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• Is there a way to apply a curve bend in ffmpeg ?

  25 mars 2020, par stevendesu

  I have four cameras each feeding me a different portion of a basketball court. Due to the slight offset of the cameras physical locations and lens distortion around the edges of the camera, I cannot simply stitch the videos together without some kind of correction.

  I’ve looked into ffmpeg’s perspective filter, as well as the lenscorrection filter. In the former case it was only able to create a trapezoid, not the curved image I want. In the latter case using negative values to k1 and k2 seemed to be heading in the right direction, but it either disorted the top and bottom of the image to the point of being nonsensical noise, or it zoomed in to the image so much that I lost important details.

  For the sample picture below, ultimately I want the midcourt line (the blue vertical line on the right side) to be vertical, and I want the mess of wires on the white desk at the bottom to remain visible and identifiable.

  Given a video which looks like the following :

  

  I wish to produce something like the following :

  

  This image was made using the "Curve Bend" filter in GIMP, but I just eye-balled it - so it’s not perfect. Ideally once I get the exact parameters the midcourt line will be perfectly vertical

  When using the lenscorrection filter, no values for k1 and k2 seemed to get the effect I want :

  Negative k1, negative k2 :

  

  Negative k1, positive k2 :

  

  Positive k1, negative k2 :

  

  Positive k1, positive k2 :

  

  In general :

  • negative / negative distorted the image beyond recognition
  • negative / positive looked alright, but the midcourt line was off the screen and it wasn’t clear if any distortion had been applied
  • positive / negative looked the best, but while the top and bottom curved in the middle of the left and right actually bulged out, leaving the midcourt line distorted
  • positive / positive was the opposite of the desired effect

• Evolution #4271 (Nouveau) : valider_url_distante => pouvoir déclarer des domaines distants et pas ...

  21 janvier 2019, par - Equipement

  Bonjour,

  La fonction valider_url_distante permet de déclarer des hosts distants :
  

  <span class="CodeRay"><span class="local-variable">$known_hosts</span> = pipeline(<span class="string"><span class="delimiter">'</span><span class="content">declarer_hosts_distants</span><span class="delimiter">'</span></span>, <span class="local-variable">$known_hosts</span>);
  </span>
  Télécharger

  C’est très bien, mais avec plusieurs centaines de hosts à déclarer (dont la liste varie dans le temps), cela devient compliqué à gérer.

  Serait-il possible d’avoir, en plus, la possibilité de déclarer des domaines distants ?

  Une première piste serait de pouvoir déclarer .example.com dans le pipeline pour inclure tous les *.example.com au lieu des les énumérer un par un.

  Une seconde piste consisterait à s’inspirer de la function need_proxy (via une constante avec la même syntaxe que pour le http_noproxy) :

  // Pour mémoire code actuel à conserver ...
  

  <span class="CodeRay">    <span class="local-variable">$is_known_host</span> = <span class="predefined-constant">false</span>;
      <span class="keyword">foreach</span> (<span class="local-variable">$known_hosts</span> <span class="keyword">as</span> <span class="local-variable">$known_host</span>) {
          <span class="local-variable">$parse_known</span> = <span class="predefined">parse_url</span>(<span class="local-variable">$known_host</span>);
          <span class="keyword">if</span> (<span class="local-variable">$parse_known</span>
            <span class="keyword">and</span> <span class="predefined">strtolower</span>(<span class="local-variable">$parse_known</span>[<span class="string"><span class="delimiter">'</span><span class="content">host</span><span class="delimiter">'</span></span>]) === <span class="predefined">strtolower</span>(<span class="local-variable">$parsed_url</span>[<span class="string"><span class="delimiter">'</span><span class="content">host</span><span class="delimiter">'</span></span>])) {
              <span class="local-variable">$is_known_host</span> = <span class="predefined-constant">true</span>;
              <span class="keyword">break</span>;
          }
      }
  </span>
  Télécharger

  // ... que l’on pourrait faire suivre de ce code (complètement inspiré de function need_proxy) :
  

  <span class="CodeRay">    <span class="keyword">if</span> (!<span class="local-variable">$is_known_host</span>) {
                  <span class="local-variable">$known_domaines</span> = _DECLARER_DOMAINES_DISTANTS;
   
