I want to record a video call made on skype on android phone. But when the call gets connected i start my app which record the video. But it troughs an error (My app cant start recording) "java.lang.RuntimeException: Fail to connect to camera service"
The camera can only be used by one application at a time.
As per the open() documentation:
Creates a new Camera object to access a particular hardware camera. If the same camera is opened by other applications, this will throw a RuntimeException.
http://developer.android.com/guide/topics/media/camera.html states the following:
Accessing cameras
If you have determined that the device on which your application is running has a camera, you must request to access it by getting an instance of Camera (unless you are using an intent to access the camera).
To access the primary camera, use the Camera.open() method and be sure
to catch any exceptions, as shown in the code below:
/** A safe way to get an instance of the Camera object. */
public static Camera getCameraInstance(){
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
}
catch (Exception e){
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
// Camera is not available (in use or does not exist)
So, simply said, your answer is no.
Related
I am using camera to take pictures in the foreground service, which can be used long term like 5 to 10 hours. The problem is when another app starts using camera while the foreground service is running it stop taking pictures and user have to manually restart the service.
I am taking pictures in a loop ( I initializes the camera instance takes a picture then releases the camera and repeat). The solution I see here, is that at the start of each loop iteration I should add a check to see if the camera is currently in use.
How exactly can I check if the camera is in use by any other application or process on device? or is there a better approach to my problem?
If you are using camera2 api, checkout CameraManager.AvailabilityCallback callback.
it will inform you via callback when a cameraID is available/unavailable.
This worked for me!!
if returns true, means camera is free
public boolean isCameraFree() {
Camera camera = null;
try {
camera = Camera.open();
} catch (RuntimeException e) {
return false;
} finally {
if (camera != null) camera.release();
}
return true;
}
I am new to Camera2 framework and trying to understand the logic of creation of capture sessions.
I need a simple thing - preview and record video. I also want to set the correct orientation hint at the time I start recording the video. But I came to a chicken/egg problem.
Here is my logic:
In order to start recording, I am doing this:
val recordRequest = session.device.createCaptureRequest(CameraDevice.TEMPLATE_RECORD).apply {
// Add the preview and recording surface targets
addTarget(viewFinder.holder.surface)
addTarget(recorder.surface)
}.build()
session.setRepeatingRequest(recordRequest, null, cameraHandler)
recorder.setOrientationHint(it) // NOT allowed after getSurface()!
recorder.prepare() // NOT allowed after getSurface()!
recorder.start()
However, I already called recorder.surface (or getSurface()) when I added targets above. One can think that I can prepare and then add targets, however, the documentation for addTarget() says, that the surface The Surface added must be one of the surfaces included in the most recent call to CameraDevice#createCaptureSession
That leads to an interesting problem. Whenever I open the app, I need to create the capture session to start previewing camera image. However, at the point of creation the createCaptureSession() needs to include all the surfaces that will come in future capture requests. Which means that I also need to include the recording surface, even if I simply open camera without recording yet. How do I get this Surface for recording? Well, the documentation says I can get it from MediaRecorder or I can get it from MediaCodec. I want to get it from MediaRecorder since I want to use CamcorderProfiles. However, as I showed in the above code, once I get the surface from the recorder at the point of session creation - I cannot do any changes there at the point of starting recording, like setting orientation hint.
The official Camera2Video sample app does a trick - it uses createPersistentInputSurface however in their example the camera is fixed, which allows them to allocate enough memory for it and use that surface throughout the app lifecycle.
How can this be solved? Am I misunderstanding the concepts here? How can I create the recorder at a later point, when I start recording, but still have the surface for it created earlier, when I open the camera for preview?
Using a persistent input surface is the right approach. Create a new MediaRecorder once you know the orientation for recording, and set its Surface using the persistent input surface.
That's exactly what the Camera2Video sample does, as well:
// React to user touching the capture button
capture_button.setOnTouchListener { view, event ->
when (event.action) {
MotionEvent.ACTION_DOWN -> lifecycleScope.launch(Dispatchers.IO) {
// Prevents screen rotation during the video recording
requireActivity().requestedOrientation =
ActivityInfo.SCREEN_ORIENTATION_LOCKED
// Start recording repeating requests, which will stop the ongoing preview
// repeating requests without having to explicitly call `session.stopRepeating`
session.setRepeatingRequest(recordRequest, null, cameraHandler)
// Finalizes recorder setup and starts recording
recorder.apply {
// Sets output orientation based on current sensor value at start time
relativeOrientation.value?.let { setOrientationHint(it) }
prepare()
start()
}
and recorder is created with an earlier-created persistent surface:
/** Saves the video recording */
private val recorder: MediaRecorder by lazy { createRecorder(recorderSurface)
}
When you say the camera is fixed, do you mean the app orientation being fixed, or that the sample doesn't support switching front/back cameras? None of that should particularly matter for persistent surfaces; you can create a new one when you switch cameras or change orientations, if you need to.
