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• Low latency routing of rtp input to rtsp output with ffmpeg on a server

  29 mai 2020, par guillefix

  I want to be able to do some simple low-latency screen share. I know peer-to-peer would be the lowest latency, but it seems using an intermediate server is a lot easier to setup. I have found this awesome little library, which sets up an RTSP server, which I'm running on my digital ocean server. I then :

  



  

  1. Set up OBS to stream using RTP to the server on port 8558 with libx264 encoding.

  


  2. Run ffmpeg -re -stream_loop -1 -i rtp://127.0.0.1:8558 -c:v libx264 -c:a aac -f rtsp rtsp://localhost:8554/mystream on the server.

  


  3. Open rtsp://<server ip="ip">:8554/mystream</server> on VLC.

  


  



  However, the latency seems to be quite high. With my crappy internet it must have been like half a minute. A friend with better internet saw it fluctuating between 4-15 seconds. Furthermore, there seems to be a lot of artifacts on the video (problems with encoding ? I'm not sure why these happen ?)

  



  I attach below my OBS settings, and an example of artifacts.

  



  My question is : is there some settings on OBS and on ffmpeg that would allow this to have as low end-to-end latency as possible, while not having too many bad artifacts ? I'm not very well versed on video encoding and streaming, so this is all quite new to me. I'm willing to learn !

  



  

  



  

  


• Is there any way that I can speed up the ffmpeg processing time

  20 mai 2020, par Ahmed Al-Rayan

  I am facing a problem with the processing process. I use a real joint server in a digital hosting package of $ 10 and use cloud service from Amazon s3. The problem is when uploading a video, whatever the size of the video, whether its size is 1 megabyte or 2 Giga. After the upload process, the processing process starts to upload, there is no problem But when the processing process takes a very long time so that I cannot complete it, what is the solution to that, is there a problem for me or is this process normal ?
 I use laravel-ffmpeg and through laravel queue I am cutting the video into several qualities I will attach the code to you below.

  



  public function handle()
{
    //180p
    $lowBitrate1 = (new X264('aac'))->setKiloBitrate(613);
    //270p
    $lowBitrate2 = (new X264('aac'))->setKiloBitrate(906);
    //360p
    $midBitrate1 = (new X264('aac'))->setKiloBitrate(1687);
    //540p
    $midBitrate2 = (new X264('aac'))->setKiloBitrate(2227);
    //720p
    $highBitrate1 = (new X264('aac'))->setKiloBitrate(4300);
    //1080
    $highBitrate2 = (new X264('aac'))->setKiloBitrate(7917);

FFMpeg::fromDisk('s3')
    ->open($this->movie->path)
    ->exportForHLS()
    ->onProgress(function ($percent) {
        $this->movie->update([
            'percent' => $percent
        ]);
    })
    ->setSegmentLength(10)// optional
    ->addFormat($lowBitrate1)
    ->addFormat($lowBitrate2)
    ->addFormat($midBitrate1)
    ->addFormat($midBitrate2)
    ->addFormat($highBitrate1)
    ->addFormat($highBitrate2)
    ->toDisk('s3')
    ->save("public/Movies/{$this->movie->id}/{$this->movie->id}.m3u8");
}//end of handle


  


• Video Feedback Loop with ffmpeg

  4 mai 2020, par driangle

  I am trying to create a digital video feedback loop between two computers.

  



  What I mean by this is the following :

  



  

  



  I attempted several combinations of protocols and video formats and I found out this is the closest I can get. The original video was an "mov" but I had to convert it to .ts in order to get this far, had other issues when using mov or mp4.

  



  I ran the commands in this order to make sure tcp listeners were up before the clients.

  



  On Local Computer

  



  # Command 1: Temporary attempt to capture output of loop
ffmpeg -i 'udp://0.0.0.0:6002?listen&overrun_nonfatal=1' -c copy out.ts


  



  # Command 2: Receives stream from remote host and forwards back to beginning of loop
ffmpeg -i tcp://0.0.0.0:6001?listen -f mpegts udp://localhost:6002


  



  On Remote Computer

  



  #  Command 3: Receives stream from local host and returns stream to another ffmpeg instance
ffmpeg -i tcp://0.0.0.0:6000?listen -f mpegts tcp://:6001


  



  On Local Computer

  



  # Command 4: Sends stream to remote host
ffmpeg -re -i in.ts  -f mpegts tcp://:6000


  



  The steps above don't quite complete the feedback loop, but they do result in a successful video out.ts

  



  Then I tried to modify Command 4 so that it could merge both a file and a udp stream, this is a naive attempt I know, I am not very good with ffmpeg.

  



   ffmpeg \
    -re -i in.ts -i udp://0.0.0.0:6002 \
    -filter_complex " \
        [0:v]setpts=PTS-STARTPTS, scale=540x960[top]; \
        [1:v]setpts=PTS-STARTPTS, scale=540x960, \
             format=yuva420p,colorchannelmixer=aa=0.5[bottom]; \
        [top][bottom]overlay=shortest=1" \
    -f mpegts tcp://:6000


  



  The result was that the command hung waiting for a data on the udp port, which makes sense in hindsight.

  



  I would like to know :

  



  

  • Can this be done at all ? If so, what do I need to change ?

  


  • Do I need to abandon ffmpeg for this task and look into something else ?

  


  



  If you're asking why would I do this, the answer is there is no good reason other than I am curious to know if it's possible and what results it would yield.