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• Play a video with ffmpeg and SDL2 on a Raspberry Pi 5

  18 février 2024, par aforino

  I want to create a python script that decodes a h264 1080p video and outputs it via SDL2 on a Raspberry Pi 5. The Raspberry Pi 5 is able to play a h264 1080p video without problem using VLC. Total CPU load with VLC is about 10%. However decoding with ffmpeg and outputting via SDL2 uses around 70% CPU load. Since I want to be able to switch seamlessly between two output videos I will need to decode two videos at the same time. Therefore 70% CPU load for one transcoded 1080p video is not acceptable. How can I make the code more efficient and why is VLC so much more efficient ?

  


  This is my current python script :

  


  import numpy as np
import ffmpeg  # ffmpeg-python
import sdl2.ext

in_file = ffmpeg.input('bbb1080_x264.mp4', re=None)

width = 1920
height = 1080

process1 = (
    in_file
    .output('pipe:', format='rawvideo', pix_fmt='bgra')
    .run_async(pipe_stdout=True)
)

sdl2.ext.init()
window = sdl2.ext.Window("Hello World!", size=(width, height))
window.show()
windowsurface = sdl2.SDL_GetWindowSurface(window.window)
windowArray = sdl2.ext.pixels3d(windowsurface.contents)

sdl2.ext.mouse.hide_cursor()

while True:
    in_bytes = process1.stdout.read(width * height * 4)

    if not in_bytes:
        break

    in_frame = (
        np
        .frombuffer(in_bytes, np.uint8)
        .reshape([height, width, 4])
        .transpose(1, 0, 2)
    )

    for event in sdl2.ext.get_events():
        if event.type == sdl2.SDL_QUIT:
            exit()

    windowArray[:] = in_frame
    window.refresh()

process1.wait()


  


  Also it is interesting to note that when I start VLC on a Raspberry Pi 5 this is the output on the terminal

  


  [00007fff78c1a550] avcodec decoder error: cannot start codec (h264_v4l2m2m)
Fontconfig warning: ignoring UTF-8: not a valid region tag
[00007fff68002d70] gles2 generic error: parent window not available
[00007fff68002d70] xcb generic error: window not available
[00007fff680013f0] mmal_xsplitter vout display: Try drm
[00007fff68002d70] drm_vout generic: <<< OpenDrmVout: Fmt=I420
[00007fff68002d70] drm_vout generic error: Failed to get xlease`


  


  It indicates that VLC is not using the h264_v4l2m2m hardware acceleration.

  


• ffmpeg - store desired output to python variable

  15 janvier 2024, par Chris P

  If i run : ffmpeg -list_devices true -f dshow -i dummy i get :

  


  ffmpeg version 2023-01-30-git-2d202985b7-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      57. 44.100 / 57. 44.100
  libavcodec     59. 59.100 / 59. 59.100
  libavformat    59. 36.100 / 59. 36.100
  libavdevice    59.  8.101 / 59.  8.101
  libavfilter     8. 56.100 /  8. 56.100
  libswscale      6.  8.112 /  6.  8.112
  libswresample   4.  9.100 /  4.  9.100
  libpostproc    56.  7.100 / 56.  7.100
[dshow @ 00000236357d0480] "HP True Vision HD Camera" (video)
[dshow @ 00000236357d0480]   Alternative name "@device_pnp_\\?\usb#vid_04f2&pid_b6ab&mi_00#6&763f234&2&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
[dshow @ 00000236357d0480] "Microphone Array (Intel® Smart Sound Technology for Digital Microphones)" (audio)
[dshow @ 00000236357d0480]   Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{E8824DE9-F848-47F1-BB2A-EB24E11050FC}"
dummy: Immediate exit requested


  


  From this output i want to store : "HP True Vision HD Camera" (first video output) in a python variable.

  


  Is this possible ?

  


  I am trying

  


  import subprocess
ffmpeg_command = ["ffmpeg", "-list_devices", "true","-f", "dshow", "-i", "dummy"]
pipe = subprocess.run(ffmpeg_command,stdout=subprocess.PIPE,stderr=subprocess.PIPE,bufsize=10**8)
output = pipe.stdout
lines = output.splitlines()
for line in lines:
    if line.startswith("[dshow @"):
        if "(video)" in line:
            camera_info = line.split("\"")[1]
            print(camera_info)


  


• Opencv Videocapture fails to read https url videos

  23 novembre 2020, par Purav Zumkhawala

  I want to read HTTPS URL videos in my Ubuntu system without downloading them. I can do this in windows OS but when I try to run the same code in Ubuntu using the same opencv VideoCapture method it fails to get any frames.

  



  Why is this so ?

  



  I have used same opencv version in both Ubuntu and Windows, can anyone guide me towards a workaround, a tutorial using which I can compile opencv and stream url videos or any other library that supports this functionality in Ubuntu ?

  



  I have tried almost everything but with no productive result which has led me to finally ask this as a question.

  



  opencv build information :

  OpenCV modules:
    To be built:                 calib3d core dnn features2d flann gapi highgui imgcodecs imgproc java_bindings_generator ml objdetect photo python3 python_bindings_generator stitching video videoio
    Disabled:                    world
    Disabled by dependency:      -
    Unavailable:                 java js python2 ts
    Applications:                -
    Documentation:               NO
    Non-free algorithms:         NO

  GUI: 
    QT:                          YES (ver 4.8.7 EDITION = OpenSource)
      QT OpenGL support:         NO
    GTK+:                        NO
    VTK support:                 NO

  Media I/O: 
    ZLib:                        /lib64/libz.so (ver 1.2.3)
    JPEG:                        /opt/libjpeg-turbo/lib64/libjpeg.a (ver 62)
    WEBP:                        build (ver encoder: 0x020e)
    PNG:                         build (ver 1.6.35)
    TIFF:                        build (ver 42 - 4.0.9)
    JPEG 2000:                   build (ver 1.900.1)
    OpenEXR:                     build (ver 1.7.1)
    HDR:                         YES
    SUNRASTER:                   YES
    PXM:                         YES
    PFM:                         YES

  Video I/O:
    DC1394:                      NO
    FFMPEG:                      YES
      avcodec:                   YES (ver 58.21.104)
      avformat:                  YES (ver 58.17.101)
      avutil:                    YES (ver 56.18.102)
      swscale:                   YES (ver 5.2.100)
      avresample:                NO
    GStreamer:                   NO
    v4l/v4l2:                    linux/videodev2.h

  Parallel framework:            pthreads

  Trace:                         YES (with Intel ITT)

  Other third-party libraries:
    Lapack:                      NO
    Eigen:                       NO
    Custom HAL:                  NO
    Protobuf:                    build (3.5.1)

  OpenCL:                        YES (no extra features)
    Include path:                /io/opencv/3rdparty/include/opencl/1.2
    Link libraries:              Dynamic load

  Python 3:
    Interpreter:                 /opt/python/cp36-cp36m/bin/python (ver 3.6.5)
    Libraries:                   libpython3.6m.a (ver 3.6.5)
    numpy:                       /opt/python/cp36-cp36m/lib/python3.6/site-packages/numpy/core/include (ver 1.11.3)
    packages path:               lib/python3.6/site-packages

  Python (for build):            /opt/python/cp36-cp36m/bin/python

  Java:                          
    ant:                         NO
    JNI:                         NO
    Java wrappers:               NO
    Java tests:                  NO

  Install to:                    /io/_skbuild/linux-x86_64-3.6/cmake-install