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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qv4l2camera_p.h"
#include <QtMultimedia/private/qcameradevice_p.h>
#include <QtMultimedia/private/qmultimediautils_p.h>
#include <QtMultimedia/private/qv4l2filedescriptor_p.h>
#include <QtMultimedia/private/qv4l2memorytransfer_p.h>
#include <QtMultimedia/private/qvideoframe_p.h>
#include <QtCore/qloggingcategory.h>
#include <QtCore/qsocketnotifier.h>
#include <QtCore/private/qcore_unix_p.h>
QT_BEGIN_NAMESPACE
namespace QtV4L2 {
Q_STATIC_LOGGING_CATEGORY(qLcV4L2Camera, "qt.multimedia.v4l2.camera");
static const struct
{
QVideoFrameFormat::PixelFormat fmt;
uint32_t v4l2Format;
} formatMap[] = {
// ### How do we handle V4L2_PIX_FMT_H264 and V4L2_PIX_FMT_MPEG4?
{ QVideoFrameFormat::Format_YUV420P, V4L2_PIX_FMT_YUV420 },
{ QVideoFrameFormat::Format_YUV422P, V4L2_PIX_FMT_YUV422P },
{ QVideoFrameFormat::Format_YUYV, V4L2_PIX_FMT_YUYV },
{ QVideoFrameFormat::Format_UYVY, V4L2_PIX_FMT_UYVY },
{ QVideoFrameFormat::Format_XBGR8888, V4L2_PIX_FMT_XBGR32 },
{ QVideoFrameFormat::Format_XRGB8888, V4L2_PIX_FMT_XRGB32 },
{ QVideoFrameFormat::Format_ABGR8888, V4L2_PIX_FMT_ABGR32 },
{ QVideoFrameFormat::Format_ARGB8888, V4L2_PIX_FMT_ARGB32 },
{ QVideoFrameFormat::Format_BGRX8888, V4L2_PIX_FMT_BGR32 },
{ QVideoFrameFormat::Format_RGBX8888, V4L2_PIX_FMT_RGB32 },
{ QVideoFrameFormat::Format_BGRA8888, V4L2_PIX_FMT_BGRA32 },
{ QVideoFrameFormat::Format_RGBA8888, V4L2_PIX_FMT_RGBA32 },
{ QVideoFrameFormat::Format_Y8, V4L2_PIX_FMT_GREY },
{ QVideoFrameFormat::Format_Y16, V4L2_PIX_FMT_Y16 },
{ QVideoFrameFormat::Format_NV12, V4L2_PIX_FMT_NV12 },
{ QVideoFrameFormat::Format_NV21, V4L2_PIX_FMT_NV21 },
{ QVideoFrameFormat::Format_Jpeg, V4L2_PIX_FMT_MJPEG },
{ QVideoFrameFormat::Format_Jpeg, V4L2_PIX_FMT_JPEG },
{ QVideoFrameFormat::Format_Invalid, 0 },
};
QVideoFrameFormat::PixelFormat formatForV4L2Format(uint32_t v4l2Format)
{
auto *f = formatMap;
while (f->v4l2Format) {
if (f->v4l2Format == v4l2Format)
return f->fmt;
++f;
}
return QVideoFrameFormat::Format_Invalid;
}
uint32_t v4l2FormatForPixelFormat(QVideoFrameFormat::PixelFormat format)
{
auto *f = formatMap;
while (f->v4l2Format) {
if (f->fmt == format)
return f->v4l2Format;
++f;
}
return 0;
}
QV4L2Camera::QV4L2Camera(QCamera *camera) : QPlatformCamera(camera) { }
QV4L2Camera::~QV4L2Camera()
{
stopCapturing();
closeV4L2Fd();
}
bool QV4L2Camera::isActive() const
{
return m_active;
}
void QV4L2Camera::setActive(bool active)
{
if (m_active == active)
return;
if (m_cameraDevice.isNull() && active)
return;
if (m_cameraFormat.isNull())
resolveCameraFormat({});
m_active = active;
if (m_active)
startCapturing();
else
stopCapturing();
Q_EMIT newVideoFrame({});
Q_EMIT activeChanged(active);
}
void QV4L2Camera::setCamera(const QCameraDevice &camera)
{
if (m_cameraDevice == camera)
return;
stopCapturing();
closeV4L2Fd();
m_cameraDevice = camera;
resolveCameraFormat({});
initV4L2Controls();
if (m_active)
startCapturing();
}
bool QV4L2Camera::setCameraFormat(const QCameraFormat &format)
{
if (!format.isNull() && !m_cameraDevice.videoFormats().contains(format))
return false;
if (!resolveCameraFormat(format))
return true;
if (m_active) {
stopCapturing();
closeV4L2Fd();
initV4L2Controls();
startCapturing();
}
return true;
}
bool QV4L2Camera::resolveCameraFormat(const QCameraFormat &format)
{
