dxcam 0.3.0

A Python high-performance screenshot library for Windows using Desktop Duplication API

DXcam

Fast Python Screen Capture for Windows - Updated 2026

import dxcam

with dxcam.create() as camera:
    frame = camera.grab()

Live API Docs: https://ra1nty.github.io/DXcam/

Introduction

DXcam is a high-performance python screenshot and capture library for Windows based on the Desktop Duplication API. It is designed for low-latency, high-FPS capture pipelines (including full-screen Direct3D applications).

Compared with common Python alternatives, DXcam focuses on:

• Higher capture throughput (240+fps on 1080p)
• Stable capture for full-screen exclusive Direct3D apps
• Better FPS pacing for continuous video capture
• Support DXGI / Windows Graphics Capture dual backend
• Seamless integration for AI Agent / Computer Vision use cases.

Installation

From PyPI (pip)

Minimal install:

pip install dxcam

Full feature: (includes OpenCV-based color conversion, WinRT capture backend support:):

pip install "dxcam[cv2,winrt]"

Notes:

• Official Windows wheels are built for CPython 3.10 to 3.14.
• Binary wheels include the Cython kernels used by processor backends.

From source

Please refer to CONTRIBUTING.

Contributing / Dev

Contributions are welcome! Development setup and contributor workflow are documented in CONTRIBUTING.md.

Usage

Each output (monitor) is associated with one DXCamera instance.

import dxcam
camera = dxcam.create()  # primary output on device 0

To specify backends:

camera = dxcam.create(
    backend="dxgi", # default Desktop Duplication backend
    processor_backend="cv2" # default OpenCV processor
)

Screenshot

frame = camera.grab()

grab() returns a numpy.ndarray. None if no new frame is available since the last capture (for backward compatibility); use camera.grab(new_frame_only=False) to make dxcam always return the latest frame.

Use copy=False (or camera.grab_view()) for a zero-copy view. This is faster, but the returned buffer can be overwritten by later captures.

To capture a region:

left, top = (1920 - 640) // 2, (1080 - 640) // 2
right, bottom = left + 640, top + 640
frame = camera.grab(region=(left, top, right, bottom)) # numpy.ndarray of size (640x640x3) -> (HXWXC)

Screen Capture

camera.start(region=(left, top, right, bottom), target_fps=60)
camera.is_capturing  # True
# ...
camera.stop()
camera.is_capturing  # False

Consume the Screen Capture Data

for _ in range(1000):
    frame = camera.get_latest_frame()  # blocks until a frame is available

The screen capture mode spins up a thread that polls newly rendered frames and stores them in an in-memory ring buffer. The blocking and video_mode behavior is designed for downstream video recording and machine learning workloads.

Useful variants:

• camera.get_latest_frame(with_timestamp=True) -> (frame, frame_timestamp) -> return frame timestamp
• camera.get_latest_frame_view() -> zero-copy view into the frame buffer
• camera.grab(copy=False) / camera.grab_view() -> zero-copy latest-frame snapshot

When start() capture is running, calling grab() reads from the in-memory ring buffer instead of directly polling DXGI.

Safely Releasing Resources

release() stops capture, frees buffers, and releases capture resources. After release(), the same instance cannot be reused.

camera = dxcam.create(output_idx=0, output_color="BGR")
camera.release()
# camera.start()  # raises RuntimeError

Equivalently you can use context manager:

with dxcam.create() as camera:
    frame = camera.grab()
# resource released automatically

Full API Docs: https://ra1nty.github.io/DXcam/

Advanced Usage and Remarks

Multiple monitors / GPUs

cam1 = dxcam.create(device_idx=0, output_idx=0)
cam2 = dxcam.create(device_idx=0, output_idx=1)
cam3 = dxcam.create(device_idx=1, output_idx=1)

img1 = cam1.grab()
img2 = cam2.grab()
img3 = cam3.grab()

Inspect available devices/outputs:

>>> import dxcam
>>> print(dxcam.device_info())
'Device[0]:<Device Name:NVIDIA GeForce RTX 3090 Dedicated VRAM:24348Mb VendorId:4318>\n'
>>> print(dxcam.output_info())
'Device[0] Output[0]: Res:(1920, 1080) Rot:0 Primary:True\nDevice[0] Output[1]: Res:(1920, 1080) Rot:0 Primary:False\n'

Output Format

Set output color mode when creating the camera:

dxcam.create(output_color="BGRA")

Supported modes: "RGB", "RGBA", "BGR", "BGRA", "GRAY".

