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• My stitched frames colors looks very different from my original video, causing my video to not be able to stitch it back properly [closed]

  27 mai 2024, par Wer Wer

  I am trying to extract some frames off my video to do some form of steganography. I accidentally used a 120fps video, causing the files to be too big when i extract every single frame. To fix this, I decided to calculate how many frames is needed to hide the bits (LSB replacement for every 8 bit) and then extract only certain amount of frames. This means

  


  

  1. if i only need 1 frame, ill extract frame0.png

  


  2. ill remove frame0 from the original video

  


  3. encode my data into frame0.png

  


  4. stitch frame0 back into ffv1 video

  


  5. concatenate frame0 video to the rest of the video, frame0 video in front.

  


  


  I can do extraction and remove frame0 from the video. However, when looking at frame0.mkv and the original.mkv, i realised the colors seemed to be different.
Frame0.mkv
original.mkv

  


  This causes a glitch during the stitching of videos together, where the end of the video has some corrupted pixels. Not only that, it stops the video at where frame0 ends. I think those corrupted pixels were supposed to be original.mkv pixels, but they did not concatenate properly.
results.mkv

  


  I use an ffmpeg sub command to extract frames and stitch them

  


      def split_into_frames(self, ffv1_video, hidden_text_length):
        if not ffv1_video.endswith(".mkv"):
            ffv1_video += ".mkv"

        ffv1_video_path = os.path.join(self.here, ffv1_video)
        ffv1_video = cv2.VideoCapture(ffv1_video_path)

        currentframe = 0
        total_frame_bits = 0
        frames_to_remove = []

        while True:
            ret, frame = ffv1_video.read()
            if ret:
                name = os.path.join(self.here, "data", f"frame{currentframe}.png")
                print("Creating..." + name)
                cv2.imwrite(name, frame)

                current_frame_path = os.path.join(
                    self.here, "data", f"frame{currentframe}.png"
                )

                if os.path.exists(current_frame_path):
                    binary_data = self.read_frame_binary(current_frame_path)

                if (total_frame_bits // 8) >= hidden_text_length:
                    print("Complete")
                    break
                total_frame_bits += len(binary_data)
                frames_to_remove.append(currentframe)
                currentframe += 1
            else:
                print("Complete")
                break

        ffv1_video.release()

        # Remove the extracted frames from the original video
        self.remove_frames_from_video(ffv1_video_path, frames_to_remove)



  


  This code splits the video into the required number of frames. It checks if the total amount of frame bits is enough to encode the hidden text

  


  def remove_frames_from_video(self, input_video, frames_to_remove):
    if not input_video.endswith(".mkv"):
        input_video += ".mkv"

    input_video_path = os.path.join(self.here, input_video)

    # Create a filter string to exclude specific frames
    filter_str = (
        "select='not("
        + "+".join([f"eq(n\,{frame})" for frame in frames_to_remove])
        + ")',setpts=N/FRAME_RATE/TB"
    )

    # Temporary output video path
    output_video_path = os.path.join(self.here, "temp_output.mkv")

    command = [
        "ffmpeg",
        "-y",
        "-i",
        input_video_path,
        "-vf",
        filter_str,
        "-c:v",
        "ffv1",
        "-level",
        "3",
        "-coder",
        "1",
        "-context",
        "1",
        "-g",
        "1",
        "-slices",
        "4",
        "-slicecrc",
        "1",
        "-an",  # Remove audio
        output_video_path,
    ]

    try:
        subprocess.run(command, check=True)
        print(f"Frames removed. Temporary video created at {output_video_path}")

        # Replace the original video with the new video
        os.replace(output_video_path, input_video_path)
        print(f"Original video replaced with updated video at {input_video_path}")

        # Re-add the trimmed audio to the new video
        self.trim_audio_and_add_to_video(input_video_path, frames_to_remove)
    except subprocess.CalledProcessError as e:
        print(f"An error occurred: {e}")
        if os.path.exists(output_video_path):
            os.remove(output_video_path)

def trim_audio_and_add_to_video(self, video_path, frames_to_remove):
    # Calculate the new duration based on the remaining frames
    fps = 60  # Assuming the framerate is 60 fps
    total_frames_removed = len(frames_to_remove)
    original_duration = self.get_video_duration(video_path)
    new_duration = original_duration - (total_frames_removed / fps)

    # Extract and trim the audio
    audio_path = os.path.join(self.here, "trimmed_audio.aac")
    command_extract_trim = [
        "ffmpeg",
        "-y",
        "-i",
        video_path,
        "-t",
        str(new_duration),
        "-q:a",
        "0",
        "-map",
        "a",
        audio_path,
    ]
    try:
        subprocess.run(command_extract_trim, check=True)
        print(f"Audio successfully trimmed and extracted to {audio_path}")

        # Add the trimmed audio back to the video
        final_video_path = video_path.replace(".mkv", "_final.mkv")
        command_add_audio = [
            "ffmpeg",
            "-y",
            "-i",
            video_path,
            "-i",
            audio_path,
            "-c:v",
            "copy",
            "-c:a",
            "aac",
            "-strict",
            "experimental",
            final_video_path,
        ]
        subprocess.run(command_add_audio, check=True)
        print(f"Final video with trimmed audio created at {final_video_path}")

