Hey folks. Trying to get started with iPhone video capture stuff, and having a terrible time getting it going.
At the moment, working with an exact copy of the sample code from this Apple Developer Q&A: qa1702; not going to re-paste it here, since it's a relatively big blob of code.
In any case, I copied and pasted that code into an otherwise-empty project, threw in a call to setupCaptureSession into a custom UIView, and figured I should be good to go:
- (void)awakeFromNib {
NSLog(#"init");
[self setupCaptureSession];
}
Unfortunately, when I run the code, my delegate never seems to be called:
- (void)captureOutput:(AVCaptureOutput *)captureOutput
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
fromConnection:(AVCaptureConnection *)connection
{
NSLog(#"New Image!");
}
I'd expect to be seeing a flood of "New Image!" getting dumped to the log, but I'm getting absolutely nothing. I do know that all the initialization code is being run (I threw a few NSLog statements here and there within setupCaptureSession, and they all print).
So, I'd either A) like to figure out what I'm doing wrong or B) see some very simple capture code embedded into a UIView that actually works (the less code, the better). Ideally, the sample code would use the setupCaptureSession code as described in the Apple developer site above.
Note that this code is being tested on an iPhone 3GS running the newest version of iOS 4.
Thanks in advance!
I copied and pasted the same code into a new project and it works fine for me.
Here is what I did:
I created a View Based application in XCode.
I added the following frameworks:CoreMedia, CoreVideo,AVFoundation
I imported AVFoundation into my viewcontroller's header file
I specified my view controller to use the AVCaptureVideoDataOutputSampleBufferDelegate protocol in its interface definition
In the implementation I copied the code from the app document you specified in your question
I commented out this:
[self setSession:session]
I commented out this:
UIImage *image = [self imageFromSampleBuffer:sampleBuffer];
and added this:
NSLog(#"here");
In the viewDidLoad method i put
[self setupCaptureSession];
Build. Run.
The "here" gets printed repeatedly to the console.
Related
I've got a lovely OpenGLES code slice that renders up images for me. When I want to, I can call a function on it:
-(UIImage *)renderToImage;
That does a lot of rendering work and returns me an image. This includes the generation of FBOs, textures, etc.
Lately, I've found myself needing to enhance this. The image generation takes four seconds, so I want to pass off the work to another thread and let the app continue. This seemed simple enough. I made a method with this code:
-(void) generateRandomNewImage:(MyViewController *)evc{
UIImage * renderedImage = [self renderToImage];
NSString * fileLoc = [self writeToTempFile:renderedImage];
NSLog(#"File location:%#",fileLoc);
[evc performSelectorOnMainThread:#selector(imageGenerationComplete:) withObject:fileLoc waitUntilDone:NO];
}
Hopefully you can see the logic going on here. This method renders the image, saves it to the filesystem, and calls a method on the main thread's viewcontroller to let it know the file is ready. This code is inside my opengl renderer. It's called here, in the main thread's viewcontroller:
thread = [[NSThread alloc] initWithTarget:renderer
selector:#selector(generateRandomNewImage:)
object:self];
[thread start];
To me, that seems fine too. When I run this code, I get told in my console that my framebuffer object status were error'ed, with a status of zero. I have no idea why. As a result, I get a blank image (saving to the temp files work, by the way, I've tested them).
To test, I put all of this code into the main thread, didn't create any new threads or anything. It all worked fine. As soon as I try and pass off the image generation to another thread, I hit problems.
Using OpenGL in another thread is not that simple as that, only one thread can use a OpenGL context at a time, and your second thread doesn't have a OpenGL context, thus all OpenGL calls fail.
Solution: Create another OpenGL context for the second thread, and read this.
This is driving me crazy!!!
I'm getting a "Received memory warning. Level=1" whenever I attempt to show a UIImagePickerController with a sourceType = UIImagePickerControllerSourceTypeCamera.
Here is the code from my viewDidLoad where I set things up:
- (void)viewDidLoad {
[super viewDidLoad];
// Set card table green felt background
self.view.backgroundColor = [UIColor colorWithPatternImage: [UIImage imageNamed:#"green_felt_bg.jpg"]];
// Init UIImagePickerController
// Instantiate a UIImagePickerController for use throughout app and set delegate
self.playerImagePicker = [[UIImagePickerController alloc] init];
self.playerImagePicker.delegate = self;
self.playerImagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
}
And here is how I present it modally ..