Notes:

• Data is returned as numpy.ndarray.
• BGRA does not require OpenCV and is the leanest dependency path.
• RGB, BGR, RGBA, GRAY require conversion (cv2 or compiled numpy backend).

Frame Buffer

DXcam uses a fixed-size ring buffer in-memory. New frames overwrite old frames when full.

camera = dxcam.create(max_buffer_len=120)  # default is 8

Target FPS

DXcam uses high-resolution pacing with drift correction to run near target_fps.

camera.start(target_fps=120)  # default to 60, greater than 120 is resource heavy

On Python 3.11+, DXcam relies on Windows high-resolution timer behavior used by time.sleep(). On older versions, DXcam uses WinAPI waitable timers directly.

Frame Timestamp

Read the most recent frame timestamp (seconds):

camera.start(target_fps=60)
frame, ts = camera.get_latest_frame(with_timestamp=True)
camera.stop()

For backend="dxgi", this value comes from DXGI_OUTDUPL_FRAME_INFO.LastPresentTime. For backend="winrt", this value is derived from WinRT SystemRelativeTime.

Video Mode

With video_mode=True, DXcam fills the buffer at target FPS, reusing the previous frame if needed, even if no new frame is rendered.

import cv2
import dxcam

target_fps = 30
camera = dxcam.create(output_color="BGR")
camera.start(target_fps=target_fps, video_mode=True)

writer = cv2.VideoWriter(
    "video.mp4", cv2.VideoWriter_fourcc(*"mp4v"), target_fps, (1920, 1080)
)
for _ in range(600):
    writer.write(camera.get_latest_frame())

camera.stop()
writer.release()

Capture Backend

DXcam supports two capture backends:

• dxgi (default): Desktop Duplication API path with broad compatibility.
• winrt: Windows Graphics Capture path.

Use it like this:

camera = dxcam.create(backend="dxgi")
camera = dxcam.create(backend="winrt")

Guideline:

• If you need cursor rendering, use winrt.
• Start with dxgi for most workloads, especially one-shot grab.
• Try winrt if it performs better on your machine or fits your app constraints.

Processor Backend

DXcam capture backends (dxgi/winrt) first acquire a BGRA frame.
The processor backend then handles post-processing:

• optional rotation/cropping preparation
• color conversion to your output_color

Recommended backend choice:

• OpenCV installed: use cv2 (default)
• No OpenCV installed: use numpy (Cython kernels)

Use it like this:

camera = dxcam.create(processor_backend="cv2")
camera = dxcam.create(processor_backend="numpy")

Official Windows wheels already include the compiled NumPy kernels.

Only for source installs:

set DXCAM_BUILD_CYTHON=1
pip install -e .[cython] --no-build-isolation

If processor_backend="numpy" is selected but compiled kernels are unavailable, DXcam logs a warning and falls back to cv2 behavior. In that fallback path, install OpenCV for non-BGRA output modes.

Benchmarks

When using a similar logic (only capture newly rendered frames) running on a 240fps output, DXCam, python-mss, D3DShot benchmarked as follow:

	DXcam	python-mss	D3DShot
Average FPS	239.19 :checkered_flag:	75.87	118.36
Std Dev	1.25	0.5447	0.3224

The benchmark is across 5 runs, with a light-moderate usage on my PC (5900X + 3090; Chrome ~30tabs, VS Code opened, etc.), I used the Blur Buster UFO test to constantly render 240 fps on my monitor. DXcam captured almost every frame rendered. You will see some benchmarks online claiming 1000+fps capture while most of them is busy-spinning a for loop on a staled frame (no new frame rendered on screen in test scenario).

For Targeting FPS:

(Target)\(mean,std)	DXcam	python-mss	D3DShot
60fps	61.71, 0.26 :checkered_flag:	N/A	47.11, 1.33
30fps	30.08, 0.02 :checkered_flag:	N/A	21.24, 0.17

Work Referenced

OBS Studio - implementation ideas and references.

D3DShot : DXcam borrowed some ctypes header from the no-longer maintained D3DShot.