I am using two Kinect v2 in one application with OpenNI and here is the source code:

OpenNI::initialize();
openni::Array<DeviceInfo> mDeviceInfo;
OpenNI::enumerateDevices(&mDeviceInfo);
Device mDevice1;
Device mDevice2;

/*if (mDeviceInfo.getSize() != 2) {
    cout << "Wrong number of Kinects" << endl;
    return -1;
}*/

mDevice1.open(mDeviceInfo[0].getUri());
mDevice2.open(mDeviceInfo[1].getUri());

but it seems that doesn't work well because of loss of packets:

[Info] [Freenect2Impl] enumerating devices...
[Info] [Freenect2Impl] 8 usb devices connected
[Info] [Freenect2Impl] found valid Kinect v2 @105:2 with serial 0196534
[Info] [Freenect2Impl] found valid Kinect v2 @161:2 with serial 0197047
[Info] [Freenect2Impl] found 2 devices
[Info] [Freenect2Impl] enumerating devices...
[Info] [Freenect2Impl] 8 usb devices connected
[Info] [Freenect2Impl] found valid Kinect v2 @105:2 with serial 0196534
[Info] [Freenect2Impl] found valid Kinect v2 @161:2 with serial 0197047
[Info] [Freenect2Impl] found 2 devices
[Info] [Freenect2Impl] enumerating devices...
[Info] [Freenect2Impl] 8 usb devices connected
[Info] [Freenect2Impl] found valid Kinect v2 @105:2 with serial 0196534
[Info] [Freenect2Impl] found valid Kinect v2 @161:2 with serial 0197047
[Info] [Freenect2Impl] found 2 devices
[Info] [Freenect2DeviceImpl] opening...
[Info] [Freenect2DeviceImpl] opened
[Info] [Freenect2DeviceImpl] starting...
[Info] [Freenect2DeviceImpl] submitting rgb transfers...
[Info] [Freenect2DeviceImpl] submitting depth transfers...
[Info] [Freenect2DeviceImpl] started
[Info] [DepthPacketStreamParser] 2 packets were lost
[Info] [DepthPacketStreamParser] 4 packets were lost
[Info] [DepthPacketStreamParser] 4 packets were lost
[Info] [TurboJpegRgbPacketProcessor] avg. time: 13.2382ms -> ~75.5389Hz
[Info] [DepthPacketStreamParser] 5 packets were lost
[Info] [OpenGLDepthPacketProcessor] avg. time: 23.6746ms -> ~42.2394Hz
[Info] [DepthPacketStreamParser] 4 packets were lost
[Info] [DepthPacketStreamParser] 3 packets were lost
[Info] [DepthPacketStreamParser] 82 packets were lost
[Info] [TurboJpegRgbPacketProcessor] avg. time: 13.4984ms -> ~74.0827Hz
[Info] [OpenGLDepthPacketProcessor] avg. time: 26.3897ms -> ~37.8935Hz
[Info] [DepthPacketStreamParser] 17 packets were lost
[Info] [DepthPacketStreamParser] 5 packets were lost
[Info] [TurboJpegRgbPacketProcessor] avg. time: 13.8107ms -> ~72.4074Hz
[Info] [DepthPacketStreamParser] 14 packets were lost
[Info] [OpenGLDepthPacketProcessor] avg. time: 28.8671ms -> ~34.6415Hz

So are there other good solutions to get Kinects serial for device opening?

Dear Christian,

I testet 2 Kinects (attached to different USB-controllers) and tried to get Protonect running.
Therefore I replaced in Protonect.cpp
in the section where the device is initialized:
handle = libusb_open_device_with_vid_pid(NULL, vid, pid);
by
handle = libusb_open_device_with_vid_pid_num(NULL, vid, pid, num_wanted);
having
libusb_device_handle* libusb_open_device_with_vid_pid_num(libusb_context _ctx, uint16_t vendor_id, uint16_t product_id, int num_wanted)
{
struct libusb_device *_devs;
struct libusb_device *found = NULL;
struct libusb_device *dev;
struct libusb_device_handle *handle = NULL;
size_t i = 0;
int r;
int num = 0;
if (libusb_get_device_list(ctx, &devs) < 0)
return NULL;

