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• French CNIL recommends Piwik : the only analytics tool that does not require Cookie Consent

  29 octobre 2014, par Matthieu Aubry — Press Releases

  There has been recent and important changes in France regarding data privacy and the use of cookies. This blog post will introduce you to these changes and explain how you make your website compliant.

  Cookie Consent in the data freedom law

  Since the adoption of the EU Directive 2009/136/EC “Telecom Package”, Internet users must be informed and provide their prior consent to the storage of cookies on their computer. The use of cookies for advertising, analytics and social share buttons require the user’s consent :

  It is necessary to inform users of the presence, purpose and duration of the cookies placed in their browsers, and the means at their disposal to oppose it.

  What is a cookie ?

  Cookies are tracers placed on Internet users’ hard drives by the web hosts of the visited website. They allow the website to identify a single user across multiple visits with a unique identifier. Cookies may be used for various purposes : building up a shopping cart, storing a website’s language settings, or targeting advertising by monitoring the user’s web-browsing.

  Which cookies are exempt from the Cookie Consent rule ?

  France has exempted certain cookies from the cookie consent rule : for those cookies that are strictly necessary to offer the service sought after by the user you do not need to ask consent to user. Examples of such cookies are :

  • the shopping cart cookie,
  • authentication cookies,
  • short lived session cookies,
  • load balancer cookies,
  • certain first party analytics (such as Piwik cookies),
  • persistent cookies for interface personalisation.

  Asking users for consent for Analytics (tracking) Cookies

  For all cookies that are not exempted from the Cookie Consent then you will need to :

  • obtain consent from web users before placing or reading cookies and similar technologies,
  • clearly inform web users of the different purposes for which the cookies and similar technologies will be used,
  • propose a real choice to web users between accepting or refusing cookies and similar technologies.

  You don’t need Cookie Consent with Piwik

  The excellent news is that there is a way to bypass the Cookie Consent banner on your website :

  If you are using another analytics solution other than Piwik then you will need to ask users for consent. If you do not want to ask for consent then download and install Piwik or signup to Piwik Cloud to get started.

  If you are already using Piwik you need to do two simple things : (1) anonymise visitor IP addresses (at least two bytes) and (2) include the opt-out iframe solution in your website (learn more).

  Note that these recommendations currently only apply in France, but because the law is European we can expect similar findings in other European countries.

  CNIL recommends Piwik

  We are proud that the CNIL has identified Piwik as the only tool that respects all privacy requirements set by the European Telecom law.

  

  About the CNIL

  The CNIL is an independent administrative body that operates in accordance with the French data protection legislation. The CNIL has been entrusted with the general duty to inform people of the rights that the data protection legislation allows them.

  The role and responsabilities of the CNIL are :

  • to protect citizens and their data
  • to regulate and control processing of personal data
  • to inspect the security of data processing systems and applications, and impose penalties

  Piwik and Privacy

  At Piwik we love Privacy – our open analytics platform comes with built-in Privacy.

  Future of Privacy at Piwik

  Piwik is already the leader when it comes to respecting user privacy but we plan to continue improving privacy within the open analytics platform. For more information and specific ideas see Privacy enhancing issues in our issue tracker.

  References

  Learn more in these articles in French [fr] or English :

  • [fr] Sites web, cookies et autres traceurs
  • [fr] Comment me mettre en conformité avec la recommandation “Cookies” de la CNIL ?
  • [fr] Recommandation sur les cookies : obligations pour les responsables de sites ?
  • CNIL Starts Controlling Cookie Settings in October 2014
  • CNIL recommends Piwik for compliance with data protection laws

  Contact

  To learn more about Piwik, please visit piwik.org,

  Get in touch with the Piwik team : Contact information,

  For professional support contact Piwik PRO.

• Real time playback of two blended videos with alpha channel and synched audio in pygame ?

  22 décembre 2024, par Francesco Calderone

  I need to play two videos with synched sound in real-time with Pygame.
Pygame does not currently support video streams, so I am using a ffmpeg subprocess.
The first video is a prores422_hq. This is a background video with no alpha channel.
The second video is a prores4444 overlay video with an alpha channel, and it needs to be played in real-tim on top of the first video (with transparency).
All of this needs synched sound from the first base video only.