                  <span class="local-variable">$known_domaines</span> = <span class="predefined">str_replace</span>(<span class="string"><span class="delimiter">"</span><span class="char">\n</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content"> </span><span class="delimiter">"</span></span>, <span class="local-variable">$known_domaines</span>);
                  <span class="local-variable">$known_domaines</span> = <span class="predefined">str_replace</span>(<span class="string"><span class="delimiter">"</span><span class="char">\r</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content"> </span><span class="delimiter">"</span></span>, <span class="local-variable">$known_domaines</span>);
                  <span class="local-variable">$known_domaines</span> = <span class="string"><span class="delimiter">"</span><span class="content"> </span><span class="local-variable">$known_domaines</span><span class="content"> </span><span class="delimiter">"</span></span>;
                  <span class="local-variable">$domain</span> = <span class="predefined">strtolower</span>(<span class="local-variable">$parsed_url</span>[<span class="string"><span class="delimiter">'</span><span class="content">host</span><span class="delimiter">'</span></span>]);
   
                  <span class="keyword">if</span> (<span class="predefined">strpos</span>(<span class="local-variable">$known_domaines</span>, <span class="string"><span class="delimiter">"</span><span class="content"> </span><span class="local-variable">$domain</span><span class="content"> </span><span class="delimiter">"</span></span>) !== <span class="predefined-constant">false</span>){
                      <span class="local-variable">$is_known_host</span> = <span class="predefined-constant">true</span>;
                  }
   
                  <span class="keyword">while</span> (<span class="predefined">strpos</span>(<span class="local-variable">$domain</span>, <span class="string"><span class="delimiter">'</span><span class="content">.</span><span class="delimiter">'</span></span>) !== <span class="predefined-constant">false</span>) {
                          <span class="local-variable">$domain</span> = <span class="predefined">explode</span>(<span class="string"><span class="delimiter">'</span><span class="content">.</span><span class="delimiter">'</span></span>, <span class="local-variable">$domain</span>);
                          <span class="predefined">array_shift</span>(<span class="local-variable">$domain</span>);
                          <span class="local-variable">$domain</span> = <span class="predefined">implode</span>(<span class="string"><span class="delimiter">'</span><span class="content">.</span><span class="delimiter">'</span></span>, <span class="local-variable">$domain</span>);
   
                          <span class="keyword">if</span> (<span class="predefined">strpos</span>(<span class="local-variable">$known_domaines</span>, <span class="string"><span class="delimiter">"</span><span class="content"> .</span><span class="local-variable">$domain</span><span class="content"> </span><span class="delimiter">"</span></span>) !== <span class="predefined-constant">false</span>) {
                              <span class="local-variable">$is_known_host</span> = <span class="predefined-constant">true</span>;
                          }
                  }
          } 
  </span>
  Télécharger

  Cordialement
  Equipement

• Trying to convert code to be compatible with macOS by not using the .exe version of FFmpeg and FFmprobe. Cant open the .mp4 file when i go to run code

  9 juillet 2024, par Bruno Hawkins

  I am attempting to edit some code in python for extracting frames from a video (using parallel processing to make it faster) a friend created that works on windows, so that it can be used on macOS. However, i am running into some issues and i am not sure what the problem is.

  


  Essentially, when i go to run the frame extractor and try to select a video in the formats specified, it wont let me select it.

  


  i have commented my code best i can. i am an amateur programmer so apologies if it is straightforward.

  


  import os
import subprocess
import multiprocessing
import tkinter as tk
from tkinter import ttk, filedialog, messagebox

def extract_frames(video_path, output_folder, fps, start_time, duration, process_number):
    video_name = os.path.splitext(os.path.basename(video_path))[0]
    part_output_folder = os.path.join(output_folder, f"part_{process_number}")
    if not os.path.exists(part_output_folder):
        os.makedirs(part_output_folder)

    # Using 'ffmpeg' instead of 'ffmpeg.exe' for macOS compatibility
    ffmpeg_command = [
        'ffmpeg', '-ss', str(start_time), '-t', str(duration), '-i', video_path, '-vf', f'fps={fps}',
        os.path.join(part_output_folder, f'{video_name}_frame_%07d.png')
    ]

    print(f"Running FFmpeg command: {' '.join(ffmpeg_command)}")

    try:
        process = subprocess.run(ffmpeg_command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        if process.returncode != 0:
            print(f"Cannot process the file {video_path}: {process.stderr.decode('utf-8')}")
            return part_output_folder, 0
    except Exception as e:
        print(f"Failed to run FFmpeg command: {str(e)}")
        return part_output_folder, 0

    frame_count = len([f for f in os.listdir(part_output_folder) if f.endswith('.png')])
    return part_output_folder, frame_count

def worker_function(queue, video_path, output_folder, fps, start_time, duration, process_number):
    result = extract_frames(video_path, output_folder, fps, start_time, duration, process_number)
    queue.put(result)

