hyperion.ng/libsrc/grabber/v4l2/V4L2Grabber.cpp
Paulchen-Panther 657fe00211
Troubleshooting and ...
- More i18n
- Easy use of mutual exclusion in JsonAPI with QMutexLocker
- Smoothing type "linear" hidden in the WebUI, because there is currently only one
- Message forwarding implemented again
- For compatibility to home assistants and other remote controls, "activeEffects" and "activeLedColor" has been added to the JSON-RPC
- FlatBuffer clear now the Priority on disconnect
- The information "available V4L2 devices" is now only displayed if the device list is not empty
- LED device "PiBlaster" excluded from OSX build
2019-02-03 14:36:57 +01:00

966 lines
20 KiB
C++

#include <iostream>
#include <sstream>
#include <stdexcept>
#include <cstdio>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <linux/videodev2.h>
#include <QDirIterator>
#include <QFileInfo>
#include "grabber/V4L2Grabber.h"
#define CLEAR(x) memset(&(x), 0, sizeof(x))
V4L2Grabber::V4L2Grabber(const QString & device
, VideoStandard videoStandard
, PixelFormat pixelFormat
, int pixelDecimation
)
: Grabber("V4L2:"+device)
, _deviceName()
, _input(-1)
, _videoStandard(videoStandard)
, _ioMethod(IO_METHOD_MMAP)
, _fileDescriptor(-1)
, _buffers()
, _pixelFormat(pixelFormat)
, _pixelDecimation(-1)
, _lineLength(-1)
, _frameByteSize(-1)
, _noSignalCounterThreshold(40)
, _noSignalThresholdColor(ColorRgb{0,0,0})
, _signalDetectionEnabled(true)
, _noSignalDetected(false)
, _noSignalCounter(0)
, _x_frac_min(0.25)
, _y_frac_min(0.25)
, _x_frac_max(0.75)
, _y_frac_max(0.75)
, _streamNotifier(nullptr)
, _initialized(false)
, _deviceAutoDiscoverEnabled(false)
{
setPixelDecimation(pixelDecimation);
getV4Ldevices();
// init
setDeviceVideoStandard(device, videoStandard);
}
V4L2Grabber::~V4L2Grabber()
{
uninit();
}
void V4L2Grabber::uninit()
{
// stop if the grabber was not stopped
if (_initialized)
{
Debug(_log,"uninit grabber: %s", QSTRING_CSTR(_deviceName));
stop();
uninit_device();
close_device();
_initialized = false;
}
}
bool V4L2Grabber::init()
{
if (! _initialized)
{
getV4Ldevices();
QString v4lDevices_str;
// show list only once
if ( ! QString(QSTRING_CSTR(_deviceName)).startsWith("/dev/") )
{
for (auto& dev: _v4lDevices)
{
v4lDevices_str += "\t"+ dev.first + "\t" + dev.second + "\n";
}
if (!v4lDevices_str.isEmpty())
Info(_log, "available V4L2 devices:\n%s", QSTRING_CSTR(v4lDevices_str));
}
if ( _deviceName == "auto" )
{
_deviceAutoDiscoverEnabled = true;
_deviceName = "unknown";
Info( _log, "search for usable video devices" );
for (auto& dev: _v4lDevices)
{
_deviceName = dev.first;
if ( init() )
{
Info(_log, "found usable v4l2 device: %s (%s)",QSTRING_CSTR(dev.first), QSTRING_CSTR(dev.second));
_deviceAutoDiscoverEnabled = false;
return _initialized;
}
}
Info( _log, "no usable device found" );
}
else if ( ! _deviceName.startsWith("/dev/") )
{
for (auto& dev: _v4lDevices)
{
if ( _deviceName.toLower() == dev.second.toLower() )
{
_deviceName = dev.first;
Info(_log, "found v4l2 device with configured name: %s (%s)", QSTRING_CSTR(dev.second), QSTRING_CSTR(dev.first) );
break;
}
}
}
else
{
Info(_log, "%s v4l device: %s", (_deviceAutoDiscoverEnabled? "test" : "configured"), QSTRING_CSTR(_deviceName));
}
