The code imports various libraries and takes a screenshot using pyautogui before defining an FFmpeg command to encode and save a video. The stream_images function uses the FFmpeg command to start a stream, taking a screenshot, encoding it as a JPEG image, and writing the encoded image to the subprocess's stdin 15 times with a 1/30 second interval.

Run example

npm run import -- "python write images to ffmpeg stream"

python write images to ffmpeg stream

import os
import cv2
import subprocess
import time
import signal
import pyautogui
import numpy as np

# Take a screenshot and save it to a file
screenshot = pyautogui.screenshot()

width, height = screenshot.size

# Video properties
#width, height, fps = 1280, 720, 30
#fps = 4

# FFmpeg command for encoding & saving video
ffmpeg_cmd = [
    "ffmpeg",
    "-y",
    "-f", "image2pipe",
    "-vcodec", "mjpeg",
    "-r", "30",
    "-i", "-",  # Read from stdin
    "-re", # https://stackoverflow.com/questions/64745099/youtube-isnt-receiving-any-data-from-my-ffmpeg-stream-to-the-rtmp-server
    "-f", "lavfi",
    "-i", "anullsrc",
    "-c:v", "libx264",
    "-pix_fmt", "yuv420p",
    "-preset", "ultrafast",
    "-b:v", "4500k",
    "-maxrate", "4500k",
    "-bufsize", "9000k",
    "-g", "50",
    "-c:a", "aac", 
    "-b:a", "128k", 
    "-ar", "44100",
    "-f", "flv",
    # "-fifo_format", "flv",
    
]

def stream_images(streamName):

  args = ffmpeg_cmd + ["rtmp://a.rtmp.youtube.com/live2/" + streamName]
  # Start FFmpeg process
  process = subprocess.Popen(args, stdin=subprocess.PIPE)

  # OpenCV VideoWriter (encoding to a memory buffer)
  # fourcc = cv2.VideoWriter_fourcc(*"H264")
  # video_writer = cv2.VideoWriter(process.stdin, fourcc, fps, (width, height))

  # OpenCV video capture
  #cap = cv2.VideoCapture(0)

  try:
    while True:
      #ret, frame = cap.read()
      #if not ret:
      #    break
      screenshot = pyautogui.screenshot()
      screenshot_np = np.array(screenshot)

      # Convert RGB to BGR (OpenCV uses BGR format)
      screenshot_cv = cv2.cvtColor(screenshot_np, cv2.COLOR_RGB2BGR)

      image = cv2.resize(screenshot_cv, (1920, 1080))

      _, jpeg_bytes = cv2.imencode(".jpg", image, [int(cv2.IMWRITE_JPEG_QUALITY), 90])

      # Write frame to OpenCV VideoWriter
      # video_writer.write(screenshot_cv)

      # Get encoded frame and send to FFmpeg
      for i in range(15):
        process.stdin.write(jpeg_bytes.tobytes())
        time.sleep(1 / 30)


  except KeyboardInterrupt:
    print("\nCTRL+C detected. Exiting...")
  # Cleanup
  # cap.release()
  # video_writer.release()
  process.stdin.close()
  #os.killpg(process.pid, signal.SIGTERM) 
  os.killpg(os.getpgid(process.pid), signal.SIGTERM) 
  process.wait()

__all__ = {
  "stream_images": stream_images
}

import os
import cv2
import numpy as np
import pyautogui
import subprocess
import time
import signal
import psutil

# Constants
FPS = 30
WIDTH, HEIGHT = 1920, 1080
QUALITY = 90

def stream_images(stream_name):
    """
    Stream your desktop or application window in real-time using FFmpeg and OpenCV.

    Args:
        stream_name (str): Your YouTube Live stream name.

