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• Reading video frame by frame using php, ffmpeg and proc_open

  29 avril 2020, par Tom

  I want to use proc_open to read every frame from a video using ffmpeg and then use PHP to do something with the frames.
Here's the example that does the opposite- it sends frame by frame from PHP to ffmpeg :

  



  $descriptors = array(
    0 => array("pipe", "r"),

    1 => array("pipe", "w"), 
    2 => array("file", "C:/error-output.txt", "a")  
);

$frames = glob('Q:/images/*.jpg');


$command = "ffmpeg -f image2pipe -pix_fmt rgb24 -framerate 10 -c:v mjpeg -i - ".
                "-r 10 -vcodec libx264 -pix_fmt yuv420p  -preset faster -crf 17 ".
                "-y test.mp4";

$ffmpeg = proc_open($command, $descriptors, $pipes);

if (!is_resource($ffmpeg))
{
    die('Could not run ffmpeg');

}

foreach ($frames AS $frame)
{

    fwrite($pipes[0], file_get_contents($frame) );
}

fclose($pipes[0]);


  



  And here's how I am trying but can't get it right :

  



  $descriptors = array(
    0 => array("pipe", "r"),

    1 => array("pipe", "w"),  write to
    2 => array("file", "C:/error-output.txt", "a") 
);


$command = "ffmpeg -i 1.gif -ss 00:00:3 -s 650x390 -vframes 100 -c:v png -f image2pipe -";

$ffmpeg = proc_open($command, $descriptors, $pipes);

if (!is_resource($ffmpeg))
{
    die('Could not run ffmpeg');

}

while (!feof($pipes[1]))
{
    $frame = fread($pipes[1], 5000);
}

fclose($pipes[1]);


  



  The biggest issue is I don't know how much data to read from ffmpeg to get a whole frame.

  


• FFmpeg video is very distorted after a pixel-perfect start

  7 septembre 2022, par AlvinfromDiaspar

  I am using the following FFMpeg command to convert a H.264 UDP streamed video from a Tello drone to another address.

  



  ffmpeg -i udp://0.0.0.0:11111 -preset ultrafast -vcodec libx264 -tune zerolatency -b 900k -f h264 udp://127.0.0.1:5000


  



  Then I simply use the following OpenCv to read from that new address :

  



  this.Capture = new OpenCvSharp.VideoCapture("udp://127.0.0.1:5000", OpenCvSharp.VideoCaptureAPIs.FFMPEG);


  



  From this Capture reference, i obtain the next frame by calling this.Capture.Read(mat).
When i assigned the convert image to the UI, the image is pixel perfect !

  



  However, after the initial rendering, i am not seeing immediate updates. But i do see very laggy video updates that is very distorted. It looks like each consecutive frame is just the delta/difference drawn on top of the previous frame.

  



  Is there anything i can tweak/modify in my FFMpeg command to resolve this distorted video rendering ?

  



  Update 1
I was able to make some progress. The video updates, still with distortion, but overall distortion is a bit less. And the frames update more responsively.

  



  To get to this point, i simply added this parameter to my FFMpeg command :

  



  -g 100


  



  I also tried :

  



  -g 300


  


• Using GStreamer to receive and send h264 video (from OBS)

  16 mars 2020, par Ivorius

  I’ve been trying to set up using GStreamer to get support for some input I can output from OBS.

  OBS : rtp_mpegts to udp ://localhost:5000

  http-launch 8080 webmmux streamable=true name=stream udpsrc uri=udp://localhost:5000 caps="application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)MP2T-ES, payload=(int)
  
  33" ! gstrtpjitterbuffer latency=200 ! application/x-rtp ! rtpmp2tdepay ! video/mpegts ! mpegtsdemux ! video/x-h264 ! queue ! decodebin ! vp8enc ! stream.   audiotestsrc ! vorbisenc ! stream.

  However, using this it seems to accept connections, but just closes them again after a while. Any clues on what I am doing wrong ? I am open to any format changes as long as they’re supported by OBS / ffmpeg.

  As a bonus, how do I add support for audio as well ?

  Background

  I’ve found https://github.com/sdroege/http-launch, which works well in displaying a GStreamer video over http:

  <video autoplay="autoplay" controls="">
  
      <source src="https://localhost:8080" type="video/mp4" codecs="avc1.4D401E, mp4a.40.2">
  
      You browser doesn't support element <code>video
  .
  
  
  
  
  

  I’ve managed to set up a pipeline where I can use a GStreamer source to pipe into a http-launch
  pipeline and display it on video :

  http-launch 8080 webmmux streamable=true name=stream udpsrc port=5000 caps = "application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, payload=(int)96" ! mpegtsdemu
  
  x ! h264parse ! TIViddec2 ! videoconvert ! vp8enc ! stream.   audiotestsrc ! vorbisenc ! stream.
  
  
  
  gst-launch-1.0 -v videotestsrc ! videoconvert ! x264enc tune=zerolatency bitrate=500 speed-preset=superfast ! rtph264pay ! udpsink host=127.0.0.1 port=5000

  However, I don’t think OBS supports rpt over UDP. It uses ffmpeg to send these packets, which can stream rtp_mpegts. I’ve found some code snippets which claim to support the format, and stitch together the above pipeline.