Capture Photos while Streaming

Question

At the moment, i have Pi Camera > Pi > Ethernet Cable > Pi > Display, and using the codes from, https://www.youtube.com/watch?v=r80dcfzClD4 i am able to stream video from one Pi to another.

What i was wondering, how would i need to change these codes to allow me to take photos while streaming? i did have a python script that allowed me to do this by pressing a button, if i can incorporate it somehow

Answer 1

You can stream raspivid output as RTSP stream using various software like vlc,ffmpeg, etc..

Here is the example VLC command:

raspivid -o - -t 9999999 -w 1280 -h 720 | cvlc -vvv stream:///dev/stdin --sout '#rtp{sdp=rtsp://:554/}' :demux=h264

After create a rtsp stream, you can save some screenshot using this rtsp stream

Here is the example FFMPEG command:

ffmpeg -i {RTSP_SOURCE} -ss 00:00:01 -f image2 -vframes 1 thumb.jpg

Answer 2

I am doing it with OpenCV. I am taking picture right from camera stream, but it is possible to capture picture from device too. My example:

import urllib.request
import cv2
import numpy as np    

def CaptureFrontCamera():
    _bytes = bytes()
    stream = urllib.request.urlopen('http://192.168.0.51/video.cgi?resolution=1920x1080')
    while True:
        _bytes += stream.read(1024)
        a = _bytes.find(b'\xff\xd8')
        b = _bytes.find(b'\xff\xd9')
        if a != -1 and b != -1:
            jpg = _bytes[a:b+2]
            _bytes = _bytes[b+2:]
            filename = '/home/pi/capture.jpeg'
            i = cv2.imdecode(np.fromstring(jpg, dtype=np.uint8), cv2.IMREAD_COLOR)
            cv2.imwrite(filename, i)
            return filename