void
BMediaEventLooper::Run()
{
CALLED();
if (fControlThread != -1)
return; // thread already running
// until now, the run state is B_UNREGISTERED, but we need to start in B_STOPPED state.
SetRunState(B_STOPPED);
char threadName[32];
sprintf(threadName, "%.20s control", Name());
fControlThread = spawn_thread(_ControlThreadStart, threadName, fCurrentPriority, this);
resume_thread(fControlThread);
// get latency information
fSchedulingLatency = estimate_max_scheduling_latency(fControlThread);
}
/* virtual */ void
BMediaEventLooper::SetRunMode(run_mode mode)
{
CALLED();
// The SetRunMode() hook function is called when someone requests that your node's run mode be changed.
// bump or reduce priority when switching from/to offline run mode
int32 priority;
priority = (mode == B_OFFLINE) ? min_c(B_NORMAL_PRIORITY, fSetPriority) : fSetPriority;
if (priority != fCurrentPriority) {
fCurrentPriority = priority;
if (fControlThread > 0) {
set_thread_priority(fControlThread, fCurrentPriority);
fSchedulingLatency = estimate_max_scheduling_latency(fControlThread);
printf("BMediaEventLooper: SchedulingLatency is %" B_PRId64 "\n",
fSchedulingLatency);
}
}
BMediaNode::SetRunMode(mode);
}
status_t
BMediaEventLooper::SetPriority(int32 priority)
{
CALLED();
// clamp to a valid value
if (priority < 5)
priority = 5;
if (priority > 120)
priority = 120;
fSetPriority = priority;
fCurrentPriority = (RunMode() == B_OFFLINE) ? min_c(B_NORMAL_PRIORITY, fSetPriority) : fSetPriority;
if (fControlThread > 0) {
set_thread_priority(fControlThread, fCurrentPriority);
fSchedulingLatency = estimate_max_scheduling_latency(fControlThread);
printf("BMediaEventLooper: SchedulingLatency is %" B_PRId64 "\n",
fSchedulingLatency);
}
return B_OK;
}
status_t
CodyCam::_SetUpNodes()
{
status_t status = B_OK;
/* find the media roster */
fMediaRoster = BMediaRoster::Roster(&status);
if (status != B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot find the media roster"),
status);
return status;
}
/* find the time source */
status = fMediaRoster->GetTimeSource(&fTimeSourceNode);
if (status != B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot get a time source"), status);
return status;
}
/* find a video producer node */
INFO("CodyCam acquiring VideoInput node\n");
status = fMediaRoster->GetVideoInput(&fProducerNode);
if (status != B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot find a video source. You need "
"a webcam to use CodyCam."), status);
return status;
}
/* create the video consumer node */
fVideoConsumer = new VideoConsumer("CodyCam",
((VideoWindow*)fWindow)->VideoView(),
((VideoWindow*)fWindow)->StatusLine(), NULL, 0);
if (!fVideoConsumer) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot create a video window"),
B_ERROR);
return B_ERROR;
}
/* register the node */
status = fMediaRoster->RegisterNode(fVideoConsumer);
if (status != B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot register the video window"),
status);
return status;
}
fPort = fVideoConsumer->ControlPort();
/* find free producer output */
int32 cnt = 0;
status = fMediaRoster->GetFreeOutputsFor(fProducerNode, &fProducerOut, 1,
&cnt, B_MEDIA_RAW_VIDEO);
if (status != B_OK || cnt < 1) {
status = B_RESOURCE_UNAVAILABLE;
fWindow->ErrorAlert(B_TRANSLATE("Cannot find an available video stream"),
status);
return status;
}
/* find free consumer input */
cnt = 0;
status = fMediaRoster->GetFreeInputsFor(fVideoConsumer->Node(),
&fConsumerIn, 1, &cnt, B_MEDIA_RAW_VIDEO);
if (status != B_OK || cnt < 1) {
status = B_RESOURCE_UNAVAILABLE;
fWindow->ErrorAlert(B_TRANSLATE("Can't find an available connection to "
"the video window"), status);
return status;
}