while ((dev = devs[i++]) != NULL) {
struct libusb_device_descriptor desc;
r = libusb_get_device_descriptor(dev, &desc);
if (r < 0)
goto out;
if (desc.idVendor == vendor_id && desc.idProduct == product_id) {
if(num == num_wanted){
found = dev;
break;
}
else{
++num;
}
}
}

if (found) {
r = libusb_open(found, &handle);
if (r < 0)
handle = NULL;
}

out:
libusb_free_device_list(devs, 1);
return handle;
}

I am able to choose which Kinect I want to run from the commandline now (e.g. ./Protonect 0 vs. ./Protonect 1)
This works when running each Kinect one after another - but not when one Kinect is already runnig. Then I get the following error for the second "start":

steppo@pitoti:protonect/bin ‹opengl_depth_processor*›$ sudo ./Protonect 1
[sudo] password for steppo:
Using libusbx v1.0.17.10852

Opening device 045E:02C4...

Reading device descriptor:
length: 18
device class: 239
S/N: 4
VID:PID: 045E:02C4
bcdDevice: 0100
iMan:iProd:iSer: 1:2:4
nb confs: 1
speed: 5000 Mbit/s (USB SuperSpeed)
active configuration: 1, err: 0
Claiming interface 0...

Claiming interface 1...
running kinect...
Control transfer 1 - set isoch delay
Control transfer 2 - set sel u1/u2

Setting interface alt setting...
Setting stream status: Disable
Control transfer 3 - enable u1
Control transfer 4 - enable u2
Control transfer 5 - set feature 768
Setting sensor status: Disable
Kinect init done

iso max_packet_size: 33792
speed: 5000 Mbit/s (USB SuperSpeed)
running kinect...
Setting sensor status: Enable

Cmd seq 0 func 0x02 (0)
Cmd sent, 20 bytes sent
Cmd response seq 0 func 0x02 (0)
Cmd response success, 512 bytes received
Received cmd data 0x02 (0), length: 512
Cmd response seq 0 func 0x02 (0)
Cmd response success, 16 bytes received
Cmd response completed
Response complete for cmd 0x02 (0)
dumping 512 bytes of raw data from command KCMD_READ_DATA1:
0x0000: 01 00 01 00 5a 0b 00 00 00 00 00 00 00 00 00 00 ....Z...........
0x0010: 03 00 02 00 47 0f 00 00 00 00 00 00 00 00 00 00 ....G...........
0x0020: 03 00 02 00 47 0f 00 00 00 00 00 00 00 00 00 00 ....G...........
0x0030: 03 00 02 00 47 0f 00 00 00 00 00 00 00 00 00 00 ....G...........
0x0040: 01 00 01 00 5a 0b 00 00 00 00 00 00 00 00 00 00 ....Z...........
0x0050: 03 00 02 00 47 0f 00 00 00 00 00 00 00 00 00 00 ....G...........
0x0060: 03 00 02 00 47 0f 00 00 00 00 00 00 00 00 00 00 ....G...........
0x0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x00a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x00b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x00c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x00d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x00e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x00f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0170: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x01a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x01b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x01c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x01d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x01e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x01f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................

Cmd seq 1 func 0x14 (0)
Cmd sent, 20 bytes sent
Cmd response seq 1 func 0x14 (0)
Cmd response success, 92 bytes received
Received cmd data 0x14 (0), length: 92
Cmd response seq 1 func 0x14 (0)
Cmd response success, 16 bytes received
Cmd response completed
Response complete for cmd 0x14 (0)
dumping 92 bytes of raw data from command KCMD_READ_VERSIONS:
0x0000: 00 00 12 00 00 00 00 00 01 00 00 00 43 c1 1f 41 ............C..A
0x0010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0020: 0a 21 33 55 c2 00 17 20 00 08 00 00 10 00 00 00 .!3U... ........
0x0030: 00 01 00 00 00 10 00 00 00 00 80 00 01 00 00 00 ................
0x0040: 31 33 00 00 00 08 07 0d 47 48 59 30 35 34 2e 31 13......GHY054.1
0x0050: 58 00 00 00 00 00 00 00 07 00 00 00 X...........

