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• memory leak reading video frames to numpy array using ffmpeg as a python subprocess

  19 novembre 2023, par paddyg

  I can stream videos frame by frame to an OpenGL Texture2D OK in python (pi3d module, example in pi3d_demos/VideoWalk.py) but I've noticed that it gradually leaks memory. Below is a stripped down version of the code that shows the problem.

  


  Can anyone see where I'm leaking ? The memory seems to be recovered when python stops. I've tried explicitly setting things to None or calling the garbage collector manually.

  


  #!/usr/bin/python
import os
import numpy as np
import subprocess
import threading
import time
import json

def get_dimensions(video_path):
    probe_cmd = f'ffprobe -v error -show_entries stream=width,height,avg_frame_rate -of json "{video_path}"'
    probe_result = subprocess.check_output(probe_cmd, shell=True, text=True)
    video_info_list = [vinfo for vinfo in json.loads(probe_result)['streams'] if 'width' in vinfo]
    if len(video_info_list) > 0:
        video_info = video_info_list[0] # use first if more than one!
        return(video_info['width'], video_info['height'])
    else:
        return None

class VideoStreamer:
    def __init__(self, video_path):
        self.flag = False # use to signal new texture
        self.kill_thread = False
        self.command = [ 'ffmpeg', '-i', video_path, '-f', 'image2pipe',
                        '-pix_fmt', 'rgb24', '-vcodec', 'rawvideo', '-']
        dimensions = get_dimensions(video_path)
        if dimensions is not None:
            (self.W, self.H) = dimensions
            self.P = 3
            self.image = np.zeros((self.H, self.W, self.P), dtype='uint8')
            self.t = threading.Thread(target=self.pipe_thread)
            self.t.start()
        else: # couldn't get dimensions for some reason - assume not able to read video
            self.W = 240
            self.H = 180
            self.P = 3
            self.image = np.zeros((self.H, self.W, self.P), dtype='uint8')
            self.t = None

    def pipe_thread(self):
        pipe = None
        while not self.kill_thread:
            st_tm = time.time()
            if pipe is None:
                pipe = subprocess.Popen(self.command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, bufsize=-1)
            self.image = np.frombuffer(pipe.stdout.read(self.H * self.W * self.P), dtype='uint8') # overwrite array
            pipe.stdout.flush() # presumably nothing else has arrived since read()
            pipe.stderr.flush() # ffmpeg sends commentary to stderr
            if len(self.image) < self.H * self.W * self.P: # end of video, reload
                pipe.terminate()
                pipe = None
            else:
                self.image.shape = (self.H, self.W, self.P)
                self.flag = True
            step = time.time() - st_tm
            time.sleep(max(0.04 - step, 0.0)) # adding fps info to ffmpeg doesn't seem to have any effect
        if pipe is not None:
            pipe.terminate()
            pipe = None

    def kill(self):
        self.kill_thread = True
        if self.t is not None:
            self.t.join()

vs = None
try:
    while True:
        for (path, _, videos) in os.walk("/home/patrick/Pictures/videos"):
            for video in videos:
                print(video)
                os.system("free") # shows gradually declining memory available
                vs = VideoStreamer(os.path.join(path, video))
                for i in range(500):
                    tries = 0
                    while not vs.flag and tries < 5:
                        time.sleep(0.001)
                        tries += 1
                    # at this point vs.image is a numpy array HxWxP bytes
                    vs.flag = False
                vs.kill()
except KeyboardInterrupt:
    if vs is not None:
        vs.kill()


os.system("free")


  


• colored TV-Noise with windows

  8 janvier 2024, par LookAndSee

  I have some question to the colored noise at image 2 of the following thread :

  


  Simulating TV noise

  


  

  • how can i get this in windows ? I like a random pattern consisting of red, green, blue, white and black points, like 255:0:0, 0:255:0, 0:0:255, 255:255:0, 0:0:0 and 255:255:255 - no pink, no orange, no cyan ... at the first step.

  


  


  but random in all 3 places always delievers (with ceil, floor or round) whole black, or whole white or bw-noise :-(
does it mean, the random(1) per point is 3 times the same in one computing-cycle ?

  


  Any suggestion ?

  


  This is what i tried :

  


  ffmpeg -y -f lavfi -i nullsrc=s=1280x720 -filter_complex "geq=r=(round(random(1)))*255:g=(round(random(1)))*255:b=(round(random(1)))*255;aevalsrc=-2+random(0)" -t 5 output.mkv


  


• Can I only use video file to countdown at last frame ? [closed]

  5 mai 2024, par mikezang

  I save the last frame to image when I create a video, then I convert image to 10 seconds video and put countdown on it, at last, merge this two videos. I can also use video to countdown but that start from first frame, how can I countdown at last frame ?

  


  countdown.bat

  


  ffmpeg -hide_banner ^
    -i "C:\myvideos\video.mp4" ^
    -filter_complex_script countdown.txt ^
    -t 30 -y %2.mp4


  


  countdown.txt

  


  [0:v]scale=864:504:force_original_aspect_ratio=decrease,pad=864:504:-1:-1,setsar=1[s0];
[s0]drawtext=fontfile='/WINDOWS/Fonts/Arial.ttf':text='%{eif\:10-t\:d}':
box=1:boxborderw=10:boxcolor=orange@0.4:
fontsize=24:x=w-tw-10:y=10:fontcolor=red:enable='between(t,0,10)';