        # Replace the original video with the final video
        os.replace(final_video_path, video_path)
        print(f"Original video replaced with final video at {video_path}")
    except subprocess.CalledProcessError as e:
        print(f"An error occurred: {e}")

def get_video_duration(self, video_path):
    command = [
        "ffprobe",
        "-v",
        "error",
        "-show_entries",
        "format=duration",
        "-of",
        "default=noprint_wrappers=1:nokey=1",
        video_path,
    ]
    try:
        result = subprocess.run(
            command, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE
        )
        duration = float(result.stdout.decode().strip())
        return duration
    except subprocess.CalledProcessError as e:
        print(f"An error occurred while getting video duration: {e}")
        return 0.0


  


  here ill remove all the frames that has been extracted from the video

  


  def stitch_frames_to_video(self, ffv1_video, framerate=60):
    # this command is another ffmpeg subcommand.
    # it takes every single frame from data1 directory and stitch it back into a ffv1 video
    if not ffv1_video.endswith(".mkv"):
        ffv1_video += ".mkv"

    output_video_path = os.path.join(self.here, ffv1_video)

    command = [
        "ffmpeg",
        "-y",
        "-framerate",
        str(framerate),
        "-i",
        os.path.join(self.frames_directory, "frame%d.png"),
        "-c:v",
        "ffv1",
        "-level",
        "3",
        "-coder",
        "1",
        "-context",
        "1",
        "-g",
        "1",
        "-slices",
        "4",
        "-slicecrc",
        "1",
        output_video_path,
    ]

    try:
        subprocess.run(command, check=True)
        print(f"Video successfully created at {output_video_path}")
    except subprocess.CalledProcessError as e:
        print(f"An error occurred: {e}")


  


  after encoding the frames, ill try to stitch the frames back into ffv1 video

  


  def concatenate_videos(self, video1_path, video2_path, output_path):
    if not video1_path.endswith(".mkv"):
        video1_path += ".mkv"
    if not video2_path.endswith(".mkv"):
        video2_path += ".mkv"
    if not output_path.endswith(".mkv"):
        output_path += ".mkv"

    video1_path = os.path.join(self.here, video1_path)
    video2_path = os.path.join(self.here, video2_path)
    output_video_path = os.path.join(self.here, output_path)

    # Create a text file with the paths of the videos to concatenate
    concat_list_path = os.path.join(self.here, "concat_list.txt")
    with open(concat_list_path, "w") as f:
        f.write(f"file '{video1_path}'\n")
        f.write(f"file '{video2_path}'\n")

    command = [
        "ffmpeg",
        "-y",
        "-f",
        "concat",
        "-safe",
        "0",
        "-i",
        concat_list_path,
        "-c",
        "copy",
        output_video_path,
    ]

    try:
        subprocess.run(command, check=True)
        print(f"Videos successfully concatenated into {output_video_path}")
        os.remove(concat_list_path)  # Clean up the temporary file
    except subprocess.CalledProcessError as e:
        print(f"An error occurred: {e}")


  


  now i try to concatenate the frames video with the original video, but it is corrupting as the colors are different.

  


  this code does the other processing by removing all the extracted frames from the video, as well as trimming the audio (but i think ill be removing the audio trimming as i realised it is not needed at all)

  


  I think its because .png frames will lose colors when they get extracted out. The only work around I know is to extract every single frame. But this causes the program to run too long as for a 12 second video, I will extract 700++ frames. Is there a way to fix this ?

  


  my full code

  


  import json
import os
import shutil
import magic
import ffmpeg
import cv2
import numpy as np
import subprocess
from PIL import Image
import glob


import json
import os
import shutil
import magic
import ffmpeg
import cv2
import numpy as np
import subprocess
from PIL import Image
import glob


class FFV1Steganography:
    def __init__(self):
        self.here = os.path.dirname(os.path.abspath(__file__))

        # Create a folder to save the frames
        self.frames_directory = os.path.join(self.here, "data")
        try:
            if not os.path.exists(self.frames_directory):
                os.makedirs(self.frames_directory)
        except OSError:
            print("Error: Creating directory of data")

    def read_hidden_text(self, filename):
        file_path_txt = os.path.join(self.here, filename)
        # Read the content of the file in binary mode
        with open(file_path_txt, "rb") as f:
            hidden_text_content = f.read()
        return hidden_text_content

    def calculate_length_of_hidden_text(self, filename):
        hidden_text_content = self.read_hidden_text(filename)
        # Convert each byte to its binary representation and join them
        return len("".join(format(byte, "08b") for byte in hidden_text_content))

    def find_raw_video_file(self, filename):
        file_extensions = [".mp4", ".mkv", ".avi"]
        for ext in file_extensions:
            file_path = os.path.join(self.here, filename + ext)
            if os.path.isfile(file_path):
                return file_path
        return None

    def convert_video(self, input_file, ffv1_video):
        # this function is the same as running this command line
        # ffmpeg -i video.mp4 -t 12 -c:v ffv1 -level 3 -coder 1 -context 1 -g 1 -slices 4 -slicecrc 1 -c:a copy output.mkv

        # in order to run any ffmpeg subprocess, you have to have ffmpeg installed into the computer.
        # https://ffmpeg.org/download.html