- (IBAction) addPlayers: (id)sender{
[self presentModalViewController:self.playerImagePicker animated:YES];
}
The result ... UIImagePicker starts to show and then boom ... I get the memory warning ... EVERY TIME! Interestingly enough, if I switch to sourceType = UIImagePickerControllerSourceTypePhotoLibrary ... everything works fine.
What in the heck am I missing or doing wrong? All I want to do is show the camera, take and save a picture.
FYI - I'm testing on my 3GS device.
Thanks to anyone who can help :)
This is very common. As long as you handle the memory warning without crashing and have enough space to keep going, don't let it drive you crazy.
It is not about how much memory your app has used, because it will probably happen even when you write a very simple app which have only one view with one button, clicking the button and then open camera.
I have tested on iPhone 3GS, iPad 2 and iPod touch 3G. It only happened in iPhone 3GS.
I found it will not happen anymore if you restart you device before you execute you app.
Another real solution is to comment the code, [super didReceiveMemoryWarning], in your viewController.
- (void)didReceiveMemoryWarning
{
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
After lots of test on iPhone 3GS with iOS 4.3.2, I found the logic might like that:
-> Open as much as app running on background
-> Presenting a imagePicker of UIImagePickerController, clicking "Back" or "Save" from imagePicker
-> ApplicationDelegate's method, applicationDidReceiveMemoryWarning:(UIApplication *)application, will be invoked
-> Then ViewController's method, didReceiveMemoryWarning:, will be invoked
-> Then viewDidUnload
-> Then viewDidLoad
Then you could find some views have been released and the current view has been pointed to a unexpected one.
By default, [super didReceiveMemoryWarning] will run when ViewController's didReceiveMemoryWarning method is invoked. Commenting it, and viewDidUnload: and viewDidLoad: methods will not be invoked. It means the mem warning has been totally ignored. That's what we expected.
Now after I upgraded to 4.0 it happens to my app too - before in 3.1 there were no warnings.
Actually as you said before, there should be no issue. However, this causes the view that comes after it to load again and viewDidLoad is being called. This messes up my app, since I initialize the view in viewDidLoad - now it gets initialized all over again - even though it shouldn't.
Just as a comment, this might also happen to many other apps that rely on loading the view only once!
It did happen in my app Did I Do That on iOS 4.0 too. It was not consistent, but the most common cause was creating a UIImagePickerController instance and navigating to some large photo stored in one of the albums.
Fixed by persisting state in the didReceiveMemoryWarning method, and loading from state in the viewDidLoad method. One caveat is to remember to clear the state-persisted file in the correct point for your application. For me it was leaving the relevant UIViewController under normal circumstances.
I'm getting the memory warning when opening a UIImagePickerController as well. I'm on 4.01 as well.
But in addition, the UIImagePickerController is running the close shutter animation and stalling there, with the closed shutter on screen.
It seems like the UIImagePickerController's behavior on memory warnings is to close itself.
I could dismiss the UIImagePickerController from the parent ViewController in the didReceiveMemoryWarning method, but that would make for a terrible user experience.
Has anyone seen this problem?
Is there a way to handle the memory warning so that the UIImagePickerController doesn't shut itself down?
I have been struggling with the same problem for some days now. However, resetting my iPhone 4 (clearing out memory) solves the problem so it's not really an app problem.
It appears that a level 1 or 2 memory warning triggers the UIimgPickerController delegate to offload itself. The same happens in my app with the delegate of the delegate (yes it can). After the memory warning however, it will load the delegate (and it's delegate) again causing the viewDidLoad to execute any code that's in there.
I am not sure this happens only while using the UIimgPickerController because testing all that is very time consuming.
I could write some extra code to prevent the code in viewDidLoad en viewWillAppear from execuring while showing the UIimgPickerController but that's not classy, right?
Here's food for thought: it could be
that you are running out of memory
because you are testing your app. With
some memoryleaks it is very well
possible that you are working towards
this problem every time you debug.
