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/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
This library is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
**********/
// "liveMedia"
// Copyright (c) 1996-2005 Live Networks, Inc. All rights reserved.
// A template for a MediaSource encapsulating an audio/video input device
// Implementation
#include "DeviceSource.hh"
DeviceSource*
DeviceSource::createNew(UsageEnvironment& env,
DeviceParameters params) {
return new DeviceSource(env, params);
}
DeviceSource::DeviceSource(UsageEnvironment& env,
DeviceParameters params)
: FramedSource(env), fParams(params) {
// Any initialization of the device would be done here
}
DeviceSource::~DeviceSource() {
}
void DeviceSource::doGetNextFrame() {
// Arrange here for our "deliverFrame" member function to be called
// when the next frame of data becomes available from the device.
// This must be done in a non-blocking fashion - i.e., so that we
// return immediately from this function even if no data is
// currently available.
//
// If the device can be implemented as a readable socket, then one easy
// way to do this is using a call to
// envir().taskScheduler().turnOnBackgroundReadHandling( ... )
// (See examples of this call in the "liveMedia" directory.)
// If, for some reason, the source device stops being readable
// (e.g., it gets closed), then you do the following:
if (0 /* the source stops being readable */) {
handleClosure(this);
return;
}
}
void DeviceSource::deliverFrame() {
// This would be called when new frame data is available from the device.
// This function should deliver the next frame of data from the device,
// using the following parameters (class members):
// 'in' parameters (these should *not* be modified by this function):
// fTo: The frame data is copied to this address.
// (Note that the variable "fTo" is *not* modified. Instead,
// the frame data is copied to the address pointed to by "fTo".)
// fMaxSize: This is the maximum number of bytes that can be copied
// (If the actual frame is larger than this, then it should
// be truncated, and "fNumTruncatedBytes" set accordingly.)
// 'out' parameters (these are modified by this function):
// fFrameSize: Should be set to the delivered frame size (<= fMaxSize).
// fNumTruncatedBytes: Should be set iff the delivered frame would have been
// bigger than "fMaxSize", in which case it's set to the number of bytes
// that have been omitted.
// fPresentationTime: Should be set to the frame's presentation time
// (seconds, microseconds).
// fDurationInMicroseconds: Should be set to the frame's duration, if known.
if (!isCurrentlyAwaitingData()) return; // we're not ready for the data yet
// Deliver the data here:
// After delivering the data, switch to another task, and inform
// the reader that he has data:
nextTask()
= envir().taskScheduler().scheduleDelayedTask(0, (TaskFunc*)afterGetting,
this);
}
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