        # WARNING:
        # the ffmpeg you should download is not the same as the ffmpeg library for python.
        # you need to download the exe from the link above, then add ffmpeg bin directory to system variables
        output_file = os.path.join(self.here, ffv1_video)

        if not output_file.endswith(".mkv"):
            output_file += ".mkv"

        command = [
            "ffmpeg",
            "-y",
            "-i",
            input_file,
            "-t",
            "12",
            "-c:v",
            "ffv1",
            "-level",
            "3",
            "-coder",
            "1",
            "-context",
            "1",
            "-g",
            "1",
            "-slices",
            "4",
            "-slicecrc",
            "1",
            "-c:a",
            "copy",
            output_file,
        ]

        try:
            subprocess.run(command, check=True)
            print(f"Conversion successful: {output_file}")
            return output_file
        except subprocess.CalledProcessError as e:
            print(f"Error during conversion: {e}")

    def extract_audio(self, ffv1_video, audio_path):
        # Ensure the audio output file has the correct extension
        if not audio_path.endswith(".aac"):
            audio_path += ".aac"

        # Full path to the extracted audio file
        extracted_audio = os.path.join(self.here, audio_path)

        if not ffv1_video.endswith(".mkv"):
            ffv1_video += ".mkv"

        command = [
            "ffmpeg",
            "-i",
            ffv1_video,
            "-q:a",
            "0",
            "-map",
            "a",
            extracted_audio,
        ]
        try:
            result = subprocess.run(
                command, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE
            )
            print(f"Audio successfully extracted to {extracted_audio}")
            print(result.stdout.decode())
            print(result.stderr.decode())
        except subprocess.CalledProcessError as e:
            print(f"An error occurred: {e}")
            print(e.stdout.decode())
            print(e.stderr.decode())

    def read_frame_binary(self, frame_path):
        # Open the image and convert to binary
        with open(frame_path, "rb") as f:
            binary_content = f.read()
            binary_string = "".join(format(byte, "08b") for byte in binary_content)
        return binary_string

    def remove_frames_from_video(self, input_video, frames_to_remove):
        if not input_video.endswith(".mkv"):
            input_video += ".mkv"

        input_video_path = os.path.join(self.here, input_video)

        # Create a filter string to exclude specific frames
        filter_str = (
            "select='not("
            + "+".join([f"eq(n\,{frame})" for frame in frames_to_remove])
            + ")',setpts=N/FRAME_RATE/TB"
        )

        # Temporary output video path
        output_video_path = os.path.join(self.here, "temp_output.mkv")

        command = [
            "ffmpeg",
            "-y",
            "-i",
            input_video_path,
            "-vf",
            filter_str,
            "-c:v",
            "ffv1",
            "-level",
            "3",
            "-coder",
            "1",
            "-context",
            "1",
            "-g",
            "1",
            "-slices",
            "4",
            "-slicecrc",
            "1",
            "-an",  # Remove audio
            output_video_path,
        ]

        try:
            subprocess.run(command, check=True)
            print(f"Frames removed. Temporary video created at {output_video_path}")

            # Replace the original video with the new video
            os.replace(output_video_path, input_video_path)
            print(f"Original video replaced with updated video at {input_video_path}")

            # Re-add the trimmed audio to the new video
            self.trim_audio_and_add_to_video(input_video_path, frames_to_remove)
        except subprocess.CalledProcessError as e:
            print(f"An error occurred: {e}")
            if os.path.exists(output_video_path):
                os.remove(output_video_path)

    def trim_audio_and_add_to_video(self, video_path, frames_to_remove):
        # Calculate the new duration based on the remaining frames
        fps = 60  # Assuming the framerate is 60 fps
        total_frames_removed = len(frames_to_remove)
        original_duration = self.get_video_duration(video_path)
        new_duration = original_duration - (total_frames_removed / fps)

        # Extract and trim the audio
        audio_path = os.path.join(self.here, "trimmed_audio.aac")
        command_extract_trim = [
            "ffmpeg",
            "-y",
            "-i",
            video_path,
            "-t",
            str(new_duration),
            "-q:a",
            "0",
            "-map",
            "a",
            audio_path,
        ]
        try:
            subprocess.run(command_extract_trim, check=True)
            print(f"Audio successfully trimmed and extracted to {audio_path}")

            # Add the trimmed audio back to the video
            final_video_path = video_path.replace(".mkv", "_final.mkv")
            command_add_audio = [
                "ffmpeg",
                "-y",
                "-i",
                video_path,
                "-i",
                audio_path,
                "-c:v",
                "copy",
                "-c:a",
                "aac",
                "-strict",
                "experimental",
                final_video_path,
            ]
            subprocess.run(command_add_audio, check=True)
            print(f"Final video with trimmed audio created at {final_video_path}")

            # Replace the original video with the final video
            os.replace(final_video_path, video_path)
            print(f"Original video replaced with final video at {video_path}")
        except subprocess.CalledProcessError as e:
            print(f"An error occurred: {e}")

    def get_video_duration(self, video_path):
        command = [
            "ffprobe",
            "-v",
            "error",
            "-show_entries",
            "format=duration",
            "-of",
            "default=noprint_wrappers=1:nokey=1",
            video_path,
        ]
        try:
            result = subprocess.run(
                command, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE
            )
            duration = float(result.stdout.decode().strip())
            return duration
        except subprocess.CalledProcessError as e:
            print(f"An error occurred while getting video duration: {e}")
            return 0.0

    def split_into_frames(self, ffv1_video, hidden_text_length):
        if not ffv1_video.endswith(".mkv"):
            ffv1_video += ".mkv"

