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• Revision 28933 : on bouge

  31 mai 2009, par ben.spip@… — Log

  on bouge

• Why doesn't the ffmpeg output display the stream in the browser ? [closed]

  10 mai 2024, par Tebyy

  Why is it that when I create a livestream in Python using ffmpeg, and then I open the browser and visit the page, the page keeps loading continuously, and in PyCharm logs, I see binary data ? There are no errors displayed, and the code seems correct to me. I even tried saving to a file for testing purposes, and when I play the video, everything works fine. Does anyone know what might be wrong here ?

  


  Code :

  


  def generate_frames():
    cap = cv2.VideoCapture(os.path.normpath(app_root_dir().joinpath("data/temp", "video-979257305707693982.mp4")))
    while cap.isOpened():
        ret, frame = cap.read()
        if not ret:
            break

        yield frame


@app.route('/video_feed')
def video_feed():
    ffmpeg_command = [
        'ffmpeg', '-f', 'rawvideo', '-pix_fmt', 'bgr24',
        '-s:v', '1920x1080', '-r', '60',
        '-i', '-', '-vf', 'setpts=2.5*PTS', # Video Speed
        '-c:v', 'libvpx-vp9', '-g', '60', '-keyint_min', '60',
        '-b:v', '6M', '-minrate', '4M', '-maxrate', '12M', '-bufsize', '8M',
        '-crf', '0', '-deadline', 'realtime', '-tune', 'psnr', '-quality', 'good',
        '-tile-columns', '6', '-threads', '8', '-lag-in-frames', '16',
        '-f', 'webm', '-'
    ]
    ffmpeg_process = subprocess.Popen(ffmpeg_command, stdin=subprocess.PIPE, stderr=subprocess.PIPE, bufsize=-1)
    frames_generator = generate_frames()
    for frame in frames_generator:
        ffmpeg_process.stdin.write(frame)
        ffmpeg_process.stdin.flush()

    ffmpeg_process.stdin.close()
    ffmpeg_process.wait()

    def generate_video_stream(process):
        startTime = time.time()
        buffer = []
        sentBurst = False
        for chunk in iter(lambda: process.stderr.read(4096), b''):
            buffer.append(chunk)

            # Minimum buffer time, 3 seconds
            if sentBurst is False and time.time() > startTime + 3 and len(buffer) > 0:
                sentBurst = True
                for i in range(0, len(buffer) - 2):
                    print("Send initial burst #", i)
                    yield buffer.pop(0)

            elif time.time() > startTime + 3 and len(buffer) > 0:
                yield buffer.pop(0)

            process.poll()
            if isinstance(process.returncode, int):
                if process.returncode > 0:
                    print('FFmpeg Error', process.returncode)

                break

    return Response(stream_with_context(generate_video_stream(ffmpeg_process)), mimetype='video/webm', content_type="video/webm; codecs=vp9", headers=Headers([("Connection", "close")]))



  


• avfilter/pthread : use slice threading from avutil

  12 juillet 2017, par Muhammad Faiz

  avfilter/pthread : use slice threading from avutil
  Benchmark (with 2 cpus) :
  
  ./ffmpeg -f rawvideo -s 1280x720 -t 1000 -i /dev/zero \
  
      -filter_threads $threads -vf transpose=clock -f null null
  
  threads=2 :
  
    old : 31.129s 31.446s 31.574s
  
    new : 29.602s 29.636s 29.656s
  
  threads=3 (nb_threads = nb_cpus + 1 is bad choice at this situation) :
  
    old : 40.132s 40.279s 40.279s
  
    new : 39.308s 39.570s 39.693s
  
  threads=4 :
  
    old : 31.306s 31.366s 31.654s
  
    new : 30.231s 30.360s 30.451s
  Signed-off-by : Muhammad Faiz <mfcc64@gmail.com>
  

  • [DH] libavfilter/pthread.c