/* Connect The Nodes!!! */
media_format format;
format.type = B_MEDIA_RAW_VIDEO;
media_raw_video_format vid_format = {0, 1, 0, 239, B_VIDEO_TOP_LEFT_RIGHT,
1, 1, {B_RGB32, VIDEO_SIZE_X, VIDEO_SIZE_Y, VIDEO_SIZE_X * 4, 0, 0}};
format.u.raw_video = vid_format;
/* connect producer to consumer */
status = fMediaRoster->Connect(fProducerOut.source,
fConsumerIn.destination, &format, &fProducerOut, &fConsumerIn);
if (status != B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot connect the video source to "
"the video window"), status);
return status;
}
/* set time sources */
status = fMediaRoster->SetTimeSourceFor(fProducerNode.node,
fTimeSourceNode.node);
if (status != B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot set the time source for the "
"video source"), status);
return status;
}
status = fMediaRoster->SetTimeSourceFor(fVideoConsumer->ID(),
fTimeSourceNode.node);
if (status != B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot set the time source for the "
"video window"), status);
return status;
}
/* figure out what recording delay to use */
bigtime_t latency = 0;
status = fMediaRoster->GetLatencyFor(fProducerNode, &latency);
status = fMediaRoster->SetProducerRunModeDelay(fProducerNode, latency);
/* start the nodes */
bigtime_t initLatency = 0;
status = fMediaRoster->GetInitialLatencyFor(fProducerNode, &initLatency);
if (status < B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Error getting initial latency for the "
"capture node"), status);
return status;
}
initLatency += estimate_max_scheduling_latency();
BTimeSource* timeSource = fMediaRoster->MakeTimeSourceFor(fProducerNode);
bool running = timeSource->IsRunning();
/* workaround for people without sound cards */
/* because the system time source won't be running */
bigtime_t real = BTimeSource::RealTime();
if (!running) {
status = fMediaRoster->StartTimeSource(fTimeSourceNode, real);
if (status != B_OK) {
timeSource->Release();
fWindow->ErrorAlert(B_TRANSLATE("Cannot start time source!"),
status);
return status;
}
status = fMediaRoster->SeekTimeSource(fTimeSourceNode, 0, real);
if (status != B_OK) {
timeSource->Release();
fWindow->ErrorAlert(B_TRANSLATE("Cannot seek time source!"),
status);
return status;
}
}
bigtime_t perf = timeSource->PerformanceTimeFor(real + latency
+ initLatency);
timeSource->Release();
/* start the nodes */
status = fMediaRoster->StartNode(fProducerNode, perf);
if (status != B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot start the video source"),
status);
return status;
}
status = fMediaRoster->StartNode(fVideoConsumer->Node(), perf);
if (status != B_OK) {
fWindow->ErrorAlert(B_TRANSLATE("Cannot start the video window"),
status);
return status;
}
return status;
}
status_t
NodeManager::_StartNodes()
{
status_t status = B_NO_INIT;
if (!fMediaRoster)
return status;
bigtime_t latency = 0;
bigtime_t initLatency = 0;
if (fVideoProducer && fVideoConsumer) {
// figure out what recording delay to use
status = fMediaRoster->GetLatencyFor(fVideoConnection.producer,
&latency);
if (status < B_OK) {
print_error("error getting latency for video producer",
status);
} else
TRACE("video latency: %Ld\n", latency);
status = fMediaRoster->SetProducerRunModeDelay(
fVideoConnection.producer, latency);
if (status < B_OK) {
print_error("error settings run mode delay for video producer",
status);
}
// start the nodes
status = fMediaRoster->GetInitialLatencyFor(
fVideoConnection.producer, &initLatency);
if (status < B_OK) {
print_error("error getting initial latency for video producer",
status);
}
}
initLatency += estimate_max_scheduling_latency();
if (fAudioProducer) {
// TODO: was this supposed to be added to initLatency?!?