        ffv1_video_path = os.path.join(self.here, ffv1_video)
        ffv1_video = cv2.VideoCapture(ffv1_video_path)

        currentframe = 0
        total_frame_bits = 0
        frames_to_remove = []

        while True:
            ret, frame = ffv1_video.read()
            if ret:
                name = os.path.join(self.here, "data", f"frame{currentframe}.png")
                print("Creating..." + name)
                cv2.imwrite(name, frame)

                current_frame_path = os.path.join(
                    self.here, "data", f"frame{currentframe}.png"
                )

                if os.path.exists(current_frame_path):
                    binary_data = self.read_frame_binary(current_frame_path)

                if (total_frame_bits // 8) >= hidden_text_length:
                    print("Complete")
                    break
                total_frame_bits += len(binary_data)
                frames_to_remove.append(currentframe)
                currentframe += 1
            else:
                print("Complete")
                break

        ffv1_video.release()

        # Remove the extracted frames from the original video
        self.remove_frames_from_video(ffv1_video_path, frames_to_remove)

    def stitch_frames_to_video(self, ffv1_video, framerate=60):
        # this command is another ffmpeg subcommand.
        # it takes every single frame from data1 directory and stitch it back into a ffv1 video
        if not ffv1_video.endswith(".mkv"):
            ffv1_video += ".mkv"

        output_video_path = os.path.join(self.here, ffv1_video)

        command = [
            "ffmpeg",
            "-y",
            "-framerate",
            str(framerate),
            "-i",
            os.path.join(self.frames_directory, "frame%d.png"),
            "-c:v",
            "ffv1",
            "-level",
            "3",
            "-coder",
            "1",
            "-context",
            "1",
            "-g",
            "1",
            "-slices",
            "4",
            "-slicecrc",
            "1",
            output_video_path,
        ]

        try:
            subprocess.run(command, check=True)
            print(f"Video successfully created at {output_video_path}")
        except subprocess.CalledProcessError as e:
            print(f"An error occurred: {e}")

    def add_audio_to_video(self, encoded_video, audio_path, final_video):
        # the audio will be lost during splitting and restitching.
        # that is why previously we separated the audio from video and saved it as aac.
        # now, we can put the audio back into the video, again using ffmpeg subcommand.

        if not encoded_video.endswith(".mkv"):
            encoded_video += ".mkv"

        if not final_video.endswith(".mkv"):
            final_video += ".mkv"

        if not audio_path.endswith(".aac"):
            audio_path += ".aac"

        final_output_path = os.path.join(self.here, final_video)

        command = [
            "ffmpeg",
            "-y",
            "-i",
            os.path.join(self.here, encoded_video),
            "-i",
            os.path.join(self.here, audio_path),
            "-c:v",
            "copy",
            "-c:a",
            "aac",
            "-strict",
            "experimental",
            final_output_path,
        ]
        try:
            subprocess.run(command, check=True)
            print(f"Final video with audio created at {final_output_path}")
        except subprocess.CalledProcessError as e:
            print(f"An error occurred: {e}")

    def concatenate_videos(self, video1_path, video2_path, output_path):
        if not video1_path.endswith(".mkv"):
            video1_path += ".mkv"
        if not video2_path.endswith(".mkv"):
            video2_path += ".mkv"
        if not output_path.endswith(".mkv"):
            output_path += ".mkv"

        video1_path = os.path.join(self.here, video1_path)
        video2_path = os.path.join(self.here, video2_path)
        output_video_path = os.path.join(self.here, output_path)

        # Create a text file with the paths of the videos to concatenate
        concat_list_path = os.path.join(self.here, "concat_list.txt")
        with open(concat_list_path, "w") as f:
            f.write(f"file '{video1_path}'\n")
            f.write(f"file '{video2_path}'\n")

        command = [
            "ffmpeg",
            "-y",
            "-f",
            "concat",
            "-safe",
            "0",
            "-i",
            concat_list_path,
            "-c",
            "copy",
            output_video_path,
        ]

        try:
            subprocess.run(command, check=True)
            print(f"Videos successfully concatenated into {output_video_path}")
            os.remove(concat_list_path)  # Clean up the temporary file
        except subprocess.CalledProcessError as e:
            print(f"An error occurred: {e}")

    def cleanup(self, files_to_delete):
        # Delete specified files
        for file in files_to_delete:
            file_path = os.path.join(self.here, file)
            if os.path.exists(file_path):
                os.remove(file_path)
                print(f"Deleted file: {file_path}")
            else:
                print(f"File not found: {file_path}")

        # Delete the frames directory and its contents
        if os.path.exists(self.frames_directory):
            shutil.rmtree(self.frames_directory)
            print(f"Deleted directory and its contents: {self.frames_directory}")
        else:
            print(f"Directory not found: {self.frames_directory}")


if __name__ == "__main__":
    stego = FFV1Steganography()

    # original video (mp4,mkv,avi)
    original_video = "video"
    # converted ffv1 video
    ffv1_video = "output"
    # extracted audio
    extracted_audio = "audio"
    # encoded video without sound
    encoded_video = "encoded"
    # final result video, encoded, with sound
    final_video = "result"

    # region --hidden text processing --
    hidden_text = stego.read_hidden_text("hiddentext.txt")
    hidden_text_length = stego.calculate_length_of_hidden_text("hiddentext.txt")
    # endregion

    # region -- raw video locating --
    raw_video_file = stego.find_raw_video_file(original_video)
    if raw_video_file:
        print(f"Found video file: {raw_video_file}")
    else:
        print("video.mp4 not found.")
    # endregion

    # region -- video processing INPUT--
    # converted_video_file = stego.convert_video(raw_video_file, ffv1_video)
    # if converted_video_file and os.path.exists(converted_video_file):
    #     stego.extract_audio(converted_video_file, extracted_audio)
    # else:
    #     print(f"Conversion failed: {converted_video_file} not found.")

