/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.media.filterfw;
import java.util.LinkedList;
import java.util.Queue;
/**
* A {@link Filter} that pushes out externally injected frames.
* <p> When a frame is injected using {@link #injectFrame(Frame)}, this source will push it on its
* output port and then sleep until another frame is injected.
* <p> Multiple frames may be injected before any frame is pushed out. In this case they will be
* queued and pushed in FIFO order.
*/
class FrameSourceFilter extends Filter {
private final Queue<Frame> mFrames = new LinkedList<Frame>();
FrameSourceFilter(MffContext context, String name) {
super(context, name);
}
@Override
public Signature getSignature() {
return new Signature()
.addOutputPort("output", Signature.PORT_REQUIRED, FrameType.any())
.disallowOtherPorts();
}
private synchronized Frame obtainFrame() {
if (mFrames.isEmpty()) {
enterSleepState();
return null;
} else {
return mFrames.poll();
}
}
/**
* Call this method to inject a frame that will be pushed in a future execution of the filter.
* <p> If multiple frames are injected then they will be pushed one per execution in FIFO order.
*/
public synchronized void injectFrame(Frame frame) {
mFrames.add(frame);
wakeUp();
}
@Override
protected void onProcess() {
Frame frame = obtainFrame();
if (frame != null) {
getConnectedOutputPort("output").pushFrame(frame);
}
}
}