Member Avatar for blaze423

I was wondering if there is a way to record video from a USB webcam to a .avi file (including sound). I know how to view video and capture screenshots, but I'd like to be able to record a section of video. If there really isn't then is there a way to take a series of images and audio and compile them into a video file? The reason for this project is to make AI accessible video logs. Let me know.

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If you want true video+audio in one file from Python, treat it as two steps: capture both streams, then mux them. OpenCV can write an .avi video track, but it cannot add an audio track itself, so you need a tool like FFmpeg (or use PyAV if you want to stay in Python and handle both streams programmatically). (docs.opencv.org)

A simple, reliable workflow that builds on what and @Tech B discussed:

  • Record video with OpenCV, record audio with sounddevice, then merge with FFmpeg’s stream mapping. FFmpeg’s -map lets you pick video from input 0 and audio from input 1; -shortest trims the output to the shorter stream so you avoid frozen last frames. (ffmpeg.org)
# 1) Record ~10s of video
import cv2, time
cap = cv2.VideoCapture(0)
fps = 20.0
w = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH)); h = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
out = cv2.VideoWriter('cam.avi', cv2.VideoWriter_fourcc(*'XVID'), fps, (w, h))
t_end = time.time() + 10
while time.time() < t_end:
    ok, frame = cap.read()
    if not ok: break
    out.write(frame)
cap.release(); out.release()

# 2) Record ~10s of audio
import sounddevice as sd, soundfile as sf
sr = 48000
audio = sd.rec(int(sr*10), samplerate=sr, channels=1, dtype='int16')
sd.wait()
sf.write('mic.wav', audio, sr)

Then mux to a single AVI:

ffmpeg -i cam.avi -i mic.wav -c:v copy -c:a pcm_s16le -shortest out.avi

This copies the video as-is and encodes audio as PCM inside AVI; add -map 0:v -map 1:a if you have multiple streams. (ffmpeg.org)

Notes:

  • If you prefer an all-in-Python approach, PyAV (FFmpeg bindings) can write audio+video directly to AVI/MP4 without the extra mux step. (pyav.org)
  • sounddevice’s rec/wait API makes short mic captures straightforward; use blocking=True or sd.wait() to avoid truncation. (python-sounddevice.readthedocs.io)

Tip: Although .avi works (e.g., XVID+PCM), MP4/H.264+AAC is more portable if your “AI-accessible logs” will be shared widely.

Recommended Answers

All 9 Replies

Member Avatar for TrustyTony

Just google 'web camera python' and you find for example one HOWTO:
http://technobabbler.com/?p=22

Edited by TrustyTony because: n/a
Member Avatar for blaze423

Just google 'web camera python' and you find for example one HOWTO:
http://technobabbler.com/?p=22

Right, like I said I know how to capture an individual frame from the webcam and save it, but what I'm trying to do is record video and audio from the webcam. Is there a way to do this?

Member Avatar for marekbar218

I was wondering if there is a way to record video from a USB webcam to a .avi file (including sound). I know how to view video and capture screenshots, but I'd like to be able to record a section of video. If there really isn't then is there a way to take a series of images and audio and compile them into a video file? The reason for this project is to make AI accessible video logs. Let me know.

I would suggest to use Emgu CV or aForge NET to do this if you write in C# or openCV if you write in C++.
There's a lot of examples how to do this on their websites. also you can use my code from:
http://napiszpr.webd.pl/mb/content/view/74/84/

Member Avatar for richieking

does python got a module for that?

Member Avatar for amysmith28

I was wondering if there is a way to record video from a USB webcam to a .avi file (including sound). I know how to view video and capture screenshots, but I'd like to be able to record a section of video. If there really isn't then is there a way to take a series of images and audio and compile them into a video file? The reason for this project is to make AI accessible video logs. Let me know.

Yeah, you can record video from USB webcam and save the video to AVI format file with some program, which can help you capture video and audio file from webcam. The audio can be recorded from any source, including microphone, line-in, or speakers.
And the program can also help you record any actions on screen, so you can record images and audio into a video. I always in this way. lol

Member Avatar for Tech B

I'm not sure about python itself doing it, but the way I would approach it would be to use an external program to do the actual video encoding. You could call it from python after you saved as many image files you wanted with your method of grabbing the images.

Using MEncoder Ubuntu:

sudo apt-get install mencoder
mencoder -ovc help

They have a windows version too I believe. You could use os.popen() or os.system() to run it via python.

Member Avatar for ashely97

Actually, there are many kinds of programs available on market can help you record webcam video. I like to use screen recorder, which can not only record video and audio streams from your webcam with high quality, but also can save the streams on your computer for latter playback. I often use it record msn webcam video when I was making video calls with my friends.

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