I would like to change what the camera 'captures' to something else during a video call.
Lets say I have an image that I want to be seen on the other side instead of the video sent from the camera.
I want to 'hack' the camera on the iPhone - get control on the data being sent.
Is this feasible?
Not without jailbreaking and a lot of work inside MobilePhone.app
Start by running class-dump-z on /Applications/MobilePhone.app/MobilePhone
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So I have an application that can currently capture video with the front facing iphone camera and then do some processing on the video feed real-time. What I'm trying to do, however, is make this process run in the background and put other controls onscreen. So for example, say I'd like to run the camera and process the image feed, but I want the user to see a black screen with some buttons on it. Any ideas on how to do this?
Just so we get terminology right, by "in the background", you mean running the camera capture while your application is in the foreground, but not displaying the actual video feed. This is possible, but I wanted to make clear that if you move your whole application into the background you will not have access to the camera then.
There are a few ways to do this, but the one that I've spent the most time with is grabbing frames of video (or photos) via AV Foundation. Using an AVCaptureDevice and AVCaptureSession, you can grab the frames of video and route them to an encoder for saving to disk or for processing using your own custom code. None of this requires the camera feed to be displayed onscreen, so you can put up whatever interface you like and do this video recording or photo capture without any onscreen indication.
I would caution that you should make it explicit to your users what you are doing, so that you do not run the risk of violating someone's privacy. Apple does not react kindly to those who do this (for good reason).
I encapsulate a lot of this within my open source GPUImage video and photo processing framework, so you could look at the code for the GPUImageVideoCamera class there to see how I configure the capture inputs. I hand the video frames off to OpenGL ES for the application of filters and other processing operations, but you could ignore that portion of it if you just wanted to do your own encoding or processing.
Heres an exemple code from Apple's doc:
http://developer.apple.com/library/ios/#samplecode/PhotoPicker/Introduction/Intro.html
there is also the way to customize the camera interface.
I am trying to see if it is possible to record a video from the iPhone's camera and write this to a file. I then want the video to start playing on the screen a set time after. This all needs to happen continuously. For example, I want the video on the screen to always be 20 seconds behind what the camera is recording.
Some background:
I have a friend who is a coach and would like for his players to be able to see their last play. This could be accomplished by a feed going to a TV from an iPad always 20 seconds behind what is recorded. This needs to continually run until practice is over. (I would connect the iPad to the TV either with a cable or AirPlay to an Apple TV). The video would never need to be saved and should just be discarded after playing.
Is this even possible with the APIs AVFoundation offers? Will the iPhone let you write to a file and read from a file at the same time to accomplish this? Any other better way to accomplish this?
Thanks for your time.
Instead of writing to a file, how about saving your frames in a circular buffer big enough to hold X seconds of video?
The way I would start to do this would be to look at what's provided in AVCaptureVideoDataOutput and its delegate methods (where you can get the frame data from).
I know how to record a video from the camera on the iPhone, my question, is it possible to take the recording and overlay it on a saved video and save it out as another file?
No, I don't think so. Not using an standard framework. You could probably do something involving screen capture and combing a load of images to make a video. But it would be complicated.
I am working an iphone app that needs to record a vedio automatically.
I used mobile coreservices framework and using that. I made it to came into video mode and clicking on record option its start capturing a vedio. But I want it automatically that is.. I should able to record a video without clicking on record option. That is when video mode comes up its automatically start record video.
Could any one help?
You can look at UIImagePickerControllers startVideoCapture method which is used to start taking video from the camera, this is to be used when you arent using the camera standard controlors and you provide and overlay view. Here is a reference UIImagePickerCOntroller ref. If this is not enough for you, you might want to look into AVFoundation framework which gives you a lot more control over video capturing process...hope that helps
Can anyone confirm how an app like this is done?
PocketCam
Is the way to capture the camera's video stream using AVFoundation?
http://developer.apple.com/iphone/library/documentation/AVFoundation/Reference/AVCaptureVideoDataOutput_Class/Reference/Reference.html#//apple_ref/doc/uid/TP40009544
To be clear, I dont want to capture the video and save it, I want to stream it over a wireless network as an IP camera.
thanks,
I can't confirm how PocketCam works, however, as of iOS4, AVFoundation is the correct way to do this. You will receive a callback with the frame you need. At that point you would push the frame as an image to some server computer listening on the network waiting for frames. Keep in mind that you could be receiving a lot of frames and you may not have enough bandwidth to push all of them depending on the quality/size/resolution of the frames. Here is a technical note from Apple that discusses how to implement frame captures with AVFoundation.