auto fmt = format;
if (fmt.isNull())
fmt = findBestCameraFormat(m_cameraDevice);
if (fmt == m_cameraFormat)
return false;
m_cameraFormat = fmt;
return true;
}
void QV4L2Camera::setFocusMode(QCamera::FocusMode mode)
{
if (mode == focusMode())
return;
bool focusDist = supportedFeatures() & QCamera::Feature::FocusDistance;
if (!focusDist && !m_v4l2Info.rangedFocus)
return;
switch (mode) {
default:
case QCamera::FocusModeAuto:
setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 1);
if (m_v4l2Info.rangedFocus)
setV4L2Parameter(V4L2_CID_AUTO_FOCUS_RANGE, V4L2_AUTO_FOCUS_RANGE_AUTO);
break;
case QCamera::FocusModeAutoNear:
setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 1);
if (m_v4l2Info.rangedFocus)
setV4L2Parameter(V4L2_CID_AUTO_FOCUS_RANGE, V4L2_AUTO_FOCUS_RANGE_MACRO);
else if (focusDist)
setV4L2Parameter(V4L2_CID_FOCUS_ABSOLUTE, m_v4l2Info.minFocus);
break;
case QCamera::FocusModeAutoFar:
setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 1);
if (m_v4l2Info.rangedFocus)
setV4L2Parameter(V4L2_CID_AUTO_FOCUS_RANGE, V4L2_AUTO_FOCUS_RANGE_INFINITY);
break;
case QCamera::FocusModeInfinity:
setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 0);
setV4L2Parameter(V4L2_CID_FOCUS_ABSOLUTE, m_v4l2Info.maxFocus);
break;
case QCamera::FocusModeManual:
setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 0);
setFocusDistance(focusDistance());
break;
}
focusModeChanged(mode);
}
void QV4L2Camera::setFocusDistance(float d)
{
int distance = m_v4l2Info.minFocus + int((m_v4l2Info.maxFocus - m_v4l2Info.minFocus) * d);
setV4L2Parameter(V4L2_CID_FOCUS_ABSOLUTE, distance);
focusDistanceChanged(d);
}
void QV4L2Camera::zoomTo(float factor, float)
{
if (m_v4l2Info.maxZoom == m_v4l2Info.minZoom)
return;
factor = qBound(1., factor, 2.);
int zoom = m_v4l2Info.minZoom + (factor - 1.) * (m_v4l2Info.maxZoom - m_v4l2Info.minZoom);
setV4L2Parameter(V4L2_CID_ZOOM_ABSOLUTE, zoom);
zoomFactorChanged(factor);
}
bool QV4L2Camera::isFocusModeSupported(QCamera::FocusMode mode) const
{
if (supportedFeatures() & QCamera::Feature::FocusDistance
&& (mode == QCamera::FocusModeManual || mode == QCamera::FocusModeAutoNear
|| mode == QCamera::FocusModeInfinity))
return true;
return mode == QCamera::FocusModeAuto;
}
void QV4L2Camera::setFlashMode(QCamera::FlashMode mode)
{
if (!m_v4l2Info.flashSupported || mode == QCamera::FlashOn)
return;
setV4L2Parameter(V4L2_CID_FLASH_LED_MODE,
mode == QCamera::FlashAuto ? V4L2_FLASH_LED_MODE_FLASH
: V4L2_FLASH_LED_MODE_NONE);
flashModeChanged(mode);
}
bool QV4L2Camera::isFlashModeSupported(QCamera::FlashMode mode) const
{
if (m_v4l2Info.flashSupported && mode == QCamera::FlashAuto)
return true;
return mode == QCamera::FlashOff;
}
bool QV4L2Camera::isFlashReady() const
{
struct v4l2_queryctrl queryControl;
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_AUTO_WHITE_BALANCE;
return m_v4l2FileDescriptor && m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl);
}
void QV4L2Camera::setTorchMode(QCamera::TorchMode mode)
{
if (!m_v4l2Info.torchSupported || mode == QCamera::TorchOn)
return;
setV4L2Parameter(V4L2_CID_FLASH_LED_MODE,
mode == QCamera::TorchOn ? V4L2_FLASH_LED_MODE_TORCH
: V4L2_FLASH_LED_MODE_NONE);
torchModeChanged(mode);
}
bool QV4L2Camera::isTorchModeSupported(QCamera::TorchMode mode) const
{
if (mode == QCamera::TorchOn)
return m_v4l2Info.torchSupported;
return mode == QCamera::TorchOff;