bool opened = false;
try
{
// do not init with unknown device
if(_deviceName != "unknown")
{
open_device();
opened = true;
init_device(_videoStandard, _input);
_initialized = true;
}
}
catch(std::exception& e)
{
if (opened)
{
uninit_device();
close_device();
}
ErrorIf( !_deviceAutoDiscoverEnabled, _log, "V4l2 init failed (%s)", e.what());
}
}
return _initialized;
}
void V4L2Grabber::getV4Ldevices()
{
QDirIterator it("/sys/class/video4linux/", QDirIterator::NoIteratorFlags);
while(it.hasNext())
{
//_v4lDevices
QString dev = it.next();
if (it.fileName().startsWith("video"))
{
QFile devNameFile(dev+"/name");
QString devName;
if ( devNameFile.exists())
{
devNameFile.open(QFile::ReadOnly);
devName = devNameFile.readLine();
devName = devName.trimmed();
devNameFile.close();
}
_v4lDevices.emplace("/dev/"+it.fileName(), devName);
}
}
}
void V4L2Grabber::setSignalThreshold(double redSignalThreshold, double greenSignalThreshold, double blueSignalThreshold, int noSignalCounterThreshold)
{
_noSignalThresholdColor.red = uint8_t(255*redSignalThreshold);
_noSignalThresholdColor.green = uint8_t(255*greenSignalThreshold);
_noSignalThresholdColor.blue = uint8_t(255*blueSignalThreshold);
_noSignalCounterThreshold = qMax(1, noSignalCounterThreshold);
Info(_log, "Signal threshold set to: {%d, %d, %d}", _noSignalThresholdColor.red, _noSignalThresholdColor.green, _noSignalThresholdColor.blue );
}
void V4L2Grabber::setSignalDetectionOffset(double horizontalMin, double verticalMin, double horizontalMax, double verticalMax)
{
// rainbow 16 stripes 0.47 0.2 0.49 0.8
// unicolor: 0.25 0.25 0.75 0.75
_x_frac_min = horizontalMin;
_y_frac_min = verticalMin;
_x_frac_max = horizontalMax;
_y_frac_max = verticalMax;
Info(_log, "Signal detection area set to: %f,%f x %f,%f", _x_frac_min, _y_frac_min, _x_frac_max, _y_frac_max );
}
QRectF V4L2Grabber::getSignalDetectionOffset()
{
return QRectF(_x_frac_min, _y_frac_min, _x_frac_max, _y_frac_max);
}
bool V4L2Grabber::start()
{
try
{
if (init() && _streamNotifier != nullptr && !_streamNotifier->isEnabled())
{
_streamNotifier->setEnabled(true);
start_capturing();
Info(_log, "Started");
return true;
}
}
catch(std::exception& e)
{
Error(_log, "start failed (%s)", e.what());
}
return false;
}
void V4L2Grabber::stop()
{
if (_streamNotifier != nullptr && _streamNotifier->isEnabled())
{
stop_capturing();
_streamNotifier->setEnabled(false);
Info(_log, "Stopped");
}
}
void V4L2Grabber::open_device()
{
struct stat st;
if (-1 == stat(QSTRING_CSTR(_deviceName), &st))
{
throw_errno_exception("Cannot identify '" + _deviceName + "'");
return;
}
if (!S_ISCHR(st.st_mode))
{
throw_exception("'" + _deviceName + "' is no device");
return;
}
_fileDescriptor = open(QSTRING_CSTR(_deviceName), O_RDWR | O_NONBLOCK, 0);
if (-1 == _fileDescriptor)
{
throw_errno_exception("Cannot open '" + _deviceName + "'");
return;
}
// create the notifier for when a new frame is available
_streamNotifier = new QSocketNotifier(_fileDescriptor, QSocketNotifier::Read);
_streamNotifier->setEnabled(false);
connect(_streamNotifier, SIGNAL(activated(int)), this, SLOT(read_frame()));
}
void V4L2Grabber::close_device()
{
if (-1 == close(_fileDescriptor))
{
throw_errno_exception("close");
return;
}