    # stego.split_into_frames(ffv1_video, hidden_text_length * 50000)
    # endregion

    # region -- video processing RESULT --
    # stego.stitch_frames_to_video(encoded_video)
    stego.concatenate_videos(encoded_video, ffv1_video, final_video)
    # stego.add_audio_to_video(final_video, extracted_audio, final_video)
    # endregion

    # region -- cleanup --
    files_to_delete = [
        extracted_audio + ".aac",
        encoded_video + ".mkv",
        ffv1_video + ".mkv",
    ]

 stego.cleanup(files_to_delete)
    # endregion







  


  Edit for results expectations :
I dont know if there is a way to match the exact color encoding between the stitched png frames and the rest of the ffv1 video. Is there a way I can extract the frames such that the color, encoding or anything I may not know about ffv1 match the original ffv1 video ?

  


• Statically built FFMPEG binary segmentation fault

  12 février 2020, par stevendesu

  I want to create a custom build of FFMPEG which rips out everything except for the ability to transmux HLS videos to MP4, and I need this build to be 100% static with no external dependencies

  I tried using the following configuration :

  ./configure \
  
      --extra-cflags='-static -static-libstdc++ -static-libgcc' \
  
      --extra-cxxflags='-static -static-libstdc++ -static-libgcc' \
  
      --extra-ldflags='-static -static-libstdc++ -static-libgcc' \
  
      --pkg-config-flags='--static' \
  
      --enable-static \
  
      --disable-shared \
  
      --disable-runtime-cpudetect \
  
      --disable-autodetect \
  
      --disable-ffplay \
  
      --disable-ffprobe \
  
      --disable-doc \
  
      --disable-avdevice \
  
      --disable-swresample \
  
      --disable-swscale \
  
      --disable-postproc \
  
      --disable-pthreads \
  
      --disable-w32threads \
  
      --disable-os2threads \
  
      --enable-network \
  
      --disable-dct \
  
      --disable-dwt \
  
      --disable-error-resilience \
  
      --disable-lsp \
  
      --disable-lzo \
  
      --disable-mdct \
  
      --disable-rdft \
  
      --disable-fft \
  
      --disable-faan \
  
      --disable-pixelutils \
  
      --disable-encoders \
  
      --disable-decoders \
  
      --disable-hwaccels \
  
      --disable-muxers \
  
      --enable-muxer=mov \
  
      --enable-muxer=mp4 \
  
      --disable-demuxers \
  
      --enable-demuxer=hls \
  
      --enable-demuxer=mpegts \
  
      --enable-demuxer=h264 \
  
      --enable-demuxer=aac \
  
      --disable-parsers \
  
      --enable-parser=h264 \
  
      --enable-parser=aac \
  
      --disable-bsfs \
  
      --disable-protocols \
  
      --enable-protocol=tcp \
  
      --enable-protocol=tls \
  
      --enable-protocol=http \
  
      --enable-protocol=https \
  
      --enable-protocol=hls \
  
      --disable-indevs \
  
      --disable-outdevs \
  
      --disable-devices \
  
      --disable-filters \
  
      --disable-alsa \
  
      --disable-appkit \
  
      --disable-avfoundation \
  
      --disable-bzlib \
  
      --disable-coreimage \
  
      --disable-iconv \
  
      --disable-lzma \
  
      --enable-openssl \
  
      --disable-sndio \
  
      --disable-sdl2 \
  
      --disable-securetransport \
  
      --disable-xlib \
  
      --disable-zlib \
  
      --disable-amf \
  
      --disable-audiotoolbox \
  
      --disable-cuda-llvm \
  
      --disable-cuvid \
  
      --disable-d3d11va \
  
      --disable-dxva2 \
  
      --disable-ffnvcodec \
  
      --disable-nvdec \
  
      --disable-nvenc \
  
      --disable-v4l2-m2m \
  
      --disable-vaapi \
  
      --disable-vdpau \
  
      --disable-videotoolbox \
  
      --disable-debug

  This looked about like what I wanted :

  install prefix            /usr/local
  
  source path               .
  
  C compiler                gcc
  
  C library                 glibc
  
  ARCH                      x86 (generic)
  
  big-endian                no
  
  runtime cpu detection     no
  
  standalone assembly       yes
  
  x86 assembler             nasm
  
  MMX enabled               yes
  
  MMXEXT enabled            yes
  
  3DNow! enabled            yes
  
  3DNow! extended enabled   yes
  
  SSE enabled               yes
  
  SSSE3 enabled             yes
  
  AESNI enabled             yes
  
  AVX enabled               yes
  
  AVX2 enabled              yes
  
  AVX-512 enabled           yes
  
  XOP enabled               yes
  
  FMA3 enabled              yes
  
  FMA4 enabled              yes
  
  i686 features enabled     yes
  
  CMOV is fast              yes
  
  EBX available             yes
  
  EBP available             yes
  
  debug symbols             no
  
  strip symbols             yes
  
  optimize for size         no
  
  optimizations             yes
  
  static                    yes
  
  shared                    no
  
  postprocessing support    no
  
  network support           yes
  
  threading support         no
  
  safe bitstream reader     yes
  
  texi2html enabled         no
  
  perl enabled              yes
  
  pod2man enabled           yes
  
  makeinfo enabled          no
  
  makeinfo supports HTML    no
  
  
  