bigtime_t audioLatency = 0;
status = fMediaRoster->GetLatencyFor(fAudioConnection.producer,
&audioLatency);
TRACE("audio latency: %Ld\n", audioLatency);
}
BTimeSource* timeSource;
if (fVideoProducer) {
timeSource = fMediaRoster->MakeTimeSourceFor(
fVideoConnection.producer);
} else {
timeSource = fMediaRoster->MakeTimeSourceFor(
fAudioConnection.producer);
}
bool running = timeSource->IsRunning();
// workaround for people without sound cards
// because the system time source won't be running
bigtime_t real = BTimeSource::RealTime();
if (!running) {
status = fMediaRoster->StartTimeSource(fTimeSource, real);
if (status != B_OK) {
timeSource->Release();
print_error("cannot start time source!", status);
return status;
}
status = fMediaRoster->SeekTimeSource(fTimeSource, 0, real);
if (status != B_OK) {
timeSource->Release();
print_error("cannot seek time source!", status);
return status;
}
}
bigtime_t perf = timeSource->PerformanceTimeFor(real + latency
+ initLatency);
timeSource->Release();
// start the nodes
if (fVideoProducer && fVideoConsumer) {
status = fMediaRoster->StartNode(fVideoConnection.consumer, perf);
if (status != B_OK) {
print_error("Can't start the video consumer", status);
return status;
}
status = fMediaRoster->StartNode(fVideoConnection.producer, perf);
if (status != B_OK) {
print_error("Can't start the video producer", status);
return status;
}
}
if (fAudioProducer) {
status = fMediaRoster->StartNode(fAudioConnection.producer, perf);
if (status != B_OK) {
print_error("Can't start the audio producer", status);
return status;
}
}
fPerformanceTimeBase = perf;
return status;
}
/* virtual */ void
BMediaEventLooper::ControlLoop()
{
CALLED();
status_t err = B_OK;
bigtime_t waitUntil = B_INFINITE_TIMEOUT;
bool hasRealtime = false;
bool hasEvent = false;
// While there are no events or it is not time for the earliest event,
// process messages using WaitForMessages. Whenever this funtion times out,
// we need to handle the next event
fSchedulingLatency = estimate_max_scheduling_latency(fControlThread);
while (RunState() != B_QUITTING) {
if (err == B_TIMED_OUT
|| err == B_WOULD_BLOCK) {
// NOTE: The reference for doing the lateness calculus this way can
// be found in the BeBook article "A BMediaEventLooper Example".
// The value which we are going to calculate, is referred there as
// 'lateness'.
media_timed_event event;
if (hasEvent)
err = fEventQueue.RemoveFirstEvent(&event);
else if (hasRealtime)
err = fRealTimeQueue.RemoveFirstEvent(&event);
if (err == B_OK) {
// The general idea of lateness is to allow
// the client code to detect when the buffer
// is handled late or early.
bigtime_t lateness = TimeSource()->RealTime() - waitUntil;
DispatchEvent(&event, lateness, hasRealtime);
}
} else if (err != B_OK)
return;
// BMediaEventLooper compensates your performance time by adding
// the event latency (see SetEventLatency()) and the scheduling
// latency (or, for real-time events, only the scheduling latency).
hasRealtime = fRealTimeQueue.HasEvents();
hasEvent = fEventQueue.HasEvents();
if (hasEvent) {
waitUntil = TimeSource()->RealTimeFor(
fEventQueue.FirstEventTime(),
fEventLatency + fSchedulingLatency);
} else if (!hasRealtime)
waitUntil = B_INFINITE_TIMEOUT;
if (hasRealtime) {
bigtime_t realtimeWait = fRealTimeQueue.FirstEventTime()
- fSchedulingLatency;
if (!hasEvent || realtimeWait <= waitUntil) {
waitUntil = realtimeWait;
hasEvent = false;
} else
hasRealtime = false;
}
if (waitUntil != B_INFINITE_TIMEOUT
&& TimeSource()->RealTime() >= waitUntil) {
err = WaitForMessage(0);
} else
err = WaitForMessage(waitUntil);
}
}
