Requires FFmpeg for primary recording. Install: choco install ffmpeg (Windows), brew install ffmpeg (macOS), apt install ffmpeg (Linux). Python fallback available if FFmpeg is not installed (no audio/cursor).

Screen Recording Skill

Record the actual screen — full desktop, a specific region, or a named window — to MP4 video with optional audio and cursor capture.

What this skill does

• Screen recording — capture what's actually on screen (primary purpose)
• Region/window recording — capture a specific area or application window
• Audio capture — record system audio alongside video
• Synthetic video generation — create animated demo videos programmatically (secondary)

---

Quick Start

Record full screen for 30 seconds

import platform, subprocess, shutil, signal, os

def record_screen(output="recording.mp4", duration=30, fps=30, audio=False):
    system = platform.system()
    cmd = ["ffmpeg"]

    if system == "Windows":
        if audio:
            cmd += ["-f", "dshow", "-i", "audio=Stereo Mix"]
        cmd += ["-f", "gdigrab", "-framerate", str(fps), "-draw_mouse", "1",
                "-i", "desktop"]
    elif system == "Darwin":
        devices = "0" if not audio else "0:1"
        cmd += ["-f", "avfoundation", "-framerate", str(fps),
                "-capture_cursor", "1", "-i", devices]
    else:  # Linux
        if audio:
            cmd += ["-f", "pulse", "-i", "default"]
        display = os.environ.get("DISPLAY", ":0.0")
        cmd += ["-f", "x11grab", "-framerate", str(fps), "-draw_mouse", "1",
                "-i", display]

    cmd += ["-c:v", "libx264", "-preset", "ultrafast", "-crf", "23",
            "-pix_fmt", "yuv420p"]
    if audio:
        cmd += ["-c:a", "aac", "-b:a", "128k"]
    if duration:
        cmd += ["-t", str(duration)]
    cmd += [output, "-y"]

    print(f"Recording → {output}")
    proc = subprocess.Popen(cmd, stderr=subprocess.PIPE)
    try:
        proc.wait()
    except KeyboardInterrupt:
        proc.send_signal(signal.SIGINT)
        proc.wait()
    print(f"Saved: {output} ({os.path.getsize(output):,} bytes)")
    return output

record_screen("recording.mp4", duration=30)

---

Decision Tree

User wants a video
│
├─ Record what's actually on screen?
│  ├─ FFmpeg installed? → Approach 1: FFmpeg (RECOMMENDED)
│  └─ No FFmpeg?       → Approach 2: Python fallback (mss + OpenCV)
│
└─ Create a synthetic animated demo/presentation?
   └─ YES → Approach 3: Programmatic generation (Pillow + MoviePy)

---

Approach 1: FFmpeg Screen Recording (RECOMMENDED)

FFmpeg uses platform-native capture APIs for fast, high-quality recording with audio and cursor support.

Read references/ffmpeg-recording.md for the full platform reference including window capture, audio device detection, and quality tuning.

Platform-specific input formats

Platform	Input Format	Cursor	Audio	Region
Windows	gdigrab	-draw_mouse 1	-f dshow -i audio="Stereo Mix"	-offset_x/-offset_y/-video_size
macOS	avfoundation	-capture_cursor 1	Device index "0:1"	-vf crop=w:h:x:y
Linux X11	x11grab	-draw_mouse 1	-f pulse -i default	-video_size WxH -i :0.0+X,Y
Linux Wayland	wf-recorder	Default	-a flag	-g "x,y wxh"

Full screen recording

Windows:

ffmpeg -f gdigrab -framerate 30 -draw_mouse 1 -i desktop -c:v libx264 -preset ultrafast -crf 23 -pix_fmt yuv420p -t 30 recording.mp4 -y

macOS:

ffmpeg -f avfoundation -framerate 30 -capture_cursor 1 -i "0" -c:v libx264 -preset ultrafast -crf 23 -pix_fmt yuv420p -t 30 recording.mp4 -y

Linux (X11):

ffmpeg -f x11grab -framerate 30 -draw_mouse 1 -i :0.0 -c:v libx264 -preset ultrafast -crf 23 -pix_fmt yuv420p -t 30 recording.mp4 -y

Region recording

# Record a specific area: (x=100, y=200, width=800, height=600)
region = (100, 200, 800, 600)

if system == "Windows":
    cmd += ["-offset_x", "100", "-offset_y", "200", "-video_size", "800x600", "-i", "desktop"]
elif system == "Darwin":
    cmd += ["-i", "0", "-vf", "crop=800:600:100:200"]  # crop after capture
else:  # Linux
    cmd += ["-video_size", "800x600", "-i", ":0.0+100,200"]

Window recording

Windows — by window title:

ffmpeg -f gdigrab -framerate 30 -i title="My App" -c:v libx264 -preset ultrafast recording.mp4 -y

macOS/Linux — get window bounds, then record as region. See references/ffmpeg-recording.md for platform-specific window geometry detection.

Audio capture

Audio device names vary per system. Detect available devices:

import subprocess, platform

system = platform.system()
if system == "Windows":
    # Lists DirectShow audio devices
    subprocess.run(["ffmpeg", "-list_devices", "true", "-f", "dshow", "-i", "dummy"])
elif system == "Darwin":
    # Lists AVFoundation devices (screens + audio)
    subprocess.run(["ffmpeg", "-f", "avfoundation", "-list_devices", "true", "-i", ""])
else:
    # PulseAudio sources
    subprocess.run(["pactl", "list", "short", "sources"])

Windows note: "Stereo Mix" must be enabled in Sound Settings → Recording tab. Right-click → Show Disabled Devices → Enable "Stereo Mix".