  


  I have tried many libraries, including pymovie pyav and opencv. The best result so far is to use a subprocess with ffmpeg.

  


  ffmpeg -i testing/stefano_prores422_hq.mov -stream_loop -1 -i testing/key_prores4444.mov -filter_complex "[1:v]format=rgba,colorchannelmixer=aa=1.0[overlay];[0:v][overlay]overlay" -f nut pipe:1 | ffplay -

  


  When running this in the terminal and playing with ffplay, everything is perfect, the overlay looks good, no dropped frames, and the sound is in synch.

  


  However, trying to feed that to pygame via a subprocess creates either video delays and drop frames or audio not in synch.

  


  EXAMPLE ONE :

  


  # SOUND IS NOT SYNCHED - sound is played via ffplay
import pygame
import subprocess
import numpy as np
import sys

def main():
    pygame.init()
    screen_width, screen_height = 1920, 1080
    screen = pygame.display.set_mode((screen_width, screen_height))
    pygame.display.set_caption("PyGame + FFmpeg Overlay with Audio")
    clock = pygame.time.Clock()

    # LAUNCH AUDIO-ONLY SUBPROCESS
    audio_cmd = [
        "ffplay",
        "-nodisp",          # no video window
        "-autoexit",        # exit when video ends
        "-loglevel", "quiet",
        "testing/stefano_prores422_hq.mov"
    ]
    audio_process = subprocess.Popen(audio_cmd)

    # LAUNCH VIDEO-OVERLAY SUBPROCESS
    ffmpeg_command = [
        "ffmpeg",
        "-i", "testing/stefano_prores422_hq.mov",
        "-stream_loop", "-1",         # loop alpha video
        "-i", "testing/key_prores4444.mov",
        "-filter_complex",
        "[1:v]format=rgba,colorchannelmixer=aa=1.0[overlay];"  # ensure alpha channel
        "[0:v][overlay]overlay",      # overlay second input onto first
        "-f", "rawvideo",             # output raw video
        "-pix_fmt", "rgba",           # RGBA format
        "pipe:1"                      # write to STDOUT
    ]
    video_process = subprocess.Popen(
        ffmpeg_command,
        stdout=subprocess.PIPE,
        stderr=subprocess.DEVNULL
    )
    frame_size = screen_width * screen_height * 4  # RGBA = 4 bytes/pixel
    running = True
    while running:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                running = False
                break

        raw_frame = video_process.stdout.read(frame_size)

        if len(raw_frame) < frame_size:
            running = False
            break
        # Convert raw bytes -> NumPy array -> PyGame surface
        frame_array = np.frombuffer(raw_frame, dtype=np.uint8)
        frame_array = frame_array.reshape((screen_height, screen_width, 4))
        frame_surface = pygame.image.frombuffer(frame_array.tobytes(), 
                                                (screen_width, screen_height), 
                                                "RGBA")
        screen.blit(frame_surface, (0, 0))
        pygame.display.flip()
        clock.tick(25)
    video_process.terminate()
    video_process.wait()
    audio_process.terminate()
    audio_process.wait()
    pygame.quit()
    sys.exit()

if __name__ == "__main__":
    main()



  


  EXAMPLE TWO

  


  # NO VIDEO OVERLAY - SOUND SYNCHED
import ffmpeg
import pygame
import sys
import numpy as np
import tempfile
import os

def extract_audio(input_file, output_file):
    """Extract audio from video file to temporary WAV file"""
    (
        ffmpeg
        .input(input_file)
        .output(output_file, acodec='pcm_s16le', ac=2, ar='44100')
        .overwrite_output()
        .run(capture_stdout=True, capture_stderr=True)
    )

def get_video_fps(input_file):
    probe = ffmpeg.probe(input_file)
    video_info = next(s for s in probe['streams'] if s['codec_type'] == 'video')
    fps_str = video_info.get('r_frame_rate', '25/1')
    num, den = map(int, fps_str.split('/'))
    return num / den

input_file = "testing/stefano_prores422_hq.mov"

