Recording video in Raspberry Pi - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Raspberry Pi camera recording code?

Consider this Python code snippet using the picamera library to record a video for 5 seconds. What will be the output?

Raspberry Pi

import time
from picamera import PiCamera

camera = PiCamera()
camera.start_recording('test_video.h264')
time.sleep(5)
camera.stop_recording()
print('Recording complete')

A No output

B SyntaxError

C RuntimeError: Camera not found

D Recording complete

💡 Hint

Think about what the print statement does after recording stops.

The code records a video for 5 seconds and then prints 'Recording complete'. No errors occur if the camera is connected properly.

🧠 Conceptual

intermediate

Which parameter controls the video resolution in PiCamera?

In the picamera library, which parameter sets the resolution of the recorded video?

A camera.resolution

B camera.framerate

C camera.brightness

D camera.contrast

💡 Hint

Resolution means width and height of the video.

The camera.resolution property sets the width and height of the video frames.

🔧 Debug

advanced

Why does this Raspberry Pi video recording code raise an error?

Look at this code snippet. It raises an error when run. What is the cause?

Raspberry Pi

from picamera import PiCamera
import time

camera = PiCamera()
camera.start_recording('video.h264')
camera.wait_recording(5)
camera.stop_recording()
print('Done')

A time module is not imported

B start_recording requires a file object, not a filename string

C wait_recording is not a method of PiCamera

D stop_recording must be called before wait_recording

💡 Hint

Check the official PiCamera documentation for method names.

The method wait_recording does not exist in PiCamera. The correct method to pause recording is time.sleep().

📝 Syntax

advanced

Which option correctly sets up a 10-second video recording with PiCamera?

Choose the code snippet that correctly records a 10-second video using PiCamera.

A

import time
from picamera import PiCamera
camera = PiCamera()
camera.record('vid.h264', 10)
camera.stop_recording()

B

import time
from picamera import PiCamera
camera = PiCamera()
camera.start_recording('vid.h264')
time.sleep(10)
camera.stop_recording()

C

from picamera import PiCamera
camera = PiCamera()
camera.start_recording('vid.h264')
camera.wait(10)
camera.stop_recording()

D

import time
from picamera import PiCamera
camera = PiCamera()
camera.start_recording('vid.h264')
time.wait(10)
camera.stop_recording()

💡 Hint

Remember to use time.sleep() to pause the program.

Option B uses the correct method start_recording, then pauses with time.sleep(10), and stops recording properly.

🚀 Application

expert

How to save a video in MP4 format using Raspberry Pi camera?

You want to record a video and save it directly as an MP4 file using the Raspberry Pi camera. Which approach is correct?

A Record video as H264 and then use <code>ffmpeg</code> to convert it to MP4 after recording

B Use <code>camera.start_recording('video.mp4')</code> and PiCamera saves MP4 automatically

C Set <code>camera.format = 'mp4'</code> before recording to save directly as MP4

D PiCamera cannot record video; use USB webcam instead

💡 Hint

Think about the default video format PiCamera records and how to convert it.

PiCamera records video in H264 format. To get MP4, you must convert the file using tools like ffmpeg after recording.