More updates to the examples

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>

Author: davidplowman

examples/capture_average.py

@@ -7,11 +7,12 @@
 import numpy as np
 from PIL import Image
 
-from picamera2 import Picamera2, Preview
+from picamera2 import MappedArray, Picamera2, Preview
 
 picam2 = Picamera2()
 picam2.start_preview(Preview.NULL)
-capture_config = picam2.create_still_configuration()
+# Buffer count of 2 will reduce frame drops (default is 1 otherwise)
+capture_config = picam2.create_still_configuration(buffer_count=2)
 picam2.configure(capture_config)
 
 picam2.start()
@@ -25,12 +26,15 @@
 imgs = 20  # Capture 20 images to average
 sumv = None
 for _ in range(imgs):
-    if sumv is None:
-        sumv = np.longdouble(picam2.capture_array())
-        img = Image.fromarray(np.uint8(sumv))
-        img.save("original.tif")
-    else:
-        sumv += np.longdouble(picam2.capture_array())
+    with picam2.captured_request() as request:
+        # Using MappedArray saves an array copy
+        with MappedArray(request, 'main') as m:
+            if sumv is None:
+                sumv = np.longdouble(m.array)
+                img = Image.fromarray(np.uint8(m.array))
+                img.save("original.tif")
+            else:
+                sumv += m.array
 
 img = Image.fromarray(np.uint8(sumv / imgs))
 img.save("averaged.tif")

examples/capture_dng_to_buffer.py

@@ -1,5 +1,7 @@
 #!/usr/bin/python3
 
+# Capture a DNG to a BytesIO.
+
 import io
 import time
 

examples/capture_mjpeg.py

@@ -4,6 +4,11 @@
 from picamera2 import Picamera2
 from picamera2.encoders import JpegEncoder
 
+# This is using the software JPEG encoder. On lower powered devices, the
+# MJPEGEncoder would be better as it uses the hardware encoder. See
+# capture_mjpeg_v4l2.py.
+
+
 picam2 = Picamera2()
 video_config = picam2.create_video_configuration(main={"size": (1920, 1080)})
 picam2.configure(video_config)

examples/capture_mjpeg_timestamp.py

@@ -4,6 +4,11 @@
 from picamera2 import Picamera2
 from picamera2.encoders import JpegEncoder
 
+# This is using the software JPEG encoder. On lower powered devices, the
+# MJPEGEncoder would be better as it uses the hardware encoder. See
+# capture_mjpeg_v4l2.py.
+
+
 picam2 = Picamera2()
 video_config = picam2.create_video_configuration(main={"size": (1920, 1080)})
 picam2.configure(video_config)

examples/capture_motion.py

@@ -1,5 +1,9 @@
 #!/usr/bin/python3
 
+# This example writes unformatted H.264 bitstream using the FileOutput. Mostly
+# we would now recommend using the PyavOutput to write mp4 files directly. See
+# capture_motion_improved.py.
+
 import time
 
 import numpy as np

examples/capture_motion_improved.py

@@ -0,0 +1,42 @@
+#!/usr/bin/python3
+
+import time
+
+import numpy as np
+
+from picamera2 import Picamera2
+from picamera2.encoders import H264Encoder
+from picamera2.outputs import PyavOutput
+
+lsize = (320, 240)
+picam2 = Picamera2()
+main = {"size": (1280, 720), "format": "RGB888"}
+lores = {"size": lsize, "format": "YUV420"}
+video_config = picam2.create_video_configuration(main, lores=lores)
+picam2.configure(video_config)
+encoder = H264Encoder(bitrate=1000000)
+picam2.start()
+
+w, h = lsize
+prev = None
+encoding = False
+ltime = 0
+
+while True:
+    cur = picam2.capture_array("lores")[:h, :w]
+    if prev is not None:
+        # Measure pixels differences between current and
+        # previous frame
+        mse = np.square(np.subtract(cur, prev)).mean()
+        if mse > 7:
+            if not encoding:
+                encoder.output = PyavOutput(f"{int(time.time())}.mp4")
+                picam2.start_encoder(encoder)
+                encoding = True
+                print("New Motion", mse)
+            ltime = time.time()
+        else:
+            if encoding and time.time() - ltime > 2.0:
+                picam2.stop_encoder()
+                encoding = False
+    prev = cur

examples/capture_stream_udp.py

@@ -1,5 +1,9 @@
 #!/usr/bin/python3
 
+# Send an H.264 bitstream over a UDP socket to a client. Mostly we would
+# recommend using PyavOutput so that you can send more widely supported
+# formats. See capture_stream_udp_improved.py.
+
 import socket
 import time
 

examples/capture_stream_udp_improved.py

@@ -0,0 +1,21 @@
+#!/usr/bin/python3
+
+# Send an MPEG2 transport stream over a socket using PyavOutput.
+
+import socket
+import time
+
+from picamera2 import Picamera2
+from picamera2.encoders import H264Encoder
+from picamera2.outputs import PyavOutput
+
+picam2 = Picamera2()
+video_config = picam2.create_video_configuration({"size": (1280, 720)})
+picam2.configure(video_config)
+encoder = H264Encoder(1000000)
+
+with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as sock:
+    sock.connect(("REMOTEIP", 10001))
+    picam2.start_recording(encoder, PyavOutput(f"pipe:{sock.fileno()}", format="mpegts"))  # noqa
+    time.sleep(20)
+    picam2.stop_recording()

examples/capture_video.py

@@ -4,6 +4,10 @@
 from picamera2 import Picamera2
 from picamera2.encoders import H264Encoder
 
+# This example saves an unformatted H.264 file. Mostly we would recommend
+# using the PyavOutput so that an mp4 file could be saved directly instead.
+
+
 picam2 = Picamera2()
 video_config = picam2.create_video_configuration()
 picam2.configure(video_config)

examples/easy_capture.py

@@ -1,5 +1,9 @@
 #!/usr/bin/python3
 
+# This is the most high level way to capture images and save them. Howwever,
+# the API gives you less control over the camera system so we would recommend
+# it only to folks with the simplest use-cases.
+
 from picamera2 import Picamera2
 
 picam2 = Picamera2()