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• libavcodec/avcodec.h file not found on macos-14 arm m1

  27 juillet 2024, par mikeProgrammer

  I am writing a program that links to the ffmpeg dev libs and everything works correctly on ubuntu-22-x86-64 ubuntu-24-x86-64 macos-13-x86-64 but not on macos-14-arm-m1.

  


  I install ffmpeg with brew install ffmpeg and then I run this command :

  


  cc -fPIC -I/opt/homebrew/Cellar/erlang/26.2.5/lib/erlang/erts-14.2.5/include -Ic_src/xav -shared  -undefined dynamic_lookup c_src/xav/xav_nif.c c_src/xav/reader.c c_src/xav/decoder.c c_src/xav/utils.c -o /Users/runner/work/xav/xav/_build/test/lib/xav/priv/libxav.so -lavcodec -lswscale -lavutil -lavformat -lavdevice -lswresample


  


  which results in

  


  In file included from c_src/xav/xav_nif.c:1:&#xA;c_src/xav/decoder.h:1:10: fatal error: &#x27;libavcodec/avcodec.h&#x27; file not found&#xA;#include <libavcodec></libavcodec>avcodec.h>&#xA;         ^~~~~~~~~~~~~~~~~~~~~~&#xA;1 error generated.&#xA;In file included from c_src/xav/reader.c:1:&#xA;c_src/xav/reader.h:1:10: fatal error: &#x27;libavcodec/avcodec.h&#x27; file not found&#xA;#include <libavcodec></libavcodec>avcodec.h>&#xA;         ^~~~~~~~~~~~~~~~~~~~~~&#xA;1 error generated.&#xA;In file included from c_src/xav/decoder.c:1:&#xA;c_src/xav/decoder.h:1:10: fatal error: &#x27;libavcodec/avcodec.h&#x27; file not found&#xA;#include <libavcodec></libavcodec>avcodec.h>&#xA;         ^~~~~~~~~~~~~~~~~~~~~~&#xA;1 error generated.&#xA;In file included from c_src/xav/utils.c:1:&#xA;c_src/xav/utils.h:2:10: fatal error: &#x27;libavcodec/avcodec.h&#x27; file not found&#xA;#include <libavcodec></libavcodec>avcodec.h>&#xA;         ^~~~~~~~~~~~~~~~~~~~~~&#xA;

  


  When I locate header files and dynamic libs and set C_INCLUDE_PATH, LD_LIBRARY_PATH etc., the compilation works but I assume that this shouldn't be needed, should it ?

  


  My understanding is that, if I install ffmpeg using some package manager, ffmpeg header files and .dylib or .so should be automatically searchable (as long as there is no bug in package manager's install script). Is that correct ?

  


  The same commands work on macos-13-intel-x86-64

  


• ffmpeg-python extracting frames from camera in batches

  28 juin 2021, par Alter

  When I read frames from my camera using ffmpeg-python, the frames appear to come in batches of 4- why is this, and how can I change it ?

  


  I would like to get one frame at a time... I'm also hoping to avoid faking the frame times using the -r option

  


  

  


  In the image above, I'm recording at 30fps. The 120ms pause followed by 3 quick frames suggests that the frames are coming in batches of 4.

  


  Partial code

  


  reader = (ffmpeg
    .input('/dev/video0', framerate=fps)
    .output('pipe:', format='rawvideo', pix_fmt='rgb24')
    .run_async(pipe_stdout=True))
    
while True:
    start = time.time_ns()
    frame = reader.stdout.read(width * height * 3)
    logger.debug(f'frame read time: {(time.time_ns() - start)/1e6}ms')
    # Do something else
    logger.debug(f'frame capture loop: {(time.time_ns() - start)/1e6}ms')


  


• 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