}
void QV4L2Camera::setExposureMode(QCamera::ExposureMode mode)
{
if (m_v4l2Info.autoExposureSupported && m_v4l2Info.manualExposureSupported) {
if (mode != QCamera::ExposureAuto && mode != QCamera::ExposureManual)
return;
int value = QCamera::ExposureAuto ? V4L2_EXPOSURE_AUTO : V4L2_EXPOSURE_MANUAL;
setV4L2Parameter(V4L2_CID_EXPOSURE_AUTO, value);
exposureModeChanged(mode);
return;
}
}
bool QV4L2Camera::isExposureModeSupported(QCamera::ExposureMode mode) const
{
if (mode == QCamera::ExposureAuto)
return true;
if (m_v4l2Info.manualExposureSupported && m_v4l2Info.autoExposureSupported)
return mode == QCamera::ExposureManual;
return false;
}
void QV4L2Camera::setExposureCompensation(float compensation)
{
if ((m_v4l2Info.minExposureAdjustment != 0 || m_v4l2Info.maxExposureAdjustment != 0)) {
int value = qBound(m_v4l2Info.minExposureAdjustment, (int)(compensation * 1000),
m_v4l2Info.maxExposureAdjustment);
setV4L2Parameter(V4L2_CID_AUTO_EXPOSURE_BIAS, value);
exposureCompensationChanged(value / 1000.);
return;
}
}
void QV4L2Camera::setManualIsoSensitivity(int iso)
{
if (!(supportedFeatures() & QCamera::Feature::IsoSensitivity))
return;
setV4L2Parameter(V4L2_CID_ISO_SENSITIVITY_AUTO,
iso <= 0 ? V4L2_ISO_SENSITIVITY_AUTO : V4L2_ISO_SENSITIVITY_MANUAL);
if (iso > 0) {
iso = qBound(minIso(), iso, maxIso());
setV4L2Parameter(V4L2_CID_ISO_SENSITIVITY, iso);
}
}
int QV4L2Camera::isoSensitivity() const
{
if (!(supportedFeatures() & QCamera::Feature::IsoSensitivity))
return -1;
return getV4L2Parameter(V4L2_CID_ISO_SENSITIVITY);
}
void QV4L2Camera::setManualExposureTime(float secs)
{
if (m_v4l2Info.manualExposureSupported && m_v4l2Info.autoExposureSupported) {
int exposure =
qBound(m_v4l2Info.minExposure, qRound(secs * 10000.), m_v4l2Info.maxExposure);
setV4L2Parameter(V4L2_CID_EXPOSURE_ABSOLUTE, exposure);
exposureTimeChanged(exposure / 10000.);
return;
}
}
float QV4L2Camera::exposureTime() const
{
return getV4L2Parameter(V4L2_CID_EXPOSURE_ABSOLUTE) / 10000.;
}
bool QV4L2Camera::isWhiteBalanceModeSupported(QCamera::WhiteBalanceMode mode) const
{
if (m_v4l2Info.autoWhiteBalanceSupported && m_v4l2Info.colorTemperatureSupported)
return true;
return mode == QCamera::WhiteBalanceAuto;
}
void QV4L2Camera::setWhiteBalanceMode(QCamera::WhiteBalanceMode mode)
{
Q_ASSERT(isWhiteBalanceModeSupported(mode));
int temperature = colorTemperatureForWhiteBalance(mode);
int t = setV4L2ColorTemperature(temperature);
if (t == 0)
mode = QCamera::WhiteBalanceAuto;
whiteBalanceModeChanged(mode);
}
void QV4L2Camera::setColorTemperature(int temperature)
{
if (temperature == 0) {
setWhiteBalanceMode(QCamera::WhiteBalanceAuto);
return;
}
Q_ASSERT(isWhiteBalanceModeSupported(QCamera::WhiteBalanceManual));
int t = setV4L2ColorTemperature(temperature);
if (t)
colorTemperatureChanged(t);
}
void QV4L2Camera::readFrame()
{
Q_ASSERT(m_memoryTransfer);
auto dequeued = m_memoryTransfer->dequeueFrame();
if (!dequeued) {
qCWarning(qLcV4L2Camera) << "Cannot take buffer";
if (errno == ENODEV) {
// camera got removed while being active
stopCapturing();
closeV4L2Fd();
}
return;
}
QVideoFrame frame =
QVideoFramePrivate::createFrame(std::move(dequeued->videoBuffer), frameFormat());
if (m_firstFrameTime.tv_sec == -1)
m_firstFrameTime = dequeued->timestamp;
qint64 secs = dequeued->timestamp.tv_sec - m_firstFrameTime.tv_sec;