Cmd seq 2 func 0x22 (0x1)
Cmd sent, 24 bytes sent
Cmd response seq 2 func 0x22 (0x1)
Cmd response success, 128 bytes received
Received cmd data 0x22 (0x1), length: 128
Cmd response seq 2 func 0x22 (0x1)
Cmd response success, 16 bytes received
Cmd response completed
Response complete for cmd 0x22 (0x1)
dumping 128 bytes of raw data from command KCMD_READ_DATA_PAGE 0x01:
0x0000: 31 00 31 00 30 00 33 00 35 00 36 00 35 00 33 00 1.1.0.3.5.6.5.3.
0x0010: 34 00 34 00 34 00 37 00 00 00 00 00 00 00 00 00 4.4.4.7.........
0x0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................

Cmd seq 3 func 0x22 (0x3)
Cmd sent, 24 bytes sent
Cmd response seq 3 func 0x22 (0x3)
libusbx: error [submit_bulk_transfer] submiturb failed error -1 errno=12
Cmd response error: -1
Error in response for 0x22 cmd (0x3)
Error in cmd protocol 0x22 (0x3)

Do you have any Idea whats going wrong there?
Maybe this is still to early, but I am looking forward to get 2 or even more Kinects running on a single workstation.

Kind regards,
Stephan

Dear Christian

I am testing to use two kinect v2 in one machine.
I am working with ubuntu 14.04.1
I install compile libfreenect2 without trouble.
I personalise in an other file the codde of Protonect.cpp like this :

bool protonect_shutdown = false;

void sigint_handler(int s)
{
protonect_shutdown = true;
}

inline void frame_deleter(libfreenect2::Frame* ptr)
{
ptr=nullptr;
}

struct device_t2
{

std::shared_ptr<libfreenect2::Freenect2Device> _device;
std::unique_ptr<libfreenect2::SyncMultiFrameListener> _listener;


cv::Mat _bgr;
cv::Mat _ir;
cv::Mat _depth;

device_t2(libfreenect2::Freenect2Device* ptr):
    _device(ptr,[](libfreenect2::Freenect2Device* ptr){ptr = nullptr;}),
    _listener(new libfreenect2::SyncMultiFrameListener(libfreenect2::Frame::Color | libfreenect2::Frame::Ir | libfreenect2::Frame::Depth)),

    {}



    void init()
    {
        if(this->_all_in)
        {
            this->_device->setColorFrameListener(this->_listener.get());
            this->_device->setIrAndDepthFrameListener(this->_listener.get());
        }
        else
        {
            if(this->_type & libfreenect2::Frame::Color)
            {
                this->_device->setColorFrameListener(this->_listener.get());
                this->_is_rgb = true;
            }

            if((this->_type & libfreenect2::Frame::Depth) || (this->_type & libfreenect2::Frame::Ir))
            {
                this->_device->setIrAndDepthFrameListener(this->_listener.get());

                if(this->_type & libfreenect2::Frame::Depth)
                    this->_is_depth = true;

                if(this->_type & libfreenect2::Frame::Ir)
                    this->_is_ir = true;

            }
        }
    }

    void start()
    {
        this->_device->start();
    }

    void stop()
    {
        this->_device->stop();
    }

    void close()
    {
        this->_device->close();
    }

    void grab_raw()
    {
        libfreenect2::FrameMap nodes;

        this->_listener->waitForNewFrame(nodes);


            std::shared_ptr<libfreenect2::Frame> bgr(nodes[libfreenect2::Frame::Color],frame_deleter);
            std::shared_ptr<libfreenect2::Frame> ir(nodes[libfreenect2::Frame::Ir],frame_deleter);
            std::shared_ptr<libfreenect2::Frame> depth(nodes[libfreenect2::Frame::Depth],frame_deleter);

            this->_bgr = cv::Mat(bgr->height,bgr->width,CV_8UC3,bgr->data).clone();
            this->_ir = cv::Mat(ir->height,ir->width,CV_32FC1,ir->data).clone();
            this->_depth = cv::Mat(depth->height,depth->width,CV_32FC1,depth->data).clone();


        this->_listener->release(nodes);
    }

    void grab_rescale()
    {
        this->grab_raw();

            this->_ir/=20000.f;


            this->_depth/=4500.f;
    }

};

int protonect2(const int& argc,char**& argv)
{
std::size_t id(0);

if(argc==2)
    id = atoi(argv[1]);

glfwInit();

libfreenect2::Freenect2 freenect2;

std::unique_ptr<device_t2> dev(new device_t2(freenect2.openDevice(id)));

