I am trying to use AVCapture in my app to capture the image and post it to a server, but I have a problem with this framework:
With a normal iPhone screen, this framework work very well, but with a retina screen, the AVCamera doesn't work well: The iPhone's video is zooming in to the target higher than the camera, so my camera is too close to the object I want to shoot.
I researched this and saw that the retina device's default camera has this problem too. The image camera and the video camera have different scale zooming, and the AVCamera probably uses the video camera so the target is higher than the image camera. But I want to take the picture with the image camera with AVCapture, how can i do it?
Related
I am developing a video app in which user can merge different videos present in Asset Library. I am able to join the videos but I am facing the orientation issues.
For example, if a video is landscape right and other is landscape left, the second video will be joined upside down. Moreover, I have tried different codes available at stackExchange, however if i apply those codes to portrait videos, they can be transformed to landscape right but leaving black margins on the sides.
Is there any way that when I select a video to be inserted in my project, first its orientation should be checked, if it is other then landscape right, it should be rotated accordingly and in the end if the original video was portrait, the video should be resized as the native player do when we play a video in full screen mode.
Thanks in advance.
I'm building an application which takes photos using the UIImagePickerController. Works great.
The problem however is that I don't want to use image rotation. I always want a photo in portrait mode just as the user sees it on the screen.
When you take your iPhone on the side and then slowly take it back to normal the orientationmode isn't updated. Now when you take the photo the orientation flags in the EXIF data are set.
Is there a way to get rid of orientation support in de imagepicker? Could I just disable the accelerometer?
In my application I want to record a movie using the AVFoundation classes in the landscape (button right) orientation mode.
I set the camera preview layer orientation layer to the landscape orientation and everything looks as it should in the preview.
I record the video using the AVCaptureMovieFileOutput class.
BUT when I play the movie with MVMoviePlayer the video is shown as if I recorded it in portrait mode ! (though the player's interface is displayed in the right landscape orientation as it should)
It seems like the preview layer orientation only affects the view and not what being recorded by the camera.
So how can I record the movie so it will record with the right orientation ?
Thanks
BTW
I use the front camera for the recording
I still have this same problem. Only happens when recording with the front camera on iPhone 4. A recording made with the iPad 2's front camera plays back fine.
I also tried rotating the movie view while playing back, but somehow the transform property of the MPMoviePlayerController.view is ignored, or interpreted strangely (I can only get the playback to flip horizontally, but the image stays 90 degrees rotated...).
Any progress on this?
My goal is to write a custom camera view controller that:
Can take photos in all four interface orientations with both the back and, when available, front camera.
Properly rotates and scales the preview "video" as well as the full resolution photo.
Allows a (simple) effect to be applied to BOTH the preview "video" and full resolution photo.
My previous effort is documented in this question. My latest attempt was to modify Apple's sample GLVideoFrame (from WWDC 2010). However, I have not been able to get the iPhone 4 to display the preview "video" properly when the session preset is AVCaptureSessionPresetPhoto.
Has anyone tried this or know why the example doesn't work with this preset?
Apple's example uses a preset with 640x480 video dimensions and a default texture size of 1280x720. The iPhone 4 back camera delivers only 852x640 when the preset is AVCaptureSessionPresetPhoto.
iOS device camera video/photo dimensions when preset is AVCaptureSessionPresetPhoto:
iPhone 4 back: video is 852x640 & photos are 2592x1936
iPhone 4 front: video & photos are 640x480
iPod Touch 4G back: video & photos are 960x720
iPod Touch 4G front: video & photos are 640x480
iPhone 3GS: video is 512x384 & photos are 2048x1536
Update
I got the same garbled video result when switching Brad Larson's ColorTracking example (blog post) to use the AVCaptureSessionPresetPhoto.
The issue is that AVCaptureSessionPresetPhoto is now context-aware and runs in different resolutions based on whether you are displaying video or still image captures.
The live preview is different for this mode because it pads the rows with extra bytes. I'm guessing this is some sort of hardware optimization.
In any case, you can see how I solved the problem here:
iOS CVImageBuffer distorted from AVCaptureSessionDataOutput with AVCaptureSessionPresetPhoto
The AVCaptureSessionPresetPhoto is for taking pictures, not capturing live feed. You can read about it here: http://developer.apple.com/library/ios/#documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/03_MediaCapture.html
(My belief is that this is actually two different cams or sensors, as they behave very differently, and there's a couple of seconds delay just for switching between the Photo and, say, 640x480).
You can't even use both presets at the same time, and switching between them is a headache as well - How to get both the video output and full photo resolution image in AVFoundation Framework
HTH, although not what you wanted to hear...
Oded.
I'm currently developing an app that has a camera functionality, with a custom camera screen, featuring a preview screen and an overlay.
I'm using the AVFoundation classes and methods as per the eradication of UIScreenCapture.
The problem I have is that the preview data I get from AVCaptureSession is too zoomed in. If i take a picture with that screen, and another with the iPhone's default camera app, without moving the iPhone, the difference in zoom is far too much.
I need the zoom of my app to be the same as is default for iPhone camera app.
I've tried changing the AVCaptureVideoPreviewLayer.videoGravity, to any of it's 3 possible values, to no avail.
Please, any leads on this problem are truly appreciated.
Arcantos' solution was mostly correct. That will work assuming you're on an iPhone 3G (or any device with a camera that supports 640x480). An iPhone 4 may run into some issues there.
A more correct way would be to test for the availability of and apply this preset:
captureSession.sessionPreset = AVCaptureSessionPresetPhoto;
This will use the raw camera data, regardless of the native resolution.
Turned out to be a resolution issue.
It was fixed by using
myCaptureSession.sessionPreset = AVCaptureSessionPreset640x480
Note that iPhone 3g does not support that, so you have to ask wheter the device supports it
[[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo] supportsAvCaptureSessionPreset:AVCaptureSessionPreset640x480]
Is the aspect ratio of your preview pane identical to that of the camera capture data? If not, the OS may be changing the zoom to fit the data rect into your requested aspect ratio.