qint64 usecs = dequeued->timestamp.tv_usec - m_firstFrameTime.tv_usec;
frame.setStartTime(secs * 1000000 + usecs);
frame.setEndTime(frame.startTime() + m_frameDuration);
Q_EMIT newVideoFrame(frame);
}
void QV4L2Camera::setCameraBusy()
{
m_cameraBusy = true;
updateError(QCamera::CameraError, QLatin1String("Camera is in use"));
}
void QV4L2Camera::initV4L2Controls()
{
m_v4l2Info = {};
QCamera::Features features;
const QByteArray deviceName = m_cameraDevice.id();
Q_ASSERT(!deviceName.isEmpty());
closeV4L2Fd();
const int descriptor = qt_safe_open(deviceName.constData(), O_RDWR);
if (descriptor == -1) {
qCWarning(qLcV4L2Camera) << "Unable to open the camera" << deviceName
<< "for read to query the parameter info:"
<< qt_error_string(errno);
updateError(QCamera::CameraError, QLatin1String("Cannot open camera"));
return;
}
m_v4l2FileDescriptor =
std::make_shared<QV4L2FileDescriptor>(QUniqueFileDescriptorHandle{ descriptor });
qCDebug(qLcV4L2Camera) << "FD=" << descriptor;
struct v4l2_queryctrl queryControl;
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_AUTO_WHITE_BALANCE;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
m_v4l2Info.autoWhiteBalanceSupported = true;
setV4L2Parameter(V4L2_CID_AUTO_WHITE_BALANCE, true);
}
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_WHITE_BALANCE_TEMPERATURE;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
m_v4l2Info.minColorTemp = queryControl.minimum;
m_v4l2Info.maxColorTemp = queryControl.maximum;
m_v4l2Info.colorTemperatureSupported = true;
features |= QCamera::Feature::ColorTemperature;
}
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_EXPOSURE_AUTO;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
m_v4l2Info.autoExposureSupported = true;
}
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_EXPOSURE_ABSOLUTE;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
m_v4l2Info.manualExposureSupported = true;
m_v4l2Info.minExposure = queryControl.minimum;
m_v4l2Info.maxExposure = queryControl.maximum;
features |= QCamera::Feature::ManualExposureTime;
}
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_AUTO_EXPOSURE_BIAS;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
m_v4l2Info.minExposureAdjustment = queryControl.minimum;
m_v4l2Info.maxExposureAdjustment = queryControl.maximum;
features |= QCamera::Feature::ExposureCompensation;
}
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_ISO_SENSITIVITY_AUTO;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
queryControl.id = V4L2_CID_ISO_SENSITIVITY;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
features |= QCamera::Feature::IsoSensitivity;
minIsoChanged(queryControl.minimum);
maxIsoChanged(queryControl.minimum);
}
}
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_FOCUS_ABSOLUTE;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
m_v4l2Info.minExposureAdjustment = queryControl.minimum;
m_v4l2Info.maxExposureAdjustment = queryControl.maximum;
features |= QCamera::Feature::FocusDistance;
}
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_AUTO_FOCUS_RANGE;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
m_v4l2Info.rangedFocus = true;
}
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_FLASH_LED_MODE;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
m_v4l2Info.flashSupported = queryControl.minimum <= V4L2_FLASH_LED_MODE_FLASH
&& queryControl.maximum >= V4L2_FLASH_LED_MODE_FLASH;