if(dev->_device == 0)
{
  std::cout << "no device connected or failure opening the default one!" << std::endl;
  return -1;
}

signal(SIGINT,sigint_handler);
protonect_shutdown = false;


dev->init();


dev->start();

std::cout << "device serial: " << dev->_device->getSerialNumber() << std::endl;
std::cout << "device firmware: " << dev->_device->getFirmwareVersion() << std::endl;



while(!protonect_shutdown)
{

    dev->grab_rescale();

    cv::imshow("rgb",dev->_bgr);
    cv::imshow("ir", dev->_ir);
    cv::imshow("depth", dev->_depth);



  int key = cv::waitKey(1);
  protonect_shutdown = protonect_shutdown || (key > 0 && ((key & 0xFF) == 27)); // shutdown on escape

}

dev->stop();
dev->close();

return 0;

}

int protonect3(const int& argc,char**& argv)
{
// std::size_t id(0);

// if(argc==2)
// id = atoi(argv[1]);

glfwInit();

libfreenect2::Freenect2 freenect2;

std::unique_ptr<device_t2> dev(new device_t2(freenect2.openDevice(0)));
std::unique_ptr<device_t2> dev2(new device_t2(freenect2.openDevice(1)));

if(dev->_device == 0)
{
  std::cout << "no device connected or failure opening the default one!" << std::endl;
  return -1;
}

if(dev2->_device == 0)
{
  std::cout << "no device connected or failure opening the default one!" << std::endl;
  return -1;
}

signal(SIGINT,sigint_handler);
protonect_shutdown = false;


dev->init();
dev2->init();

dev->start();
dev2->start();

std::cout << "device serial: " << dev->_device->getSerialNumber() << std::endl;
std::cout << "device firmware: " << dev->_device->getFirmwareVersion() << std::endl;

std::cout << "device2 serial: " << dev2->_device->getSerialNumber() << std::endl;
std::cout << "device2 firmware: " << dev2->_device->getFirmwareVersion() << std::endl;


while(!protonect_shutdown)
{

    dev->grab_rescale();
    dev2->grab_rescale();

    cv::imshow("rgb",dev->_bgr);
    cv::imshow("ir", dev->_ir);
    cv::imshow("depth", dev->_depth);

    cv::imshow("rgb2",dev2->_bgr);
    cv::imshow("ir2", dev2->_ir);
    cv::imshow("depth2", dev2->_depth);


  int key = cv::waitKey(1);
  protonect_shutdown = protonect_shutdown || (key > 0 && ((key & 0xFF) == 27)); // shutdown on escape

}


dev->stop();
dev->close();

dev2->stop();
dev2->close();

return 0;

}

int main(int argc, char *argv[])
{

// return protonect2(argc,argv);

    return protonect3(argc,argv);

}

When I use the function protonect2 I am able to select and use the anyone of my two device, and it work well.
When I use the function protonect3 I obtain the following message :

[Freenect2Impl] enumerating devices...
[Freenect2Impl] 20 usb devices connected
[Freenect2Impl] found valid Kinect v2 @4:5 with serial 508080742542
[Freenect2Impl] found valid Kinect v2 @4:7 with serial 503075141942
[Freenect2Impl] found 2 devices
[Freenect2DeviceImpl] opening...
[Freenect2DeviceImpl] opened
[Freenect2DeviceImpl] opening...
[UsbControl::setConfiguration(set)] failed! libusb error -99: LIBUSB_ERROR_OTHER
[Freenect2DeviceImpl] closing...
[Freenect2DeviceImpl] deallocating usb transfer pools...
[Freenect2DeviceImpl] closing usb device...
[Freenect2DeviceImpl] closed
[Freenect2DeviceImpl] failed to open Kinect v2 @4:7!
no device connected or failure opening the default one!
[Freenect2DeviceImpl] closing...
[Freenect2DeviceImpl] releasing usb interfaces...
[Freenect2DeviceImpl] deallocating usb transfer pools...
[Freenect2DeviceImpl] closing usb device...
[Freenect2DeviceImpl] closed

It seem there is a trouble during the usb configuration time.
I have compile and install the libusb use by libfreenect2 on my system.
I also read #7 and modify the /etc/grub file without any results.

Have you any idea about what's wrong ?

Best regards

Julian