  External libraries:
  
  openssl
  
  
  
  External libraries providing hardware acceleration:
  
  
  
  Libraries:
  
  avcodec                 avfilter                avformat                avutil
  
  
  
  Programs:
  
  ffmpeg
  
  
  
  Enabled decoders:
  
  
  
  Enabled encoders:
  
  
  
  Enabled hwaccels:
  
  
  
  Enabled parsers:
  
  aac                     h264
  
  
  
  Enabled demuxers:
  
  aac                     h264                    hls                     mpegts
  
  
  
  Enabled muxers:
  
  mov                     mp4
  
  
  
  Enabled protocols:
  
  hls                     http                    https                   tcp                     tls
  
  
  
  Enabled filters:
  
  aformat                 anull                   atrim                   format                  hflip                   null                    transpose               trim                    vflip
  
  
  
  Enabled bsfs:
  
  null
  
  
  
  Enabled indevs:
  
  
  
  Enabled outdevs:
  
  
  
  License: LGPL version 2.1 or later

  It included several filters which I won’t ever need or use, but these filters are pulled in automatically if you don’t specify --disable-avfilter, and specifying --disable-avfilter prevents the ffmpeg binary from being produced. So I’m stuck with those.

  Using these parameters and then running make, I received a binary that was about 5.9 MB in size and looked right :

  $> ldd ffmpeg
  
          not a dynamic executable

  But when I try to run it :

  $> ./ffmpeg -version
  
  Segmentation fault

  Using valgrind to try and inspect the cause of the segmentation fault :

  $> valgrind ./ffmpeg -version
  
  .... lots of stuff ...
  
  ==61362== Jump to the invalid address stated on the next line
  
  ==61362==    at 0x0: ???
  
  ==61362==    by 0x70BB1B: ??? (in /src/FFmpeg/ffmpeg)
  
  ==61362==    by 0x70B2E6: ??? (in /src/FFmpeg/ffmpeg)
  
  ==61362==    by 0x4033F9: ??? (in /src/FFmpeg/ffmpeg)
  
  ==61362==    by 0x1FFF000677: ???
  
  ==61362==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
  
  ==61362==
  
  ==61362==
  
  ==61362== Process terminating with default action of signal 11 (SIGSEGV)
  
  ==61362==  Bad permissions for mapped region at address 0x0
  
  ==61362==    at 0x0: ???
  
  ==61362==    by 0x70BB1B: ??? (in /src/FFmpeg/ffmpeg)
  
  ==61362==    by 0x70B2E6: ??? (in /src/FFmpeg/ffmpeg)
  
  ==61362==    by 0x4033F9: ??? (in /src/FFmpeg/ffmpeg)
  
  ==61362==    by 0x1FFF000677: ???
  
  ==61362==
  
  ==61362== HEAP SUMMARY:
  
  ==61362==     in use at exit: 0 bytes in 0 blocks
  
  ==61362==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
  
  ==61362==
  
  ==61362== All heap blocks were freed -- no leaks are possible
  
  ==61362==
  
  ==61362== For counts of detected and suppressed errors, rerun with: -v
  
  ==61362== Use --track-origins=yes to see where uninitialised values come from
  
  ==61362== ERROR SUMMARY: 93 errors from 90 contexts (suppressed: 0 from 0)
  
  Segmentation fault

  Attempting to access memory at location 0x0 sounds like trying to follow a null pointer. But I’m not sure how to fix this.

  gdb backtrace

  When I first ran gdb ./ffmpeg gdb immediately gave me a segmentation fault and I wasn’t kicked into the gdb REPL, so I couldn’t investigate

  After rebuilding ffmpeg I was able to get in this time :

  $> gdb ./ffmpeg
  
  
  
  GNU gdb (Ubuntu 8.1-0ubuntu3.2) 8.1.0.20180409-git
  
  Copyright (C) 2018 Free Software Foundation, Inc.
  
  License GPLv3+: GNU GPL version 3 or later /gnu.org/licenses/gpl.html>
  
  This is free software: you are free to change and redistribute it.
  
  There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
  
  and "show warranty" for details.
  
  This GDB was configured as "x86_64-linux-gnu".
  
  Type "show configuration" for configuration details.
  
  For bug reporting instructions, please see:
  
  /www.gnu.org/software/gdb/bugs/>.
  
  Find the GDB manual and other documentation resources online at:
  
  /www.gnu.org/software/gdb/documentation/>.
  
  For help, type "help".
  
  Type "apropos word" to search for commands related to "word"...
  
  Reading symbols from ffmpeg...done.
  
  (gdb) r
  
  Starting program: /src/FFmpeg/ffmpeg
  
  warning: Error disabling address space randomization: Operation not permitted
  
  
  
  Program received signal SIGSEGV, Segmentation fault.
  
