def getH264V4l2(verbose=False):
    """Find all V4l2 cameras with H264 encoding, and returns a list of tuples with ..
    
    (device file, device name), e.g. ("/dev/video2", "HD Pro Webcam C920 (/dev/video2)")
    """
    import glob
    from subprocess import Popen, PIPE
    
    cams=[]

    for device in glob.glob("/sys/class/video4linux/*"):
        devname=device.split("/")[-1]
        devfile=os.path.join("/dev",devname)
        
        lis=("v4l2-ctl --list-formats -d "+devfile).split()

        p = Popen(lis, stdout=PIPE, stderr=PIPE)
        # p.communicate()
        # print(dir(p))
        # print(p.returncode)
        # print(p.stderr.read().decode("utf-8"))
        st = p.stdout.read().decode("utf-8")
        # print(st)
        
        if (st.lower().find("h264")>-1):
            namefile=os.path.join(device, "name")
            # print(namefile)
            f=open(namefile, "r"); name=f.read(); f.close()
            fullname = name.strip() + " ("+devname+")"
            cams.append((devfile, fullname))

    if (verbose):
        for cam in cams:
            print(cam)
        
    return cams