我有一个使用JMF的项目，并在短时间内（几秒到几分钟）记录网络摄像头和音频输入，然后将结果写入文件。
我的项目存在的问题是该文件永远无法正常生成，无法播放。
虽然我发现了很多关于如何通过RTP进行音频和视频多路传输，或者将输入文件从一种格式转换为另一种格式的例子，但我还没有看到一个捕获音频和视频的工作示例，并将其写入文件。
有没有人有一个功能代码的例子呢？
答案 0 :(得分：6)
我找到了为什么我无法从JMF下的两个独立捕获设备生成文件的原因，它与启动命令的排序有关。特别是像处理器这样的东西会采用数据源，或者合并数据源，分配和同步时基并为你启动/停止源代码，所以我试图手动启动数据源的额外工作完全是多余的，并且在工作中投掷扳手。
这是一个痛苦的试验和错误，我建议你阅读每一行代码，理解顺序，并了解所包含的内容，以及在尝试自己实现之前遗漏的内容和原因。如果你不小心的话，JMF就是熊。
哦，记得抓住异常。由于长度限制，我不得不省略该代码。
这是我的最终解决方案：
public void doRecordingDemo() {
// Get the default media capture device for audio and video
DataSource[] sources = new DataSource[2];
sources[0] = Manager.createDataSource(audioDevice.getLocator());
sources[1] = Manager.createDataSource(videoDevice.getLocator());
// Merge the audio and video streams
DataSource source = Manager.createMergingDataSource(sources);
// Create a processor to convert from raw format to a file format
// Notice that we are NOT starting the datasources, but letting the
// processor take care of this for us.
Processor processor = Manager.createProcessor(source);
// Need a configured processor for this next step
processor.configure();
waitForState(processor, Processor.Configured);
// Modify this to suit your needs, but pay attention to what formats can go in what containers
processor.setContentDescriptor(new FileTypeDescriptor(FileTypeDescriptor.QUICKTIME));
// Use the processor to convert the audio and video into reasonable formats and sizes
// There are probably better ways to do this, but you should NOT make any assumptions
// about what formats are supported, and instead use a generic method of checking the
// available formats and sizes. You have been warned!
for (TrackControl control : processor.getTrackControls()) {
if (control.getFormat() instanceof VideoFormat || control.getFormat() instanceof AudioFormat) {
if (control.getFormat() instanceof AudioFormat) {
// In general, this is safe for audio, but do not make assumptions for video.
// Things get a little wonky for video because of how complex the options are.
control.setFormat(new AudioFormat(AudioFormat.GSM));
}
if (control.getFormat() instanceof VideoFormat) {
VideoFormat desiredVideoFormat = null;
Dimension targetDimension = new Dimension(352, 288);
// Search sequentially through this array of formats
VideoFormat[] desiredFormats = new VideoFormat[] {new H263Format(), new JPEGFormat(), new RGBFormat(), new YUVFormat()};
for (VideoFormat checkFormat : desiredFormats) {
// Search the video formats looking for a match.
List<VideoFormat> candidates = new LinkedList<VideoFormat>();
for (Format format : control.getSupportedFormats()) {
if (format.isSameEncoding(checkFormat)) {
candidates.add((VideoFormat) format);
}
}
if (!candidates.isEmpty()) {
// Get the first candidate for now since we have at least a format match
desiredVideoFormat = candidates.get(0);
for (VideoFormat format : candidates) {
if (targetDimension.equals(format.getSize())) {
// Found exactly what we're looking for
desiredVideoFormat = format;
break;
}
}
}
if (desiredVideoFormat != null) {
// If we found a match, stop searching formats
break;
}
}
if (desiredVideoFormat != null) {
// It's entirely possible (but not likely) that we got here without a format
// selected, so this null check is unfortunately necessary.
control.setFormat(desiredVideoFormat);
}
}
control.setEnabled(true);
System.out.println("Enabled track: " + control + " (" + control.getFormat() + ")");
}
}
// To get the output from a processor, we need it to be realized.
processor.realize();
waitForState(processor, Processor.Realized);
// Get the data output so we can output it to a file.
DataSource dataOutput = processor.getDataOutput();
// Create a file to receive the media
File answerFile = new File("recording.mov");
MediaLocator dest = new MediaLocator(answerFile.toURI().toURL());
// Create a data sink to write to the disk
DataSink answerSink = Manager.createDataSink(dataOutput, dest);
// Start the processor spinning
processor.start();
// Open the file
answerSink.open();
// Start writing data
answerSink.start();
// SUCCESS! We are now recording
Thread.sleep(10000); // Wait for 10 seconds so we record 10 seconds of video
try {
// Stop the processor. This will also stop and close the datasources
processor.stop();
processor.close();
try {
// Let the buffer run dry. Event Listeners never seem to get called,
// so this seems to be the most effective way.
Thread.sleep(1000);
} catch (InterruptedException ex) {
Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
}
try {
// Stop recording to the file.
answerSink.stop();
} catch (IOException ex) {
Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
}
} finally {
try {
// Whatever else we do, close the file if we can to avoid leaking.
answerSink.close();
} catch (Exception ex) {
Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
}
try {
// Deallocate the native processor resources.
processor.deallocate();
} catch (Exception ex) {
Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
}
}
}
// My little utility function to wait for a given state.
private void waitForState(Player player, int state) {
// Fast abort
if (player.getState() == state) {
return;
}
long startTime = new Date().getTime();
long timeout = 10 * 1000;
final Object waitListener = new Object();
ControllerListener cl = new ControllerListener() {
@Override
public void controllerUpdate(ControllerEvent ce) {
synchronized (waitListener) {
waitListener.notifyAll();
}
}
};
try {
player.addControllerListener(cl);
// Make sure we wake up every 500ms to check for timeouts and in case we miss a signal
synchronized (waitListener) {
while (player.getState() != state && new Date().getTime() - startTime < timeout) {
try {
waitListener.wait(500);
} catch (InterruptedException ex) {
Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
}
}
}
} finally {
// No matter what else happens, we want to remove this
player.removeControllerListener(cl);
}
}