_fileDescriptor = -1;
if (_streamNotifier != nullptr)
{
delete _streamNotifier;
_streamNotifier = nullptr;
}
}
void V4L2Grabber::init_read(unsigned int buffer_size)
{
_buffers.resize(1);
_buffers[0].length = buffer_size;
_buffers[0].start = malloc(buffer_size);
if (!_buffers[0].start) {
throw_exception("Out of memory");
return;
}
}
void V4L2Grabber::init_mmap()
{
struct v4l2_requestbuffers req;
CLEAR(req);
req.count = 4;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;
if (-1 == xioctl(VIDIOC_REQBUFS, &req)) {
if (EINVAL == errno) {
throw_exception("'" + _deviceName + "' does not support memory mapping");
return;
} else {
throw_errno_exception("VIDIOC_REQBUFS");
return;
}
}
if (req.count < 2) {
throw_exception("Insufficient buffer memory on " + _deviceName);
return;
}
_buffers.resize(req.count);
for (size_t n_buffers = 0; n_buffers < req.count; ++n_buffers) {
struct v4l2_buffer buf;
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = n_buffers;
if (-1 == xioctl(VIDIOC_QUERYBUF, &buf))
{
throw_errno_exception("VIDIOC_QUERYBUF");
return;
}
_buffers[n_buffers].length = buf.length;
_buffers[n_buffers].start =
mmap(NULL /* start anywhere */,
buf.length,
PROT_READ | PROT_WRITE /* required */,
MAP_SHARED /* recommended */,
_fileDescriptor, buf.m.offset);
if (MAP_FAILED == _buffers[n_buffers].start)
{
throw_errno_exception("mmap");
return;
}
}
}
void V4L2Grabber::init_userp(unsigned int buffer_size)
{
struct v4l2_requestbuffers req;
CLEAR(req);
req.count = 4;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_USERPTR;
if (-1 == xioctl(VIDIOC_REQBUFS, &req)) {
if (EINVAL == errno)
{
throw_exception("'" + _deviceName + "' does not support user pointer");
return;
} else {
throw_errno_exception("VIDIOC_REQBUFS");
return;
}
}
_buffers.resize(4);
for (size_t n_buffers = 0; n_buffers < 4; ++n_buffers) {
_buffers[n_buffers].length = buffer_size;
_buffers[n_buffers].start = malloc(buffer_size);
if (!_buffers[n_buffers].start) {
throw_exception("Out of memory");
return;
}
}
}
void V4L2Grabber::init_device(VideoStandard videoStandard, int input)
{
struct v4l2_capability cap;
if (-1 == xioctl(VIDIOC_QUERYCAP, &cap))
{
if (EINVAL == errno) {
throw_exception("'" + _deviceName + "' is no V4L2 device");
return;
} else {
throw_errno_exception("VIDIOC_QUERYCAP");
return;
}
}
if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE))
{
throw_exception("'" + _deviceName + "' is no video capture device");
return;
}
switch (_ioMethod) {
case IO_METHOD_READ:
if (!(cap.capabilities & V4L2_CAP_READWRITE))
{
throw_exception("'" + _deviceName + "' does not support read i/o");
return;
}
break;
case IO_METHOD_MMAP:
case IO_METHOD_USERPTR:
if (!(cap.capabilities & V4L2_CAP_STREAMING))
{
throw_exception("'" + _deviceName + "' does not support streaming i/o");
return;
}
break;
}
/* Select video input, video standard and tune here. */
struct v4l2_cropcap cropcap;
CLEAR(cropcap);
cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (0 == xioctl(VIDIOC_CROPCAP, &cropcap)) {
struct v4l2_crop crop;
crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
crop.c = cropcap.defrect; /* reset to default */
if (-1 == xioctl(VIDIOC_S_CROP, &crop)) {
switch (errno) {
case EINVAL:
/* Cropping not supported. */
