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• FFmpeg Muxing binary data with video into MPEG-TS stream

  22 avril 2020, par diogoaos

  I'm trying to create a MPEG-TS stream with FFmpeg. I feed FFmpeg video form a file and binary data from a UDP stream.

  



  ffmpeg -re -i video.mp4 \
       -f data -i udp://localhost:5000 \
       -map 0:0 -map 0:1 -map 1:0 -codec copy \
       -f mpegts test.ts


  



  I use socat to connect to FFmpeg and type random data :

  



  socat udp:localhost:5000 -


  



  When I try to demux the data channel (channel 2 is for data), it's empty :

  



  ffmpeg -i test.ts -map 0:2 -c:d copy -f data -


  



  I've also tried doing this feeding directly text files and that works fine (I can demux the data stream from the resulting .ts file and it's equal). I've also tried using named pipes connected to a Python script, but that didn't work well (FFmpeg seems to wait for an EOF and than does not keep reading the named pipe).

  



  How do I mux video and binary data from different sources into a single MPEG Transport Stream ?

  


• 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