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• How to Bulk Speed UP and Crop Videos FFMPEG

  6 septembre 2023, par Usemo Shank

  I have videos in (input) folder that is located on the root of the script, I also have output folder on the root, The input folder has several videos that i want to speed up in bulk by 1.1 percent, I also want to cropt the videos by 90 percent (Meaning 90 Percent of original video is visible).

  


  I have a code that does not function well. Here is the code I have

  


   import os
import subprocess

# Define input and output directories
input_folder = "input"
output_folder = "output"

# Create the output directory if it doesn't exist
if not os.path.exists(output_folder):
    os.makedirs(output_folder)

# List all video files in the input directory
input_files = [f for f in os.listdir(input_folder) if f.endswith(('.mp4', '.avi', '.mkv'))]

# Speed up and crop each video
for input_file in input_files:
    input_path = os.path.join(input_folder, input_file)
    output_file = os.path.splitext(input_file)[0] + "_speed_crop.mp4"
    output_path = os.path.join(output_folder, output_file)

    # FFmpeg command to speed up video by 1.1x and crop to 90%
    ffmpeg_command = [
        "ffmpeg",
        "-i", input_path,
        "-vf", "setpts=1.1*PTS,crop=in_w*0.9:in_h*0.9",
        "-c:v", "libx264",
        "-crf", "20",
        "-c:a", "aac",
        "-strict", "experimental",
        output_path
    ]

    # Run FFmpeg command
    subprocess.run(ffmpeg_command)

print("Conversion complete.")


  


• getting black screen while trying to record dockerized lxde using ffmpeg

  16 mars 2023, par Itzik.B

  I have created a docker image that has LXDE and TightVNCServer.

  


  # Pull base image.
FROM ubuntu

# Install LXDE and VNC server.
RUN apt-get update
RUN apt-get install -y xvfb
RUN DEBIAN_FRONTEND=noninteractive apt-get install -y lxde-core lxterminal tightvncserver
RUN rm -rf /var/lib/apt/lists/*
RUN touch /root/.Xresources
RUN touch /root/.Xauthority
COPY xstartup /root/.vnc/xstartup
RUN chmod +x /root/.vnc/xstartup
#Install Node.js & npm

# Define working directory.
WORKDIR /data

COPY * /data

RUN apt-get install -y ffmpeg


  


  I am running this container using this command :

  


  docker run -it --rm -v /data:/data -p 5901:5901 -e USER=root ubuntudsktp  bash -c "vncserver :1 -geometry 1280x800 -depth 24 && tail -F /root/.vnc/*.log"

  


  I am logging into this container using VNC and running this command to record the whole screen :

  


  ffmpeg -f x11grab -i :1.0 output.webm

  


  After the recording was over, I opened the video and I could see that the video is completely blank(black screen).

  


  I know there is a "screen" that I need to tell ffmpeg to record but its works only on -i :1.0.

  


  I have also tried to run it using :

  


  DISPLAY=:1 ffmpeg -f x11grab -i :1.0 output.webm
And the results are the same.

  


  What I am missing here ?

  


• How to accurately detect the start of the main beat and soundtracks in diverse audio tracks ?

  18 juin 2024, par SnoofFloof

  I'm working on a project where I need to edit soundtracks. The challenge is to detect when the main beat and melody of any given soundtrack is properly developed. I am certain there is better terminology to describe what I am aiming for, but ideally, I want to skip the "build-up" and immediately have the song starting at the "main part". This needs to work for various songs across different genres, which often have different structures and onset patterns, making it difficult to streamline the process.

  


  For example :

  


  https://www.youtube.com/watch?v=P77CNtHrnmI -> I would want to my code to identify the onset at 0:24

  


  https://www.youtube.com/watch?v=OOsPCR8SyRo -> Onset detection at 0:12

  


  https://www.youtube.com/watch?v=XKiZBlelIzc -> Onset detection at 0:19

  


  I've tried using librosa to analyze the onset strength and detect beats, but the current implementation either detects the very beginning of the song or fails to consistently identify when the beat is fully developed.

  


  This was my approach ;

  


  def analyze_and_edit_audio(input_file, output_file):
    y, sr = librosa.load(input_file)
    tempo, beat_frames = librosa.beat.beat_track(y=y, sr=sr)
    beat_times = librosa.frames_to_time(beat_frames, sr=sr)
    main_beat_start = beat_times[0]


  


  I have very little experience with librosa/audio editing, so I would appreciate any suggestions you might have !