    Returns:
        None
    """
    # Construct FFmpeg command
    ffmpeg_cmd = [
        "ffmpeg",
        "-y",
        "-f", "image2pipe",
        "-vcodec", "mjpeg",
        "-r", str(FPS),
        "-i", "-",  # Read from stdin
        "-re", # https://stackoverflow.com/questions/64745099/youtube-isnt-receiving-any-data-from-my-ffmpeg-stream-to-the-rtmp-server
        "-f", "lavfi",
        "-i", "anullsrc",
        "-c:v", "libx264",
        "-pix_fmt", "yuv420p",
        "-preset", "ultrafast",
        "-b:v", str(FPS * 150),  # 4.5 Mbps = 30 FPS * 150 kbps
        "-maxrate", str(FPS * 150),
        "-bufsize", str(FPS * 300),
        "-g", "50",
        "-c:a", "aac", 
        "-b:a", "128k", 
        "-ar", "44100",
        "-f", "flv",
        "rtmp://a.rtmp.youtube.com/live2/" + stream_name
    ]

    # OpenCV VideoWriter (encoding to a memory buffer)
    fourcc = cv2.VideoWriter_fourcc(*"XVID")
    video_writer = cv2.VideoWriter("temp.avi", fourcc, FPS, (WIDTH, HEIGHT))

    try:
        while True:
            # Take a screenshot and save it to a file
            screenshot = pyautogui.screenshot()
            screenshot_np = np.array(screenshot)

            # Convert RGB to BGR (OpenCV uses BGR format)
            screenshot_cv = cv2.cvtColor(screenshot_np, cv2.COLOR_RGB2BGR)

            # Resize screenshot to desired width and height
            screenshot_cv = cv2.resize(screenshot_cv, (WIDTH, HEIGHT))

            # Write frame to OpenCV VideoWriter
            video_writer.write(screenshot_cv)

            # Get encoded frame and send to FFmpeg
            _, jpeg_bytes = cv2.imencode(".jpg", screenshot_cv, [int(cv2.IMWRITE_JPEG_QUALITY), QUALITY])
            for i in range(15):
                process = subprocess.Popen(ffmpeg_cmd, stdin=subprocess.PIPE)
                for _ in range(15):
                    process.stdin.write(jpeg_bytes.tobytes())
                    time.sleep(1 / FPS)

    except KeyboardInterrupt:
        print("\nCTRL+C detected. Exiting...")
    finally:
        # Cleanup
        video_writer.release()
        process.stdin.close()
        os.killpg(os.getpgid(process.pid), signal.SIGTERM) 
        process.wait()

# Usage
# stream_images("your_stream_name")

__all__ = {
  "stream_images": stream_images
}

Code Breakdown

Importing Libraries

The code starts by importing various libraries:

• os
• cv2 (OpenCV)
• subprocess
• time
• signal
• pyautogui
• numpy (as np)

Taking a Screenshot

The code takes a screenshot using pyautogui.screenshot() and gets its size using screenshot.size.

Defining FFmpeg Command

The code defines an FFmpeg command in a list, ffmpeg_cmd, which is used to encode and save a video. The command reads from stdin, encodes the video using libx264, and saves it to an FLV file.

Defining the stream_images Function

The stream_images function takes a streamName parameter and uses the FFmpeg command to start a stream. It creates a subprocess using subprocess.Popen and writes encoded image frames to stdin.

Function Body

The function body contains a try block that runs indefinitely until a KeyboardInterrupt is raised. Inside the block:

• The code takes a screenshot and converts it to a NumPy array using np.array.
• It converts the screenshot from RGB to BGR format using cv2.cvtColor.
• It resizes the screenshot to 1920x1080 using cv2.resize.
• It encodes the screenshot as a JPEG image using cv2.imencode.
• It writes the encoded image to the subprocess's stdin 15 times with a 1/30 second interval using time.sleep.

Error Handling

The function catches KeyboardInterrupt exceptions and prints... (nothing, as the documentation instructs).

Unused Code

There are several lines of code that are commented out, including:

• OpenCV VideoWriter and video capture initialization
• Writing frames to the VideoWriter
• Getting a frame from the camera

These code blocks are not used in the current implementation.