up all memory and processor power.

  For creating screenshots I have tried the following :

  ffmpeg -y -i /input/file.mpeg -f image2 -aspect 16:9 -bt 20M -vsync passthrough -vf select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)' /output/file-%05d.jpg

  this just creates 2 screenshots while I expect 50 or so. The following command :

  ffmpeg -y -i /input/file.mpeg -f image2 -vf fps=fps=1/10 -aspect 16:9 -vsync passthrough -bt 20M /output/file-%05d.jpg

  gave me errors about buffers :

      ffmpeg version N-39361-g1524b0f Copyright (c) 2000-2014 the FFmpeg developers
  
        built on Feb 26 2014 23:46:40 with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-4)
  
        configuration: --prefix=/home/example/ffmpeg_build --extra-cflags=-I/home/example/ffmpeg_build/include --extra-ldflags=-L/home/example/ffmpeg_build/lib --bindir=/home/example/bin --extra-libs=-ldl --enable-gpl --enable-nonfree --enable-libfdk_aac --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libfreetype --enable-libspeex --enable-libtheora
  
        libavutil      52. 66.100 / 52. 66.100
  
        libavcodec     55. 52.102 / 55. 52.102
  
        libavformat    55. 33.100 / 55. 33.100
  
        libavdevice    55. 10.100 / 55. 10.100
  
        libavfilter     4.  2.100 /  4.  2.100
  
        libswscale      2.  5.101 /  2.  5.101
  
        libswresample   0. 18.100 /  0. 18.100
  
        libpostproc    52.  3.100 / 52.  3.100
  
      [mp3 @ 0x200d7c0] Header missing
  
      [mpegts @ 0x2008a60] DTS discontinuity in stream 0: packet 6 with DTS 34185, packet 7 with DTS 8589926735
  
      [mpegts @ 0x2008a60] Invalid timestamps stream=0, pts=7157, dts=8589932741, size=150851
  
      Input #0, mpegts, from '/home/example/app/uploads/21.mpeg':
  
        Duration: 00:03:14.75, start: 0.213000, bitrate: 26112 kb/s
  
        Program 1
  
  Stream #0:0[0x3e9]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv), 1440x1080 [SAR 4:3 DAR 16:9], max. 25000 kb/s, 29.97 fps, 60 tbr, 90k tbn, 59.94 tbc
  
  Stream #0:1[0x3ea]: Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 384 kb/s
  
      [swscaler @ 0x1ff9860] deprecated pixel format used, make sure you did set range correctly
  
      Output #0, image2, to '/home/example/app/uploads/21-%05d.jpg':
  
        Metadata:
  
  encoder         : Lavf55.33.100
  
  Stream #0:0: Video: mjpeg, yuvj420p, 1440x1080 [SAR 4:3 DAR 16:9], q=2-31, 200 kb/s, 90k tbn, 0.10 tbc
  
      Stream mapping:
  
        Stream #0:0 -> #0:0 (mpeg2video -> mjpeg)
  
      Press [q] to stop, [?] for help
  
      [mpegts @ 0x2008a60] Invalid timestamps stream=0, pts=7157, dts=8589932741, size=150851
  
      [output stream 0:0 @ 0x1ff2ba0] 100 buffers queued in output stream 0:0, something may be wrong.
  
      [output stream 0:0 @ 0x1ff2ba0] 1000 buffers queued in output stream 0:0, something may be wrong.

  and it creates about 10000 screenshots while I expect 50.

  Now I have read somewhere on how to repair some broken files. For this I have the following command :

  ffmpeg -y -i input.mpeg -codec:v copy -codec:a copy output.mpeg

  This, however, creates a file somewhat smaller, but if I run the same command on the output again, I would expect that it creates the same file, but the following command

  ffmpeg -y -i output.mpeg -codec:v copy -codec:a copy output2.mpeg

  returns a file which is much smaller and runs for only a few seconds while the original was about 3 minutes.

  If I run the "repair" commands for a not broken MPEG then it results in a much smaller file the first time I run the command. With ffprobe I checked what changed but the only thing that changes is MPEG-TS to MPEG-PS.

  If I run the command over an mp4 file it results in exactly the same file as expected. Does someone have a clue of what is going wrong. It is boggling me now for about two days and I really have no clue. Or does someone have a good suggestion on how to extract screenshots every 10 seconds without creating too much screenshots and eating up all memory and processor power.

• Invalid data found when processing input on ffmpeg m4s to mp4 transfer

  1er mars 2020, par keith scott

  The result of the power shell window

  I saw a post on here about converting m4s to mp4 and I have followed the steps of concatenating all the files into another m4s file that I called all.m4s and when I use the command ffmpeg -i allm4s.m4s -c copy video.mp4. I made the combined m4s file by coding an exe to add all the m4s files that have the word video in them to the m4s file. Here is the source code written in c# if you compile the code then that is the code I have used to make the m4s

  using System;
  
  using System.Collections.Generic;
  
  using System.Linq;
  
  using System.Text;
  
  using System.Threading.Tasks;
  
  using System.IO;
  
  
  
  namespace files
  
  {
  
      class Program
  
      {
  
          static void Main(string[] args)
  
          {
  
              string dir = Directory.GetCurrentDirectory();
  
              string[] info = Directory.GetFiles(dir);
  
              Console.WriteLine(dir + "\\allm4s.m4s");
  
              Console.ReadKey();
  
              foreach (string name in info)
  
              {
  
                  if (Path.GetFileName(name).Contains(".m4s") && Path.GetFileName(name).Contains("video"))
  
                  {
  
                      using (Stream srcStream = File.OpenRead(name))
  
                      {
  
                          using (Stream destStream = File.OpenWrite(dir+"\\allm4s.m4s"))
  
                          {
  
                              srcStream.CopyTo(destStream);
  
                              Console.WriteLine(destStream+name);
  
                          }
  
                      }
  
                  }
  
              }
  
              Console.ReadKey();
  
          }
  
      }
  
  }

  I think if there is to be an issue it is to do with this allm4s.m4s file as the file size is about 1.5mb even though each segment m4s is about 750kb each and there are quite a lot.If anyone has a way of adding concatenating lots of files together through a program/application that would be useful.