I am having a headache over the Camera API 1 for android. After reading all of the Internet content, I made some sample app that works OK. It creates a service, which then is used to operate with the camera in the background, so there is no preview or activity enabled. To achieve this I use a dummy SurfaceHolder, like this:
protected class MySurfaceHolder implements SurfaceHolder {
private final Surface surface;
private final SurfaceTexture surfaceTexture;
public MySurfaceHolder () {
int[] textures = new int[1];
GLES20.glGenTextures(1, textures, 0);
if (textures.length > 0) {
this.surfaceTexture = new SurfaceTexture(textures[0]);
this.surface = new Surface(this.surfaceTexture);
} else {
this.surface = null;
this.surfaceTexture = null;
}
}
[...]
}
and then I use it like this
// simplified version of my code
try {
initializeCamera(); // open camera and set Camera.Parameters
camera.setPreviewDisplay(new MySurfaceHolder());
camera.startPreview();
camera.unlock();
initializeMediaRecorder(); // create MediaRecorder, set video/audio parameters
mediaRecorder.prepare();
mediaRecorder.start();
// wait until recording finish and exit
} finally {
stopRecording();
}
the Camera and MediaRecorder initialization methods are just like the documentation states they should be (and they work).
Everything works and operates as it should. Almost everything - sometimes, under unknown circumstances the MediaRecorder creates empty files, like 32kB containing only headers and info about the video - no frames. The longer I record like this, the bigger is the file (few kB every few seconds). After 1 minute, the file weights about 80kB. Funny thing is I know that the camera is working and capturing frames (I debugged it a little showing preview frames), but the frames are not written into the output file.
Also when it happens I am not able to record in FHD (1920x1080) - I get the "start failed" message - at this time camera is not capturing frames. The same thing could happen when I use wrong (not supported) video size. I suppose in this case the message is thrown at the mediaRecorder.start(); line, and stopRecording(); is invoked but I am not sure.
After some time or after unknown action the problem is suddenly gone (I don't know when, I don't know how). It happens for sure on Android 5.1, but may happen on other versions as well.
Could this bug be related to my custom surface code?
What could cause the MediaRecorder to not write frames into a file?
Why I am not able to record in FHD, but in the same time I am able to record in HD (1280x720)?
Is there any alternative for MediaRecorder, so I can avoid these bugs?
May it happen when another app is trying to get Camera object, thus distrupting current recording? If so, how to regain access to the Camera object (I apparently am not able to do this now on some devices).
EDIT:
I think I might have a clue. I am calling
camera.setOneShotPreviewCallback(new Camera.PreviewCallback() {
// ... get current frame
}
camera.startPreview();
to get preview frame of current recording. It appears that the bug occurs when I am using this method to get preview frame (at random times). It seems flawed, because not all devices react to this thing properly (sometimes there is no preview frame...). Is there any other, better method of handling current preview frame without the real surface?
I want to open android tablet's camera and get the data from camera in C level. After that I will modify the data, and C level will be efficient.
Now I'm thinking using the V4L2 C code. But I find the open function of V4L2 need the parameter of the camera's name, such as '/dev/video0'. However I can't find something like that in my tablet's dev folder. Besides, I am not sure whether using the V4L2 will be the right solution.
Does anyone know anything about this?
on my device "OpenCV for Android" does not provide required performance neither in 'native' mode nor in 'java' mode. it gives FPS=2 in 1920x1080, in same time when java MediaRecorder can record 1920x1080 with FPS=15
I'm trying to solve it using the code from Android Open Source Project used by native Camera application:
static void android_hardware_Camera_native_setup(JNIEnv *env, jobject thiz,
jobject weak_this, jint cameraId)
{
sp<Camera> camera = Camera::connect(cameraId);
if (camera == NULL) {
jniThrowRuntimeException(env, "Fail to connect to camera service");
return;
}
// make sure camera hardware is alive
if (camera->getStatus() != NO_ERROR) {
jniThrowRuntimeException(env, "Camera initialization failed");
return;
}
jclass clazz = env->GetObjectClass(thiz);
if (clazz == NULL) {
jniThrowRuntimeException(env, "Can't find android/hardware/Camera");
return;
}
// We use a weak reference so the Camera object can be garbage collected.
// The reference is only used as a proxy for callbacks.
sp<JNICameraContext> context = new JNICameraContext(env, weak_this, clazz, camera);
context->incStrong(thiz);
camera->setListener(context);
// save context in opaque field
env->SetIntField(thiz, fields.context, (int)context.get());
}
You can always build a JNI method for the Java classes to get access from C. Another way could be using OpenCV for Android: OpenCV4Android
This gives you a interface to the camera, but as far as I remember, there is currently no support for Android 4.3+.
I can't understand how to display filtered video from camera on Android correctly...
I wrote for sdk-8, so I've used the scheme below:
Camera.setPreviewDisplay(null); // use null surface holder to identify the fact that I don't want to see raw camera preview.
Camera.setPreviewCallbackWithBuffer() + Camera.addCallbackBuffer() // to get camera data, modify it and draw on my GLSurfaceView
And this scheme is wonderful works on 2.2.* androids... and I had been happy, until didn't try application on 4.* =) my callback function for receive frame data doesn't called at all!
According documentation, I shouldn't use null as argument for setPreviewDisplay... without surface instance, video stream will not run... but if I give him surface he will start drawing camera raw preview on that surface....
The question is: How can I correctly draw filtered camera video by my self?!