def parallel_frame_extraction(video_path, output_folder, fps, num_processes):
    # Use 'ffprobe' instead of 'ffprobe.exe' for macOS compatibility
    ffprobe_command = [
        'ffprobe', '-v', 'error', '-select_streams', 'v:0', '-show_entries', 'format=duration', '-of',
        'default=noprint_wrappers=1:nokey=1', video_path
    ]

    try:
        result = subprocess.run(ffprobe_command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        duration = float(result.stdout.strip())
    except Exception as e:
        messagebox.showerror("Error", f"Failed to get video duration: {str(e)}")
        return

    chunk_duration = duration / num_processes
    processes = []
    manager = multiprocessing.Manager()
    queue = manager.Queue()

    if not os.path.exists(output_folder):
        os.makedirs(output_folder)

    for i in range(num_processes):
        start_time = i * chunk_duration
        p = multiprocessing.Process(target=worker_function,
                                    args=(queue, video_path, output_folder, fps, start_time, chunk_duration, i))
        p.start()
        processes.append(p)

    for p in processes:
        p.join()

    global_frame_offset = 0
    while not queue.empty():
        part_output_folder, frame_count = queue.get()
        frame_files = sorted([f for f in os.listdir(part_output_folder) if f.endswith('.png')])
        for i, frame_file in enumerate(frame_files):
            new_name = os.path.join(output_folder,
                                    f'{os.path.basename(video_path)}_frame_{global_frame_offset + i:07d}.png')
            os.rename(os.path.join(part_output_folder, frame_file), new_name)
        global_frame_offset += frame_count
        os.rmdir(part_output_folder)

    messagebox.showinfo("Complete",
                        f"Frame extraction completed for {video_path}. Total frames extracted: {global_frame_offset}")

def start_frame_extraction():
    video_path = filedialog.askopenfilename(filetypes=[("Video files", "*.mp4;*.avi;*.mkv")])
    if not video_path:
        return

    output_folder = output_folder_var.get()
    if not output_folder:
        return

    fps = int(fps_var.get())
    num_processes = int(num_processes_var.get())

    parallel_frame_extraction(video_path, output_folder, fps, num_processes)

if __name__ == "__main__":
    root = tk.Tk()
    root.title("Frame Extraction")

    output_folder_var = tk.StringVar()
    fps_var = tk.StringVar(value="1")
    num_processes_var = tk.StringVar(value="4")

    def browse_output_folder():
        folder_selected = filedialog.askdirectory()
        output_folder_var.set(folder_selected)

    tk.Label(root, text="Output Folder:").grid(row=0, column=0, padx=10, pady=10)
    tk.Entry(root, textvariable=output_folder_var, width=50).grid(row=0, column=1, padx=10, pady=10)
    tk.Button(root, text="Browse", command=browse_output_folder).grid(row=0, column=2, padx=10, pady=10)

    tk.Label(root, text="FPS:").grid(row=1, column=0, padx=10, pady=10)
    tk.Entry(root, textvariable=fps_var, width=10).grid(row=1, column=1, padx=10, pady=10)

    tk.Label(root, text="Number of Processes:").grid(row=2, column=0, padx=10, pady=10)
    tk.Entry(root, textvariable=num_processes_var, width=10).grid(row=2, column=1, padx=10, pady=10)

    tk.Button(root, text="Start Frame Extraction", command=start_frame_extraction).grid(row=3, column=0, columnspan=3,
                                                                                        padx=10, pady=20)

    root.mainloop()


  


  I tried changing the FFmpeg and FFmprobe path formats from

  


  ffmpeg_path = os.path.join(os.path.dirname(__file__), 'ffmpeg-7.0.1-essentials_build', 'bin', 'ffmpeg.exe')
ffprobe_path = os.path.join(os.path.dirname(__file__), 'ffmpeg-7.0.1-essentials_build', 'bin', 'ffprobe.exe')



  


  to

  


  ffmpeg_command = [
    'ffmpeg', '-ss', str(start_time), '-t', str(duration), '-i', video_path, '-vf', f'fps={fps}',
    os.path.join(part_output_folder, f'{video_name}_frame_%07d.png')
]

ffprobe_command = [
    'ffprobe', '-v', 'error', '-select_streams', 'v:0', '-show_entries', 'format=duration', '-of',
    'default=noprint_wrappers=1:nokey=1', video_path
]



  


  I found this online so im not sure if it is the correct thing to do.

  


  Thanks for any help.