m_v4l2Info.torchSupported = queryControl.minimum <= V4L2_FLASH_LED_MODE_TORCH
&& queryControl.maximum >= V4L2_FLASH_LED_MODE_TORCH;
}
::memset(&queryControl, 0, sizeof(queryControl));
queryControl.id = V4L2_CID_ZOOM_ABSOLUTE;
if (m_v4l2FileDescriptor->call(VIDIOC_QUERYCTRL, &queryControl)) {
m_v4l2Info.minZoom = queryControl.minimum;
m_v4l2Info.maxZoom = queryControl.maximum;
}
// zoom factors are in arbitrary units, so we simply normalize them to go from 1 to 2
// if they are different
minimumZoomFactorChanged(1);
maximumZoomFactorChanged(m_v4l2Info.minZoom != m_v4l2Info.maxZoom ? 2 : 1);
supportedFeaturesChanged(features);
}
void QV4L2Camera::closeV4L2Fd()
{
Q_ASSERT(!m_memoryTransfer);
m_v4l2Info = {};
m_cameraBusy = false;
m_v4l2FileDescriptor = nullptr;
}
int QV4L2Camera::setV4L2ColorTemperature(int temperature)
{
if (m_v4l2Info.autoWhiteBalanceSupported) {
setV4L2Parameter(V4L2_CID_AUTO_WHITE_BALANCE, temperature == 0 ? true : false);
} else if (temperature == 0) {
temperature = 5600;
}
if (temperature != 0 && m_v4l2Info.colorTemperatureSupported) {
temperature = qBound(m_v4l2Info.minColorTemp, temperature, m_v4l2Info.maxColorTemp);
if (!setV4L2Parameter(
V4L2_CID_WHITE_BALANCE_TEMPERATURE,
qBound(m_v4l2Info.minColorTemp, temperature, m_v4l2Info.maxColorTemp)))
temperature = 0;
} else {
temperature = 0;
}
return temperature;
}
bool QV4L2Camera::setV4L2Parameter(quint32 id, qint32 value)
{
v4l2_control control{ id, value };
if (!m_v4l2FileDescriptor->call(VIDIOC_S_CTRL, &control)) {
qWarning() << "Unable to set the V4L2 Parameter" << Qt::hex << id << "to" << value
<< qt_error_string(errno);
return false;
}
return true;
}
int QV4L2Camera::getV4L2Parameter(quint32 id) const
{
struct v4l2_control control{ id, 0 };
if (!m_v4l2FileDescriptor->call(VIDIOC_G_CTRL, &control)) {
qWarning() << "Unable to get the V4L2 Parameter" << Qt::hex << id << qt_error_string(errno);
return 0;
}
return control.value;
}
void QV4L2Camera::setV4L2CameraFormat()
{
if (m_v4l2Info.formatInitialized || !m_v4l2FileDescriptor)
return;
Q_ASSERT(!m_cameraFormat.isNull());
qCDebug(qLcV4L2Camera) << "XXXXX" << this << m_cameraDevice.id() << m_cameraFormat.pixelFormat()
<< m_cameraFormat.resolution();
v4l2_format fmt = {};
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
auto size = m_cameraFormat.resolution();
fmt.fmt.pix.width = size.width();
fmt.fmt.pix.height = size.height();
fmt.fmt.pix.pixelformat = v4l2FormatForPixelFormat(m_cameraFormat.pixelFormat());
fmt.fmt.pix.field = V4L2_FIELD_ANY;
qCDebug(qLcV4L2Camera) << "setting camera format to" << size << fmt.fmt.pix.pixelformat;
if (!m_v4l2FileDescriptor->call(VIDIOC_S_FMT, &fmt)) {
if (errno == EBUSY) {
setCameraBusy();
return;
}
qWarning() << "Couldn't set video format on v4l2 camera" << qt_error_string(errno);
}
m_v4l2Info.formatInitialized = true;
m_cameraBusy = false;
m_bytesPerLine = fmt.fmt.pix.bytesperline;
m_imageSize = std::max(fmt.fmt.pix.sizeimage, m_bytesPerLine * fmt.fmt.pix.height);
switch (v4l2_colorspace(fmt.fmt.pix.colorspace)) {
default:
case V4L2_COLORSPACE_DCI_P3:
m_colorSpace = QVideoFrameFormat::ColorSpace_Undefined;
break;
case V4L2_COLORSPACE_REC709:
m_colorSpace = QVideoFrameFormat::ColorSpace_BT709;
break;
case V4L2_COLORSPACE_JPEG:
m_colorSpace = QVideoFrameFormat::ColorSpace_AdobeRgb;
break;
case V4L2_COLORSPACE_SRGB:
// ##### is this correct???