  0x0000000000000000 in ?? ()
  
  (gdb) bt
  
  #0  0x0000000000000000 in ?? ()
  
  #1  0x0000000000f9a8d5 in __register_frame_info_bases.part.6 ()
  
  #2  0x00000000004445fd in frame_dummy ()
  
  #3  0x0000000000000001 in ?? ()
  
  #4  0x0000000000ebd20c in __libc_csu_init ()
  
  #5  0x0000000000ebc9d7 in __libc_start_main ()
  
  #6  0x000000000044451a in _start ()
  
  (gdb)

  I tried grep’ing the code base for __register_frame_info_bases and found nothing. So I’m not really sure where to go from here

  A fix, but not an explanation

  By randomly removing configuration parameters and rebuilding I discovered that --disable-pthreads was causing the segmentation fault. When I remove this, ffmpeg runs just fine

  I don’t know why this is the case, though. Why would they make it possible to remove something that you need to run ?

• Virginia Consumer Data Protection Act (VCDPA) Guide

  27 septembre 2023, par Erin — Privacy

  Do you run a for-profit organisation in the United States that processes personal and sensitive consumer data ? If so, you may be concerned about the growing number of data privacy laws cropping up from state to state.

  Ever since the California Consumer Privacy Act (CCPA) came into effect on January 1, 2020, four other US states — Connecticut, Colorado, Utah and Virginia — have passed their own data privacy laws. Each law uses the CCPA as a foundation but slightly deviates from the formula. This is a problem for US organisations, as they cannot apply the same CCPA compliance framework everywhere else.

  In this article, you’ll learn what makes the Virginia Consumer Data Protection Act (VCDPA) unique and how to ensure compliance.

  What is the VCDPA ?

  Signed by Governor Ralph Northam on 2 March 2021, and brought into effect on 1 January 2023, the VCDPA is a new data privacy law. It gives Virginia residents certain rights regarding how organisations process their personal and sensitive consumer data.

  

  The law contains several provisions, which define :

  • Who must follow the VCDPA
  • Who is exempt from the VCDPA
  • The consumer rights of data subjects
  • Relevant terms, such as “consumers,” “personal data,” “sensitive data” and the “sale of personal data”
  • The rights and responsibilities of data controllers
  • What applicable organisations must do to ensure VCDPA compliance

  These guidelines define the data collection practices that VCDPA-compliant organisations must comply with. The practices are designed to protect the rights of Virginia residents who have their personal or sensitive data collected.

  What are the consumer rights of VCDPA data subjects ?

  There are seven consumer rights that protect residents who fit the definition of “data subjects” under the new Virginia data privacy law. 

  

  A data subject is an “identified or identifiable natural person” who has their information collected. Personally identifiable information includes a person’s name, address, date of birth, religious beliefs, immigration status, status of child protection assessments, ethnic origin and more.

  Below is a detailed breakdown of each VCDPA consumer right :

  1. Right to know, access and confirm personal data : Data subjects have the right to know that their data is being collected, the right to access their data and the right to confirm that the data being collected is accurate and up to date.
  2. Right to delete personal data : Data subjects have the right to request that their collected personal or sensitive consumer data be deleted.
  3. Right to correct inaccurate personal data : Data subjects have the right to request that their collected data be corrected.
  4. Right to data portability : Data subjects have the right to obtain their collected data and, when reasonable and possible, request that their collected data be transferred from one data controller to another.
  5. Right to opt out of data processing activity : Data subjects have the right to opt out of having their personal or sensitive data collected.
  6. Right to opt out of the sale of personal and sensitive consumer data : Data subjects have the right to opt out of having their collected data sold to third parties.

  Right to not be discriminated against for exercising one’s rights : Data subjects have the right to not be discriminated against for exercising their right to not have their personal or sensitive consumer data collected, processed and sold to third parties for targeted advertising or other purposes.

  Who must comply with the VCDPA ?

  The VCDPA applies to for-profit organisations. Specifically, those that operate and offer products or services in the state of Virginia.

  

  Additionally, for-profit organisations that fit under either of these two categories must comply with the VCDPA :

  • Collect and process the personal data of at least 100,000 Virginia residents within a financial year or
  • Collect and process the personal data of at least 25,000 Virginia residents and receive at least 50% of gross revenue by selling personal or sensitive data.

  If a for-profit organisation resides out of the state of Virginia and falls into one of the categories above, they must comply with the VCDPA. Eligibility requirements also apply, regardless of the revenue threshold of the organisation in question. Large organisations can avoid VCDPA compliance if they don’t meet either of the above two eligibility requirements.

  What types of consumer data does the VCDPA protect ?

  The two main types of data that apply to the VCDPA are personal and sensitive data. 

  

  Personal data is either identified or personally identifiable information, such as home address, date of birth or phone number. Information that is publicly available or has been de-identified (dissociated with a natural person or entity) is not considered personal data.

  Sensitive data is a category of personal data. It’s data that’s either the collected data of a known child or data that can be used to form an opinion about a natural person or individual. Examples of sensitive data include information about a person’s ethnicity, religion, political beliefs and sexual orientation. 

  It’s important that VCDPA-compliant organisations understand the difference between the two data types, as failure to do so could result in penalties of up to $7,500 per violation. For instance, if an organisation wants to collect sensitive data (and they have a valid reason to do so), they must first ask for consent from consumers. If the organisation in question fails to do so, then they’ll be in violation of the VCDPA, and may be subject to multiple penalties — equal to however many violations they incur.

  A 5-step VCDPA compliance framework

  Getting up to speed with the terms of the VCDPA can be challenging, especially if this is your first time encountering such a law. That said, even organisations that have experience with data privacy laws should still take the time to understand the VCDPA.