break;
default:
/* Errors ignored. */
break;
}
}
} else {
/* Errors ignored. */
}
// set input if needed
if (input >= 0)
{
if (-1 == xioctl(VIDIOC_S_INPUT, &input))
{
throw_errno_exception("VIDIOC_S_INPUT");
return;
}
}
// set the video standard if needed
switch (videoStandard)
{
case VIDEOSTANDARD_PAL:
{
v4l2_std_id std_id = V4L2_STD_PAL;
if (-1 == xioctl(VIDIOC_S_STD, &std_id))
{
throw_errno_exception("VIDIOC_S_STD");
return;
}
}
break;
case VIDEOSTANDARD_NTSC:
{
v4l2_std_id std_id = V4L2_STD_NTSC;
if (-1 == xioctl(VIDIOC_S_STD, &std_id))
{
throw_errno_exception("VIDIOC_S_STD");
return;
}
}
break;
case VIDEOSTANDARD_SECAM:
{
v4l2_std_id std_id = V4L2_STD_SECAM;
if (-1 == xioctl(VIDIOC_S_STD, &std_id))
{
throw_errno_exception("VIDIOC_S_STD");
return;
}
}
break;
case VIDEOSTANDARD_NO_CHANGE:
default:
// No change to device settings
break;
}
// get the current settings
struct v4l2_format fmt;
CLEAR(fmt);
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl(VIDIOC_G_FMT, &fmt))
{
throw_errno_exception("VIDIOC_G_FMT");
return;
}
// set the requested pixel format
switch (_pixelFormat)
{
case PIXELFORMAT_UYVY:
fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_UYVY;
break;
case PIXELFORMAT_YUYV:
fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
break;
case PIXELFORMAT_RGB32:
fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB32;
break;
case PIXELFORMAT_NO_CHANGE:
default:
// No change to device settings
break;
}
// TODO Does never accept own sizes? use always _imageResampler instead
/*
// calc the size based on pixelDecimation
fmt.fmt.pix.width = fmt.fmt.pix.width / _pixelDecimation;
fmt.fmt.pix.height = fmt.fmt.pix.height / _pixelDecimation;
// set the settings
if (-1 == xioctl(VIDIOC_S_FMT, &fmt))
{
throw_errno_exception("VIDIOC_S_FMT");
return;
}
// get the format settings again
// (the size may not have been accepted without an error)
if (-1 == xioctl(VIDIOC_G_FMT, &fmt))
{
throw_errno_exception("VIDIOC_G_FMT");
return;
}
*/
// set the line length
_lineLength = fmt.fmt.pix.bytesperline;
// store width & height
_width = fmt.fmt.pix.width;
_height = fmt.fmt.pix.height;
// display the used width and height
Debug(_log, "width=%d height=%d", _width, _height );
// check pixel format and frame size
switch (fmt.fmt.pix.pixelformat)
{
case V4L2_PIX_FMT_UYVY:
_pixelFormat = PIXELFORMAT_UYVY;
_frameByteSize = _width * _height * 2;
Debug(_log, "Pixel format=UYVY");
break;
case V4L2_PIX_FMT_YUYV:
_pixelFormat = PIXELFORMAT_YUYV;
_frameByteSize = _width * _height * 2;
Debug(_log, "Pixel format=YUYV");
break;
case V4L2_PIX_FMT_RGB32:
_pixelFormat = PIXELFORMAT_RGB32;
_frameByteSize = _width * _height * 4;
Debug(_log, "Pixel format=RGB32");
break;
default:
throw_exception("Only pixel formats UYVY, YUYV, and RGB32 are supported");
return;
}
switch (_ioMethod) {
case IO_METHOD_READ:
init_read(fmt.fmt.pix.sizeimage);
break;
case IO_METHOD_MMAP:
init_mmap();
break;
case IO_METHOD_USERPTR:
init_userp(fmt.fmt.pix.sizeimage);
break;
}
}
void V4L2Grabber::uninit_device()
{
switch (_ioMethod) {
case IO_METHOD_READ:
free(_buffers[0].start);
break;
case IO_METHOD_MMAP:
for (size_t i = 0; i < _buffers.size(); ++i)
if (-1 == munmap(_buffers[i].start, _buffers[i].length))