m_colorSpace = QVideoFrameFormat::ColorSpace_BT601;
break;
case V4L2_COLORSPACE_BT2020:
m_colorSpace = QVideoFrameFormat::ColorSpace_BT2020;
break;
}
v4l2_streamparm streamParam = {};
streamParam.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
streamParam.parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
auto [num, den] = qRealToFraction(1. / m_cameraFormat.maxFrameRate());
streamParam.parm.capture.timeperframe = { (uint)num, (uint)den };
m_v4l2FileDescriptor->call(VIDIOC_S_PARM, &streamParam);
m_frameDuration = 1000000 * streamParam.parm.capture.timeperframe.numerator
/ streamParam.parm.capture.timeperframe.denominator;
}
void QV4L2Camera::initV4L2MemoryTransfer()
{
if (m_cameraBusy)
return;
Q_ASSERT(!m_memoryTransfer);
m_memoryTransfer = makeUserPtrMemoryTransfer(m_v4l2FileDescriptor, m_imageSize, m_bytesPerLine);
if (m_memoryTransfer)
return;
if (errno == EBUSY) {
setCameraBusy();
return;
}
qCDebug(qLcV4L2Camera) << "Cannot init V4L2_MEMORY_USERPTR; trying V4L2_MEMORY_MMAP";
m_memoryTransfer = makeMMapMemoryTransfer(m_v4l2FileDescriptor, m_bytesPerLine);
if (!m_memoryTransfer) {
qCWarning(qLcV4L2Camera) << "Cannot init v4l2 memory transfer," << qt_error_string(errno);
updateError(QCamera::CameraError, QLatin1String("Cannot init V4L2 memory transfer"));
}
}
void QV4L2Camera::stopCapturing()
{
if (!m_memoryTransfer || !m_v4l2FileDescriptor)
return;
m_notifier = nullptr;
if (!m_v4l2FileDescriptor->stopStream()) {
// TODO: handle the case carefully to avoid possible memory corruption
if (errno != ENODEV)
qWarning() << "failed to stop capture";
}
m_memoryTransfer = nullptr;
m_cameraBusy = false;
}
void QV4L2Camera::startCapturing()
{
if (!m_v4l2FileDescriptor)
return;
setV4L2CameraFormat();
initV4L2MemoryTransfer();
if (m_cameraBusy || !m_memoryTransfer)
return;
if (!m_v4l2FileDescriptor->startStream()) {
qWarning() << "Couldn't start v4l2 camera stream";
return;
}
m_notifier =
std::make_unique<QSocketNotifier>(m_v4l2FileDescriptor->get(), QSocketNotifier::Read);
connect(m_notifier.get(), &QSocketNotifier::activated, this, &QV4L2Camera::readFrame);
m_firstFrameTime = { -1, -1 };
}
QVideoFrameFormat QV4L2Camera::frameFormat() const
{
auto result = QPlatformCamera::frameFormat();
result.setColorSpace(m_colorSpace);
return result;
}
} // namespace QtV4L2
QT_END_NAMESPACE
#include "moc_qv4l2camera_p.cpp"