The UIImagePickerControllerDelegate is a memory hog because you are capturing high memory assets, be that an image or video. So from the start be sure to specify the medium capture settings, as a start point, reduce this if you don't need the quality:
UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.videoQuality=UIImagePickerControllerQualityTypeMedium;
Then after capturing and using these assets. Remove any temp files from the applications temp folder. Could be an extra obsessive step but its a good habit:
NSFileManager *fileManager = [NSFileManager defaultManager];
if ([fileManager fileExistsAtPath:[lastCapturedFile substringFromIndex:7] ]) {
NSError *error;
// Attempt to delete the folder containing globalDel.videoPath
if ([fileManager removeItemAtPath:[lastCapturedFile substringFromIndex:7] error:&error] != YES) {
NSLog(#"Unable to delete recorded file: %#", [error localizedDescription]);
} else {
NSLog(#"deleted file");
}
}
With above it is clearing the file that was created by the delegate. In some instances if you are transcoding or creating you own assets delete the folder with that file. Note above I am removing the 'file://' part of the url string as the file manager doesn't like it:
[lastCapturedFile substringFromIndex:7]
Other things to consider are covered in the various documentation for what you are doing with that asset - transcoding, image size reduction and more. Beware that any transcoding using the AVFoundation will crash if the UIImagePickerViewController is displaying.
I am trying to apply Mike Chen's answer here, using SDK 3.0. In delegate.m file I implement;
[viewController.view addSubview:[[objc_getClass("PLCameraController") sharedInstance] previewView]];
and in viewcontroller.m I implement:
PLCameraController *cam = [objc_getClass("PLCameraController") sharedInstance];
CapturedImage = [cam _createPreviewImage];
but 'cam' is always nil. Any suggestions?
This won't work when running in the simulator or on an iPod Touch. Are you running this on a physical iPhone with a camera?
Also, if you've dumped the headers correctly, you shouldn't be using the objc_ runtime functions, but rather using the class names. Is the result of objc_getClass("PLCameraController") set to nil?
On a side note: I hope you're not looking to publish your application through the App Store because this sort of private method calling is a great excuse for Apple to reject your application.
To use PLCameraController, you'll need to include the PhotoLibray private framework. The simplest way to do that is drag drop an Image Picker Controller (UIImagePickerController) into your main nib.
I'm getting a EXC_BAD _ACCESS after leaving the method below. At that point htmlDocument becomes invalid, which it should since it falls out of scope. But is that why I'm getting the error? By the time the contentView (UIWebView) loads, htmlDocument is gone. But doesn't contentView already have what it needs from loadHTMLString?
- (void)viewDidLoad {
[super viewDidLoad];
//something other processing here
NSString *htmlDocument = [NSString stringWithFormat:#"<html> \n"
"<body>%#</body> \n"
"</html>", aboutContent];
[contentView loadHTMLString:htmlDocument baseURL:[NSURL URLWithString:#"http://www.abc.com"]];
}
Is there a better way to follow this all the way to failure? Leaving this method is the end of the line for my code. SDK stuff from there.
From your second post, the line you have commented out ([button release]) releases an object already marked to be released automatically.
Either remove the "autorelease" where you are doing an alloc for the button or remove the [button release] statement for the code to compile without errors and exceptions.
If an object is marked for autorelease, calling a release on it will be the same as calling a release on a deallocated instance, hence the error.
At a glance I would say there is nothing wrong with this code, assuming 'aboutContent' is a valid pointer to an object.
You can try running your app with Guard Malloc on the simulator, but that's not guaranteed to turn up anything. I'd suggest you just start commenting out statements until you find the one that's causing the error.
It's not clear what's going on with the code snippet you've just provided without more context. That said, it looks like all you want to do is load some HTML locally in the device. Why not just do this?
- (void)viewDidLoad {
[webView loadRequest:[NSURLRequest
requestWithURL:[NSURL fileURLWithPath:[[NSBundle mainBundle]
pathForResource:#"help/about.html"
ofType:#"html"]isDirectory:NO]]];
}
Using this technique, you can author HTML-based documents right in your phone without the user being wise to the fact that they are actually looking at a web view: this includes Javascript, CSS, the whole ball of a wax. I've seen people actually have their iPhone app go out to the Internet just to render a static page on the Internet which really is not necessary.
From your sample code in the second post, the button you release UIBarButtonItem *button is not retained by anything following the release you have commented out - and so it is deallocated.
You need to add the button to another view (using adSubview) in order for it to display and then you can release it. The parent view will retain the button.
Of course if you are going to refer to the button again, your view controller should keep the retain and release the button in its dealloc.
I'm having a problem with applicationShouldTerminate.