  

  Here’s a simple 5-step VCDPA compliance framework to follow.

  1. Assess data

  First off, take the time to become familiar with the Virginia Consumer Data Protection Act (VCDPA). Then, read the content from the ‘Who does the VCDPA apply to’ section of this article, and use this information to determine if the law applies to your organisation.

  How do you know if you reach the data subject threshold ? Easy. Use a web analytics platform like Matomo to see where your web visitors are, how many of them (from that specific region) are visiting your website and how many of them you’re collecting personal or sensitive data from.

  To do this in Matomo, simply open the dashboard, look at the “Locations” section and use the information on display to see how many Virginia residents are visiting your website.

  

  Using the dashboard will help you determine if the VCDPA applies to your company.

  2. Evaluate your privacy practices

  Review your existing privacy policies and practices and update them to comply with the VCDPA. Ensure your data collection practices protect the confidentiality, integrity and accessibility of your visitors.

  One way to do this is to automatically anonymise visitor IPs, which you can do in Matomo — in fact, the feature is automatically set to default. 

  

  Another great thing about IP anonymisation is that after a visitor leaves your website, any evidence of them ever visiting is gone, and such information cannot be tracked by anyone else. 

  3. Inform data subjects of their rights

  To ensure VCDPA compliance in your organisation, you must inform your data subjects of their rights, including their right to access their data, their right to transfer their data to another controller and their right to opt out of your data collection efforts.

  That last point is one of the most important, and to ensure that you’re ready to respond to consumer rights requests, you should prepare an opt-out form in advance. If a visitor wants to opt out from tracking, they’ll be able to do so quickly and easily. Not only will this help you be VCDPA compliant, but your visitors will also appreciate the fact that you take their privacy seriously.

  

  To create an opt-out form in Matomo, visit the privacy settings section (click on the cog icon in the top menu) and click on the “Users opt-out” menu item under the Privacy section. After creating the form, you can then customise and publish the form as a snippet of HTML code that you can place on the pages of your website.

  4. Review vendor contracts

  Depending on the nature of your organisation, you may have vendor contracts with a third-party business associate. These are individuals or organisations, separate from your own, that contribute to the successful delivery of your products and services.

  You may also engage with third parties that process the data you collect, as is the case for many website owners that use Google Analytics (to which there are many alternatives) to convert visitor data into insights. 

  Financial institutions, such as stock exchange companies, also rely on third-party data for trading. If this is the case for you, then you likely have a Data Processing Agreement (DPA) in place — a legally binding document between you (the data controller, who dictates how and why the collected data is used) and the data processor (who processes the data you provide to them).

  To ensure that your DPA is VCDPA compliant, make sure it contains the following items :

  • Definition of terms
  • Instructions for processing data
  • Limits of use (explain what all parties can and cannot do with the collected data)
  • Physical data security practices (e.g., potential risks, risk of harm and control measures)
  • Data subject rights
  • Consumer request policies (i.e., must respond within 45 days of receipt)
  • Privacy notices and policies

  5. Seek expert legal advice

  To ensure your organisation is fully VCDPA compliant, consider speaking to a data and privacy lawyer. They can help you better understand the specifics of the law, advise you on where you fall short of compliance and what you must do to become VCDPA compliant.

  Data privacy lawyers can also help you draft a meaningful privacy notice, which may be useful in modifying your existing DPAs or creating new ones. If needed, they can also advise you on areas of compliance with other state-specific data protection acts, such as the CCPA and newly released laws in Colorado, Connecticut and Utah.

  How does the VCDPA differ from the CCPA ?

  Although the VCDPA has many similarities to the CCPA, the two laws still have their own approach to applying the law. 

  Here’s a quick breakdown of the main differences that set these laws apart.

  Definition of a consumer

  Under the VCDPA, a consumer is a “natural person who is a Virginia resident acting in an individual or household context.” Meanwhile, under the CCPA, a consumer is a “natural person who is a California resident acting in an individual or household context.” However, the VCDPA omits people in employment contexts, while the CCPA doesn’t. Hence, organisations don’t need to consider employee data.

  Sale of personal data

  The VCDPA defines the “sale of personal data” as an exchange “for monetary consideration” by the data controller to a data processor or third party. This means that, under the VCDPA, an act is only considered a “sale of personal data” if there is monetary value attached to the transaction.

  This contrasts with the CCPA, where that law also counts “other valuable considerations” as a factor when determining if the sale of personal data has occurred.

  Right to opt out

  Just like the CCPA, the VCDPA clearly outlines that organisations must respond to a user request to opt out of tracking. However, unlike the CCPA, the VCDPA does not give organisations any exceptions to such a right. This means that, even if the organisation believes that the request is impractical or hard to pull off, it must comply with the request under any circumstances, even in instances of hardship.

  Ensure VCDPA compliance with Matomo

  The VCDPA, like many other data privacy laws in the US, is designed to enhance the rights of Virginia consumers who have their personal or sensitive data collected and processed. Fortunately, this is where platforms like Matomo can help.

  Matomo is a powerful web analytics platform that has built-in features to help you comply with the VCDPA. These include options like :

  • Cookie-less tracking
  • Creating consumer consent and opt-out forms
  • Giving consumers access to their personal data

  Try out the free 21-day Matomo trial today. No credit card required.