Another MJPEG server example, this time with 90/270 degree rotation

We perform the rotation by munging the exif header orientation. Browsers I've tried seem to support this! Signed-off-by: David Plowman <[email protected]>
raspberrypi · Apr 18, 2024 · adcefaa · adcefaa
1 parent 301eec8
commit adcefaa
Showing 1 changed file with 108 additions and 0 deletions.
diff --git a/examples/mjpeg_server_with_rotation.py b/examples/mjpeg_server_with_rotation.py
@@ -0,0 +1,108 @@
+#!/usr/bin/python3
+
+# This is the same as mjpeg_server_2.py, but allows 90 or 270 degree rotations.
+
+import io
+import logging
+import socketserver
+from http import server
+from threading import Condition
+
+import piexif
+
+from picamera2 import Picamera2
+from picamera2.encoders import MJPEGEncoder
+from picamera2.outputs import FileOutput
+
+ROTATION = 270  # Use 0, 90 or 270
+WIDTH = 640
+HEIGHT = 480
+
+rotation_header = bytes()
+if ROTATION:
+    WIDTH, HEIGHT = HEIGHT, WIDTH
+    code = 6 if ROTATION == 90 else 8
+    exif_bytes = piexif.dump({'0th': {piexif.ImageIFD.Orientation: code}})
+    exif_len = len(exif_bytes) + 2
+    rotation_header = bytes.fromhex('ffe1') + exif_len.to_bytes(2, 'big') + exif_bytes
+
+PAGE = f"""\
+<html>
+<head>
+<title>picamera2 MJPEG streaming demo</title>
+</head>
+<body>
+<h1>Picamera2 MJPEG Streaming Demo</h1>
+<img src="stream.mjpg" width="{WIDTH}" height="{HEIGHT}" />
+</body>
+</html>
+"""
+
+
+class StreamingOutput(io.BufferedIOBase):
+    def __init__(self):
+        self.frame = None
+        self.condition = Condition()
+
+    def write(self, buf):
+        with self.condition:
+            self.frame = buf[:2] + rotation_header + buf[2:]
+            self.condition.notify_all()
+
+
+class StreamingHandler(server.BaseHTTPRequestHandler):
+    def do_GET(self):
+        if self.path == '/':
+            self.send_response(301)
+            self.send_header('Location', '/index.html')
+            self.end_headers()
+        elif self.path == '/index.html':
+            content = PAGE.encode('utf-8')
+            self.send_response(200)
+            self.send_header('Content-Type', 'text/html')
+            self.send_header('Content-Length', len(content))
+            self.end_headers()
+            self.wfile.write(content)
+        elif self.path == '/stream.mjpg':
+            self.send_response(200)
+            self.send_header('Age', 0)
+            self.send_header('Cache-Control', 'no-cache, private')
+            self.send_header('Pragma', 'no-cache')
+            self.send_header('Content-Type', 'multipart/x-mixed-replace; boundary=FRAME')
+            self.end_headers()
+            try:
+                while True:
+                    with output.condition:
+                        output.condition.wait()
+                        frame = output.frame
+                    self.wfile.write(b'--FRAME\r\n')
+                    self.send_header('Content-Type', 'image/jpeg')
+                    self.send_header('Content-Length', len(frame))
+                    self.end_headers()
+                    self.wfile.write(frame)
+                    self.wfile.write(b'\r\n')
+            except Exception as e:
+                logging.warning(
+                    'Removed streaming client %s: %s',
+                    self.client_address, str(e))
+        else:
+            self.send_error(404)
+            self.end_headers()
+
+
+class StreamingServer(socketserver.ThreadingMixIn, server.HTTPServer):
+    allow_reuse_address = True
+    daemon_threads = True
+
+
+picam2 = Picamera2()
+picam2.configure(picam2.create_video_configuration(main={"size": (640, 480)}))
+output = StreamingOutput()
+picam2.start_recording(MJPEGEncoder(), FileOutput(output))
+
+try:
+    address = ('', 8000)
+    server = StreamingServer(address, StreamingHandler)
+    server.serve_forever()
+finally:
+    picam2.stop_recording()