What ever I do it seams that has no effect. Any help would be
appreciated.
I'm well versed in programing but this just gives me headache. Im going
over some basic tutorials for xcode , as I'm new to mac in general, and am currently looking at a simple flashlight app.
It exists but I would like to add a alert box here with option not to
quit.
(void)applicationWillTerminate:(UIApplication *)application
{
[application setIdleTimerDisabled:NO];
}
this has no effect, alert is closed even before its created.
(void)applicationWillTerminate:(UIApplication *)application
{
[application setIdleTimerDisabled:NO];
UIAlertView *alertTest = [[UIAlertView alloc]
initWithTitle:#"This is a Test"
message:#"This is the message contained
with a UIAlertView"
delegate:self
cancelButtonTitle:#"Button #1"
otherButtonTitles:nil];
[alertTest addButtonWithTitle:#"Button #2"];
[alertTest show];
[alertTest autorelease];
NSLog(#"Termination");
}
I did some reading online and found that it should be possible to do
this with
(NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication*)sender
But no mater where I put that declaration I get error: syntax error
before NSApplicationTerminateReply.
There is no syntax error except that xcode seems not to recognize
NSApplicationTerminateReply as valid input.
Any sample code would be greatly appreciated.
I know this is a non-answer, but hopefully I can be helpful:
Displaying a "Really quit?"-type alert like this, even if you can pull it off technically (and I'm not sure you can), is a bad idea and is likely to either cause rejection from the App Store or, at best, an inconsistent user experience because no other apps do this.
The convention with iPhone apps is to save state if necessary, then yield control (for termination) as quickly as possible when the user hits the home button or switches apps.
To ensure a consistent experience, Apple probably has an aggressive timer in place to restrict what you can do in applicationWillTerminate. And even if they don't have a technical measure in place, they probably have an App Store approval policy to ensure that applications quit immediately when they're asked to.
applicationShouldTerminate and NSApplication do not exist on the iPhone. You have to use UIApplication.
The alert view is never shown because the 'show' method does not block, and therefore, the end of 'applicationWillTerminate' is reached immediately after you create the alert view and try to show it. I believe this is by design. You can't really begin asynchronous operations in 'applicationWillTerminate'.
With regards to the applicationShouldTerminate error, in case anyone's curious, NSApplicationTerminateReply and NSApplication seem to be deprecated...even though the OP's method is exactly how it appears in the docs!
Defining your method as the below should build with no errors:
-(BOOL)applicationShouldTerminate :(UIApplication *)application
I think I found the answer to what I wanted to do but will need to check it when I get back home.
Some directions were found here
http://blog.minus-zero.org/
The iPhone 2.0 software was recently released, and with it came the
ability for users to download native apps (i.e., not web sites)
directly to their phones from within the iPhone UI or via iTunes.
Developers (anyone who pays Apple 59GBP for the privilege) can then
write their own apps and have them available for purchase in the App
Store.
One limitation of the Apple-sanctioned SDK is that only one
application is allowed to be running at a time. This presents a
problem for apps such as IM clients, music players and other programs
whose functionality relies on being able to run in the background.
Another example (courtesy of James) would be an app that takes
advantage of the iPhone 3G's GPS chip to create a log of all the
places you visit.
However, there is a neat trick that I discovered: your app will only
get terminated if you switch away from it, and hitting the iPhone's
power button while your app is in the foreground doesn't count as
switching away. The upshot of this is you can create apps which
continue to run while the iPhone is in your pocket - perfect for the
GPS example.
Achieving this is as simple as implementing two methods in your
UIApplication delegate - applicationWillResignActive: and
applicationDidBecomeActive:. Here's a simple example to demonstrate
the effect.
In your UIApplication delegate header file, add a new ivar: BOOL
activeApp. Then, in your implementation, add the following three
methods:
- (void)applicationWillResignActive:(UIApplication *)application {
NSLog(#"resigning active status...");
activeApp = NO;
[self performSelector:#selector(sayHello) withObject:nil afterDelay:1.0];
}
- (void)applicationDidBecomeActive:(UIApplication *)application {
NSLog(#"becoming the active app...");
activeApp = YES;
}
- (void)sayHello {
NSLog(#"Hello!");
if (!activeApp)
[self performSelector:#selector(sayHello) withObject:nil afterDelay:1.0];
}