# Create temporary WAV file
temp_audio = tempfile.NamedTemporaryFile(suffix='.wav', delete=False)
temp_audio.close()
extract_audio(input_file, temp_audio.name)

probe = ffmpeg.probe(input_file)
video_info = next(s for s in probe['streams'] if s['codec_type'] == 'video')
width = int(video_info['width'])
height = int(video_info['height'])
fps = get_video_fps(input_file)

process = (
    ffmpeg
    .input(input_file)
    .output('pipe:', format='rawvideo', pix_fmt='rgb24')
    .run_async(pipe_stdout=True)
)

pygame.init()
pygame.mixer.init(frequency=44100, size=-16, channels=2, buffer=4096)
clock = pygame.time.Clock()
screen = pygame.display.set_mode((width, height))

pygame.mixer.music.load(temp_audio.name)
pygame.mixer.music.play()

frame_count = 0
start_time = pygame.time.get_ticks()

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.mixer.music.stop()
            os.unlink(temp_audio.name)
            sys.exit()

    in_bytes = process.stdout.read(width * height * 3)
    if not in_bytes:
        break

    # Calculate timing for synchronization
    expected_frame_time = frame_count * (1000 / fps)
    actual_time = pygame.time.get_ticks() - start_time
    
    if actual_time < expected_frame_time:
        pygame.time.wait(int(expected_frame_time - actual_time))
    
    in_frame = (
        np.frombuffer(in_bytes, dtype="uint8")
        .reshape([height, width, 3])
    )
    out_frame = pygame.surfarray.make_surface(np.transpose(in_frame, (1, 0, 2)))
    screen.blit(out_frame, (0, 0))
    pygame.display.flip()
    
    frame_count += 1

pygame.mixer.music.stop()
process.wait()
pygame.quit()
os.unlink(temp_audio.name)


  


  I also tried using pygame mixer and a separate mp3 audio file, but that didn't work either. Any help on how to synch the sound while keeping the playback of both videos to 25 FPS would be greatly appreciated !!!

  


• How to render two videos with alpha channel in real time in pygame with synched audio ?

  21 décembre 2024, par Francesco Calderone

  I need to play two videos with synched sound in real-time with Pygame.
Pygame does not currently support video streams, so I am using a ffmpeg subprocess.
The first video is a prores422_hq. This is a background video with no alpha channel.
The second video is a prores4444 overlay video with an alpha channel, and it needs to be played in real-tim on top of the first video (with transparency).
All of this needs synched sound from the first base video only.

  


  I have tried many libraries, including pymovie pyav and opencv. The best result so far is to use a subprocess with ffmpeg.

  


  ffmpeg -i testing/stefano_prores422_hq.mov -stream_loop -1 -i testing/key_prores4444.mov -filter_complex "[1:v]format=rgba,colorchannelmixer=aa=1.0[overlay];[0:v][overlay]overlay" -f nut pipe:1 | ffplay -

  


  When running this in the terminal and playing with ffplay, everything is perfect, the overlay looks good, no dropped frames, and the sound is in synch.

  


  However, trying to feed that to pygame via a subprocess creates either video delays and drop frames or audio not in synch.

  


  EXAMPLE ONE :

  


  # SOUND IS NOT SYNCHED - sound is played via ffplay
import pygame
import subprocess
import numpy as np
import sys

def main():
    pygame.init()
    screen_width, screen_height = 1920, 1080
    screen = pygame.display.set_mode((screen_width, screen_height))
    pygame.display.set_caption("PyGame + FFmpeg Overlay with Audio")
    clock = pygame.time.Clock()

    # LAUNCH AUDIO-ONLY SUBPROCESS
    audio_cmd = [
        "ffplay",
        "-nodisp",          # no video window
        "-autoexit",        # exit when video ends
        "-loglevel", "quiet",
        "testing/stefano_prores422_hq.mov"
    ]
    audio_process = subprocess.Popen(audio_cmd)