{
throw_errno_exception("munmap");
return;
}
break;
case IO_METHOD_USERPTR:
for (size_t i = 0; i < _buffers.size(); ++i)
free(_buffers[i].start);
break;
}
_buffers.resize(0);
}
void V4L2Grabber::start_capturing()
{
switch (_ioMethod) {
case IO_METHOD_READ:
/* Nothing to do. */
break;
case IO_METHOD_MMAP:
{
for (size_t i = 0; i < _buffers.size(); ++i) {
struct v4l2_buffer buf;
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = i;
if (-1 == xioctl(VIDIOC_QBUF, &buf))
{
throw_errno_exception("VIDIOC_QBUF");
return;
}
}
v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl(VIDIOC_STREAMON, &type))
{
throw_errno_exception("VIDIOC_STREAMON");
return;
}
break;
}
case IO_METHOD_USERPTR:
{
for (size_t i = 0; i < _buffers.size(); ++i) {
struct v4l2_buffer buf;
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_USERPTR;
buf.index = i;
buf.m.userptr = (unsigned long)_buffers[i].start;
buf.length = _buffers[i].length;
if (-1 == xioctl(VIDIOC_QBUF, &buf))
{
throw_errno_exception("VIDIOC_QBUF");
return;
}
}
v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl(VIDIOC_STREAMON, &type))
{
throw_errno_exception("VIDIOC_STREAMON");
return;
}
break;
}
}
}
void V4L2Grabber::stop_capturing()
{
enum v4l2_buf_type type;
switch (_ioMethod) {
case IO_METHOD_READ:
/* Nothing to do. */
break;
case IO_METHOD_MMAP:
case IO_METHOD_USERPTR:
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
ErrorIf((xioctl(VIDIOC_STREAMOFF, &type) == -1), _log, "VIDIOC_STREAMOFF error code %d, %s", errno, strerror(errno));
break;
}
}
int V4L2Grabber::read_frame()
{
bool rc = false;
try
{
struct v4l2_buffer buf;
switch (_ioMethod) {
case IO_METHOD_READ:
int size;
if ((size = read(_fileDescriptor, _buffers[0].start, _buffers[0].length)) == -1)
{
switch (errno)
{
case EAGAIN:
return 0;
case EIO:
/* Could ignore EIO, see spec. */
/* fall through */
default:
throw_errno_exception("read");
return 0;
}
}
rc = process_image(_buffers[0].start, size);
break;
case IO_METHOD_MMAP:
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
if (-1 == xioctl(VIDIOC_DQBUF, &buf))
{
switch (errno)
{
case EAGAIN:
return 0;
case EIO:
/* Could ignore EIO, see spec. */
/* fall through */
default:
throw_errno_exception("VIDIOC_DQBUF");
return 0;
}
}
assert(buf.index < _buffers.size());
rc = process_image(_buffers[buf.index].start, buf.bytesused);
if (-1 == xioctl(VIDIOC_QBUF, &buf))
{
throw_errno_exception("VIDIOC_QBUF");
return 0;
}
break;
case IO_METHOD_USERPTR:
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_USERPTR;
if (-1 == xioctl(VIDIOC_DQBUF, &buf))
{
switch (errno)
{
case EAGAIN:
return 0;
case EIO:
/* Could ignore EIO, see spec. */
/* fall through */
default:
throw_errno_exception("VIDIOC_DQBUF");
return 0;
}
}
for (size_t i = 0; i < _buffers.size(); ++i)
{
if (buf.m.userptr == (unsigned long)_buffers[i].start && buf.length == _buffers[i].length)
{
break;
}
}
rc = process_image((void *)buf.m.userptr, buf.bytesused);
if (-1 == xioctl(VIDIOC_QBUF, &buf))
{
throw_errno_exception("VIDIOC_QBUF");
return 0;
}
break;
}
}
catch (std::exception& e)
{
emit readError(e.what());
rc = false;
}
return rc ? 1 : 0;
}
bool V4L2Grabber::process_image(const void *p, int size)
{
// We do want a new frame...