Stopping the recording

• Duration-based: Use -t SECONDS in the FFmpeg command
• Manual stop: Send SIGINT (Ctrl+C) to the FFmpeg process
• From Python: proc.send_signal(signal.SIGINT) then proc.wait()

---

Approach 2: Python Fallback (No FFmpeg)

When FFmpeg is not available, use mss for screenshots and cv2.VideoWriter to assemble them.

Read references/python-fallback.md for the full working template.

pip install mss opencv-python numpy

Basic capture loop

import mss, cv2, numpy as np, time

def record_screen_python(output="recording.mp4", duration=30, fps=20, region=None):
    with mss.mss() as sct:
        if region:
            x, y, w, h = region
            area = {"left": x, "top": y, "width": w, "height": h}
        else:
            mon = sct.monitors[1]
            area = {"left": mon["left"], "top": mon["top"],
                    "width": mon["width"], "height": mon["height"]}

        fourcc = cv2.VideoWriter_fourcc(*"mp4v")
        writer = cv2.VideoWriter(output, fourcc, fps, (area["width"], area["height"]))
        interval = 1.0 / fps
        start = time.time()

        while time.time() - start < duration:
            t0 = time.time()
            frame = np.array(sct.grab(area))[:, :, :3]
            writer.write(frame)
            elapsed = time.time() - t0
            if elapsed < interval:
                time.sleep(interval - elapsed)

        writer.release()
        print(f"Saved: {output}")

Limitations

• No audio — mss captures pixels only
• No cursor — cursor is not included in screenshots
• Lower FPS — typically 15-25 fps depending on resolution
• Larger files — mp4v codec is less efficient than H.264

---

Approach 3: Synthetic Video Generation

For creating animated demo videos, product showcases, or presentations without recording the real screen.

Read references/programmatic-generation.md for the full implementation guide.

Stack: Pillow (frame drawing) → MoviePy (video assembly) → pyttsx3 (TTS narration)

pip install "moviepy>=2.0" pillow pyttsx3

Key pattern:

from moviepy import VideoClip, AudioFileClip
from PIL import Image, ImageDraw
import numpy as np

def make_frame(t):
    img = Image.new('RGB', (1280, 720), (12, 12, 32))
    draw = ImageDraw.Draw(img)
    draw.text((100, 300), f"Frame at t={t:.1f}s", fill=(255, 255, 255))
    return np.array(img)

clip = VideoClip(make_frame, duration=10)
clip.write_videofile("demo.mp4", fps=24, logger=None)

---

Post-Processing (FFmpeg)

# Compress for sharing
ffmpeg -i recording.mp4 -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k compressed.mp4

# Trim (start at 5s, keep 30s)
ffmpeg -i recording.mp4 -ss 00:00:05 -t 00:00:30 -c copy trimmed.mp4

# Convert to GIF (for docs/chat)
ffmpeg -i recording.mp4 -vf "fps=12,scale=960:-1:flags=lanczos" -loop 0 demo.gif

# Add text overlay
ffmpeg -i recording.mp4 -vf "drawtext=text='Demo':fontcolor=white:fontsize=24:x=20:y=20" overlay.mp4

# Extract audio
ffmpeg -i recording.mp4 -vn -c:a mp3 audio.mp3

# Concatenate clips
# Create concat.txt: file 'clip1.mp4' \n file 'clip2.mp4'
ffmpeg -f concat -safe 0 -i concat.txt -c copy combined.mp4

---

Installation

FFmpeg (required for Approach 1)

Platform	Command
Windows	choco install ffmpeg or winget install FFmpeg or download from ffmpeg.org
macOS	brew install ffmpeg
Ubuntu/Debian	sudo apt install ffmpeg
Arch	sudo pacman -S ffmpeg

Verify: ffmpeg -version

Python packages

# For Approach 2 (Python fallback)
pip install mss opencv-python numpy

# For Approach 3 (synthetic video generation)
pip install "moviepy>=2.0" pillow pyttsx3

# On Linux, for TTS in Approach 3:
# sudo apt install espeak-ng

Wayland (Linux)

If on Wayland (echo $WAYLAND_DISPLAY returns a value), install wf-recorder:

sudo apt install wf-recorder    # Ubuntu
sudo pacman -S wf-recorder      # Arch

---

Common Pitfalls

Problem	Solution
FFmpeg not found	Install FFmpeg and ensure it's on PATH
Windows: no audio device	Enable "Stereo Mix" in Sound Settings → Recording → Show Disabled Devices
macOS: permission denied	Grant Screen Recording permission: System Settings → Privacy → Screen Recording
Linux: x11grab fails on Wayland	Use wf-recorder instead (see Wayland section)
Linux: no audio with x11grab	Install PulseAudio: sudo apt install pulseaudio
Black/empty video	Check DISPLAY variable on Linux (echo $DISPLAY), permissions on macOS
Recording too large	Re-encode: ffmpeg -i big.mp4 -crf 28 -preset slow small.mp4
Python fallback: low FPS	Reduce capture resolution or target FPS
Python fallback: no cursor	Known limitation — use FFmpeg approach for cursor capture
MoviePy import error	Use from moviepy import VideoClip (v2 syntax), install moviepy>=2.0

---

Reference Files

• references/ffmpeg-recording.md — Full FFmpeg command reference per platform, audio devices, window capture, quality tuning
• references/python-fallback.md — Complete mss + OpenCV recording template with performance tips
• references/programmatic-generation.md — Pillow + MoviePy synthetic video generation (animated demos)
• references/design-patterns.md — UI components and animation patterns for synthetic videos