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• compile own ffmpeg filter

  20 juin 2023, par lfk

  I'm trying compile my own ffmpeg filter using official tutorial. My filter uses C++ code. I made header file and adapted my C++ function definition for C. Now I'm trying compile with command make -j<libavfilter> ffmpeg</libavfilter>, but receiving an error message

  


  


  gcc -Llibavcodec -Llibavdevice -Llibavfilter -Llibavformat
-Llibavresample -Llibavutil -Llibpostproc -Llibswscale -Llibswresample -Wl,—as-needed -Wl,-z,noexecstack -Wl,—warn-common -Wl,-rpath-link=libpostproc:libswresample:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil:libavresample
-o ffmpeg_g fftools/ffmpeg_opt.o fftools/ffmpeg_filter.o fftools/ffmpeg_hw.o fftools/cmdutils.o fftools/ffmpeg.o -lavdevice
-lavfilter -lavformat -lavcodec -lswresample -lswscale -lavutil -lm -pthread -lm -lm -lz -pthread -lm -lz -lm -lm -pthread -lm libavfilter/libavfilter.a(vf_foobar.o) : In function `filter_frame' :
/home/joeyes/ffmpeg_sources/ffmpeg/libavfilter/vf_foobar.c:302 :
undefined reference to MyFunction.c
collect2 : ld returned 1 exit status
*** [ffmpeg_g] Error 1

  


  


  For compilation I added OBJS-$(CONFIG_FOOBAR_FILTER) += vf_foobar.o MyCode.o to /libavfilter/makefile

  


  Also I put MyCode.h & MyCode.cpp to /libavfilter folder

  


• Xamarin Mac FFmpeg launch path not accessible

  25 mars 2024, par Tecnopresley

  I have a Xamarin Forms project with Mac support and I am trying to implement FFmpeg, so I have downloaded the Static build from its official page and added it as in the resources folder of the Mac project with the build action in Content, then I have created a service that will basically remove the audio from a video that I indicate in a path with a FFmpeg command, to do the service I have based on the following answer and I have adapted it to C # :
https://stackoverflow.com/a/37422688/8496520

  


  The problem is that when I try to execute the command I get the following error :

  


  "NSInvalidArgumentException: launch path not accessible"


  


  And I can't find out why this happens, I use the following code in the service (The error occurs when calling the Launch () method of the NSTask) :

  


  public void ExecuteFFmpeg()
{
    try
    {
        var launchPath = NSBundle.MainBundle.PathForResource("ffmpeg", ofType: "");
        var compressTask = new NSTask();
        compressTask.LaunchPath = launchPath;
        compressTask.Arguments = new string[] {
            "-i",
            "downloads/test.mp4",
            "-c",
            "copy",
            "-an",
            "nosound.mp4" };
        compressTask.StandardInput = NSFileHandle.FromNullDevice();
        compressTask.Launch();
        compressTask.WaitUntilExit();
    }
    catch (Exception ex)
    {

    }


  


• Gstreamer video increases latency with decreased FPS

  19 novembre 2024, par Ri Di

  I am using RPI 5 to stream the video :

  


  rpicam-vid -t 0 --camera 0 --nopreview --mode 2304:1296:10:P --codec yuv420 
           --width 640 --height 360 --framerate 10 --rotation 0 
           --autofocus-mode manual --inline --listen -o - | 
     ffmpeg -f rawvideo -pix_fmt yuv420p -s:v 640x360 -r 10 -i /dev/stdin 
            -c:v libx264 -preset ultrafast -tune zerolatency -maxrate 300k 
            -bufsize 50k -g 30000 -f mpegts tcp://192.168.0.147:1234


  


  View it with :

  


  gst-launch-1.0 -v tcpserversrc host=0.0.0.0 port=1234 ! queue ! 
    tsdemux ! h264parse ! avdec_h264 ! videorate ! video/x-raw,framerate=10/1 !  
    videoconvert ! autovideosink sync=false


  


  Problem is that with 10 FPS I get around 2s of latency ! While 56 or 120 FPS results in below 300ms latency.

  


  Is the problem in sender or reader side ? Or both ?

  


  I am not planning to use the 10 FPS, its only for demonstration of problem. But I would like to get lower latency at 56 FPS - just like at 120 FPS (around 80-100 ms difference) or maybe even better, as it seems to get lower with higher FPS.

  


  Maybe there is some kind of buffering parameter which holds frames ?

  


  (of course, when testing with higher FPS I change both numbers in sender and the one in reader command. The camera is v3 RPI official)

  


  Also I'd like to mention that same thing happens with ffplay :

  


  ffplay -i -probesize 3000 tcp://0.0.0.0:1234/?listen