if (size != _frameByteSize)
{
Error(_log, "Frame too small: %d != %d", size, _frameByteSize);
}
else
{
process_image(reinterpret_cast<const uint8_t *>(p));
return true;
}
return false;
}
void V4L2Grabber::process_image(const uint8_t * data)
{
Image<ColorRgb> image(0, 0);
_imageResampler.processImage(data, _width, _height, _lineLength, _pixelFormat, image);
if (_signalDetectionEnabled)
{
// check signal (only in center of the resulting image, because some grabbers have noise values along the borders)
bool noSignal = true;
// top left
unsigned xOffset = image.width() * _x_frac_min;
unsigned yOffset = image.height() * _y_frac_min;
// bottom right
unsigned xMax = image.width() * _x_frac_max;
unsigned yMax = image.height() * _y_frac_max;
for (unsigned x = xOffset; noSignal && x < xMax; ++x)
{
for (unsigned y = yOffset; noSignal && y < yMax; ++y)
{
noSignal &= (ColorRgb&)image(x, y) <= _noSignalThresholdColor;
}
}
if (noSignal)
{
++_noSignalCounter;
}
else
{
if (_noSignalCounter >= _noSignalCounterThreshold)
{
_noSignalDetected = true;
Info(_log, "Signal detected");
}
_noSignalCounter = 0;
}
if ( _noSignalCounter < _noSignalCounterThreshold)
{
emit newFrame(image);
}
else if (_noSignalCounter == _noSignalCounterThreshold)
{
_noSignalDetected = false;
Info(_log, "Signal lost");
}
}
else
{
emit newFrame(image);
}
}
int V4L2Grabber::xioctl(int request, void *arg)
{
int r;
do
{
r = ioctl(_fileDescriptor, request, arg);
}
while (-1 == r && EINTR == errno);
return r;
}
void V4L2Grabber::throw_exception(const QString & error)
{
Error(_log, "Throws error: %s", QSTRING_CSTR(error));
}
void V4L2Grabber::throw_errno_exception(const QString & error)
{
Error(_log, "Throws error nr: %s", QSTRING_CSTR(QString(error + " error code " + QString::number(errno) + ", " + strerror(errno))));
}
void V4L2Grabber::setSignalDetectionEnable(bool enable)
{
if(_signalDetectionEnabled != enable)
{
_signalDetectionEnabled = enable;
Info(_log, "Signal detection is now %s", enable ? "enabled" : "disabled");
}
}
bool V4L2Grabber::getSignalDetectionEnabled()
{
return _signalDetectionEnabled;
}
void V4L2Grabber::setPixelDecimation(int pixelDecimation)
{
if(_pixelDecimation != pixelDecimation)
{
_pixelDecimation = pixelDecimation;
_imageResampler.setHorizontalPixelDecimation(pixelDecimation);
_imageResampler.setVerticalPixelDecimation(pixelDecimation);
}
}
void V4L2Grabber::setDeviceVideoStandard(QString device, VideoStandard videoStandard)
{
if(_deviceName != device || _videoStandard != videoStandard)
{
// extract input of device
QChar input = device.at(device.size() - 1);
_input = input.isNumber() ? input.digitValue() : -1;
uninit();
_deviceName = device;
_videoStandard = videoStandard;
// start if init is a success
if(init())
start();
}
}