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• CPU usage and memory of Gstreamer pipleline

  10 mars 2013, par Myles Megyesi

  I'm using gstreamer to capture video from a webcam, encode it with x264 and stream it using a gstrtpbin. It works great. However, it uses about 50% of all four of my cores and a lot of memory. Is there anything I can do to lower the CPU and memory usage ? Here's the pipeline.

  pipeline_description = "gstrtpbin latency=0 max-latency=100 drop-on-latency=true use-pipeline-clock=true ntp-sync=true name=rtpbin " \
  
          "autovideosrc ! video/x-raw-yuv,width=640,height=480,framerate=30/1 ! " \
  
          "tee name=t_vid ! queue ! fpsdisplaysink name=fpssink text-overlay=false video-sink=xvimagesink signal-fps-measurements=true t_vid. ! " \
  
          "queue ! videorate ! ffmpegcolorspace ! x264enc pass=qual tune=zerolatency quantizer=40 ! queue ! rtph264pay ! rtpbin.send_rtp_sink_0 " \
  
          "rtpbin.send_rtp_src_0 ! udpsink port=%d host=%s sync=false async=false rtpbin.send_rtcp_src_0 ! " \
  
          "udpsink port=%d host=%s sync=false async=false name=vrtcpsink udpsrc port=%d ! " \
  
          "rtpbin.recv_rtcp_sink_0 autoaudiosrc ! queue ! audioresample ! audioconvert ! alawenc ! rtppcmapay ! rtpbin.send_rtp_sink_1 " \
  
          "rtpbin.send_rtp_src_1 ! udpsink port=%d host=%s sync=false async=false rtpbin.send_rtcp_src_1 ! " \
  
          "udpsink port=%d host=%s sync=false async=false udpsrc port=%d ! rtpbin.recv_rtcp_sink_1" % (VRTP_SEND_PORT, DEST,
  
          VRTCP_SEND_PORT, DEST, VRTCP_RECV_PORT, ARTP_SEND_PORT, DEST, ARTCP_SEND_PORT, DEST, ARTCP_RECV_PORT)

• Extract 5th frame of video & merge into a video using ffmpeg C#

  6 juillet 2022, par mobile devteam

  I am trying to extract every 5th frame of a video and try to merge it in another video using ffmpeg.

  


  So far, I have tried 2 separate commands & processes :

  


  

  1. For extracting every 5th frame & storing it in a folder.

  


  


  
             

string argumentStrFinal = "-i {0} -vf \"select = not(mod(n\\, 5))\" -vsync vfr {1}/img_%03d.jpg";
                argumentStrFinal = String.Format(argumentStrFinal, inputPath, filePath);
                ProcessStartInfo startInfo5 = new ProcessStartInfo()
                {
                    FileName = ffmpegPath,
                    Arguments = argumentStrFinal,
                    UseShellExecute = false,
                    CreateNoWindow = true
                    //RedirectStandardError = true,
                };

                string outputPathFps = Path.Combine(filePath, "outputtemp_" + DateTime.UtcNow.Ticks + ".avi");
                Process exeProcess5 = Process.Start(startInfo5);

                exeProcess5.WaitForExit();



  


  2.For creating the video from the folder of frame images

  


    string argumentStrFinalMerge = "-framerate {2} -i {0}\\img_%03d.jpg {1}";
                    argumentStrFinalMerge = String.Format(argumentStrFinalMerge, filePath, outputPath, standardFrameRate);
                    
                    ProcessStartInfo startInfo6 = new ProcessStartInfo()
                    {
                        FileName = ffmpegPath,
                        Arguments = argumentStrFinalMerge,
                        UseShellExecute = false,
                        CreateNoWindow = true
                        //RedirectStandardError = true,
                    };

                    Process exeProcess6 = Process.Start(startInfo6);


  


  The problem is the two different processes are taking longer time so I want to merge this commands in single process.

  


  Please suggest me a way to do it.

  


• How to get webam frames one by one but also compressed ?

  29 mars, par Vorac

  I need to grab frames from the webcam of a laptop, transmit them one by one and the receiving side stitch them into a video. I picked ffmpeg-python as wrapper of choice and the example from the docs works right away :

  


  #!/usr/bin/env python

# In this file: reading frames one by one from the webcam.


import ffmpeg

width = 640
height = 480


reader = (
    ffmpeg
    .input('/dev/video0', s='{}x{}'.format(width, height))
    .output('pipe:', format='rawvideo', pix_fmt='yuv420p')
    .run_async(pipe_stdout=True)
)

# This is here only to test the reader.
writer = (
    ffmpeg
    .input('pipe:', format='rawvideo', pix_fmt='yuv420p', s='{}x{}'.format(width, height))
    .output('/tmp/test.mp4', format='h264', pix_fmt='yuv420p')
    .overwrite_output()
    .run_async(pipe_stdin=True)
)


while True:
    chunk = reader.stdout.read(width * height * 1.5)  # yuv
    print(len(chunk))
    writer.stdin.write(chunk)


  


  Now for the compression part.

  


  My reading of the docs is that the input to the reader perhaps needs be rawvideo but nothing else does. I tried replacing rawvideo with h264 in my code but that resulted in empty frames. I'm considering a third invocation looking like this but is that really the correct approach ?

  


  encoder = (                                                                     
    ffmpeg                                                                      
    .input('pipe:', format='rawvideo', pix_fmt='yuv420p', s='{}x{}'.format(width, height))
    .output('pipe:', format='h264', pix_fmt='yuv420p')                          
    .run_async(pipe_stdin=True, pipe_stdout=True)