    # LAUNCH VIDEO-OVERLAY SUBPROCESS
    ffmpeg_command = [
        "ffmpeg",
        "-re",                        # read at native frame rate
        "-i", "testing/stefano_prores422_hq.mov",
        "-stream_loop", "-1",         # loop alpha video
        "-i", "testing/key_prores4444.mov",
        "-filter_complex",
        "[1:v]format=rgba,colorchannelmixer=aa=1.0[overlay];"  # ensure alpha channel
        "[0:v][overlay]overlay",      # overlay second input onto first
        "-f", "rawvideo",             # output raw video
        "-pix_fmt", "rgba",           # RGBA format
        "pipe:1"                      # write to STDOUT
    ]
    video_process = subprocess.Popen(
        ffmpeg_command,
        stdout=subprocess.PIPE,
        stderr=subprocess.DEVNULL
    )
    frame_size = screen_width * screen_height * 4  # RGBA = 4 bytes/pixel
    running = True
    while running:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                running = False
                break

        raw_frame = video_process.stdout.read(frame_size)

        if len(raw_frame) < frame_size:
            running = False
            break
        # Convert raw bytes -> NumPy array -> PyGame surface
        frame_array = np.frombuffer(raw_frame, dtype=np.uint8)
        frame_array = frame_array.reshape((screen_height, screen_width, 4))
        frame_surface = pygame.image.frombuffer(frame_array.tobytes(), 
                                                (screen_width, screen_height), 
                                                "RGBA")
        screen.blit(frame_surface, (0, 0))
        pygame.display.flip()
        clock.tick(25)
    video_process.terminate()
    video_process.wait()
    audio_process.terminate()
    audio_process.wait()
    pygame.quit()
    sys.exit()

if __name__ == "__main__":
    main()



  


  EXAMPLE TWO

  


  # NO VIDEO OVERLAY - SOUND SYNCHED
import ffmpeg
import pygame
import sys
import numpy as np
import tempfile
import os

def extract_audio(input_file, output_file):
    """Extract audio from video file to temporary WAV file"""
    (
        ffmpeg
        .input(input_file)
        .output(output_file, acodec='pcm_s16le', ac=2, ar='44100')
        .overwrite_output()
        .run(capture_stdout=True, capture_stderr=True)
    )

def get_video_fps(input_file):
    probe = ffmpeg.probe(input_file)
    video_info = next(s for s in probe['streams'] if s['codec_type'] == 'video')
    fps_str = video_info.get('r_frame_rate', '25/1')
    num, den = map(int, fps_str.split('/'))
    return num / den

input_file = "testing/stefano_prores422_hq.mov"

# Create temporary WAV file
temp_audio = tempfile.NamedTemporaryFile(suffix='.wav', delete=False)
temp_audio.close()
extract_audio(input_file, temp_audio.name)

probe = ffmpeg.probe(input_file)
video_info = next(s for s in probe['streams'] if s['codec_type'] == 'video')
width = int(video_info['width'])
height = int(video_info['height'])
fps = get_video_fps(input_file)

process = (
    ffmpeg
    .input(input_file)
    .output('pipe:', format='rawvideo', pix_fmt='rgb24')
    .run_async(pipe_stdout=True)
)

pygame.init()
pygame.mixer.init(frequency=44100, size=-16, channels=2, buffer=4096)
clock = pygame.time.Clock()
screen = pygame.display.set_mode((width, height))

pygame.mixer.music.load(temp_audio.name)
pygame.mixer.music.play()

frame_count = 0
start_time = pygame.time.get_ticks()

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.mixer.music.stop()
            os.unlink(temp_audio.name)
            sys.exit()

    in_bytes = process.stdout.read(width * height * 3)
    if not in_bytes:
        break

    # Calculate timing for synchronization
    expected_frame_time = frame_count * (1000 / fps)
    actual_time = pygame.time.get_ticks() - start_time
    
    if actual_time < expected_frame_time:
        pygame.time.wait(int(expected_frame_time - actual_time))
    
    in_frame = (
        np.frombuffer(in_bytes, dtype="uint8")
        .reshape([height, width, 3])
    )
    out_frame = pygame.surfarray.make_surface(np.transpose(in_frame, (1, 0, 2)))
    screen.blit(out_frame, (0, 0))
    pygame.display.flip()
    
    frame_count += 1

pygame.mixer.music.stop()
process.wait()
pygame.quit()
os.unlink(temp_audio.name)


  


  I also tried using pygame mixer and a separate mp3 audio file, but that didn't work either. Any help on how to synch the sound while keeping the playback of both videos to 25 FPS would be greatly appreciated !!!