We’re really pleased to announce the very first preview release of the Picamera2 Python library, the replacement for the Picamera library deprecated during the release of Bullseye back in November.

If you’ve used any of the Raspberry Pi cameras you’re probably familiar with Picamera, an excellent Python library designed to provide easy access to imaging capabilities on Raspberry Pi. But you might also know that, with our recent move to more open and standard Linux APIs, the Picamera library — built on top of a proprietary Broadcom camera stack — isn’t going to be supported in the future.

The original Picamera library was third-party software, developed by Dave Jones and not worked on by us here at Raspberry Pi. However, the library proved immensely popular with our users, so we’ve undertaken to provide a replacement. Imaginatively named Picamera2, the new library is being developed in-house here in Cambridge by Raspberry Pi, and will eventually be an officially supported package.

So today we’re announcing a first preview release of Picamera2.

What do we mean by a preview release?

By preview release, we mean something that’s very much a work in progress. It has quite a lot of functionality already that you can try, but there are still some important things missing, and in some cases things that are not quite working as well as we might like. It’s also highly likely, in fact pretty certain, that a number of aspects of the functionality and of the public-facing APIs are going to change before we release the library more generally.

Among the features supported in today’s release:

• You can configure and start the camera, and receive multiple image streams.
• Picamera2 supports preview windows, either standalone or embedded within Qt applications.
• You can query and set camera parameters.
• You can capture full-resolution still images as JPEGs or PNGs.
• Or you can capture them as numpy arrays for feeding to image analysis applications.

However, there is a rather obvious missing feature, which is that we’re still working on video recording using the Raspberry Pi’s hardware h.264 encoder. If you want to record video from Python using Picamera2 that’s something you can’t do today, and it probably remains “a few weeks” away.

If you’re interested in taking a look at what is a very early release of the new Picamera2 library we’d be interested to hear how folks get on with it, and whether there is any useful functionality that we’ve overlooked, or that could be made easier to use.

What can I do with it?

The best explanation might be just to show a few snippets of code! The first example starts a preview window and then does a full-resolution JPEG capture:

from qt_gl_preview import *
from picamera2 import *
import time

picam2 = Picamera2()
preview = QtGlPreview(picam2)

preview_config = picam2.preview_configuration()
capture_config = picam2.still_configuration()
picam2.configure(preview_config)

picam2.start()
time.sleep(2)

picam2.switch_mode_and_capture_file(capture_config, "capture.jpg")

In this next example, we capture preview images and pass them to OpenCV to see if it can detect any faces in the image using a Haar cascade.

It then draws detection boxes around any faces it finds and again displays the image in a preview window:

#!/usr/bin/python3

import cv2

from null_preview import *
from picamera2 import *

# Grab images as numpy arrays and leave everything else to OpenCV.

face_detector = cv2.CascadeClassifier("/usr/local/lib/python3.9/dist-packages/cv2/data/haarcascade_frontalface_default.xml")
cv2.startWindowThread()

picam2 = Picamera2()
preview = NullPreview(picam2)
picam2.configure(picam2.preview_configuration(main={"size": (640, 480)}))
picam2.start()

while True:
    im = picam2.capture_array()

    grey = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)
    faces = face_detector.detectMultiScale(grey, 1.1, 5)

    for (x, y, w, h) in faces:
        cv2.rectangle(im, (x, y), (x + w, y + h), (0, 255, 0))

    cv2.imshow("Camera", im)

Beyond these two, we’ve created over twenty small example scripts to act as an informal tutorial, and to help folks explore what functionality is available in this preview release. In due course, and once the rate at which things are changing settles down, we’ll work to expand this information and add some more formal documentation and tutorials.

How do I try it?

You can find the preview version of Picamera2 on Github, and the repository README.md gives full installation instructions.

However, installation is not for the faint of heart. As Picamera2 is built on top of libcamera’s own Python bindings which are currently in a prototype phase, for the time being installation involves checking out a special Raspberry Pi-curated version of the libcamera library, and compiling it manually.

There is no way to install the preview version of Picamera2 via a package manager, or via other mechanisms. For now, you’ll have to build it from the source. If you don’t feel comfortable doing that, it’s probably better that you wait for a more stable version.

However, if you do take a look at the preview, once you’ve had a chance to look through the example code and maybe have a play with the library yourself, we’d very much appreciate hearing any useful suggestions. I’ll keep an eye on this page, and on discussions over on the camera forum so that I can try and answer any questions you might have around today’s release.