avfoundation

问题 I have a voice memo component in my app, and I want to allow the user to trim the audio, similar to QuickTime X on Mac OS Ten point Six handles it, or like the Voice Memos app on the iPhone. Here's an example of both: Any help is appreciated. 回答1: I am not a UI programmer by any means. This was a test I wrote to see how to write custom controls. This code may or may not work. I have not touched it in some time. header @interface SUIMaxSlider : UIControl { @private float_t minimumValue; float

问题 I am attempting to implement a barcode scanner. I have an AVCaptureSession that takes in video from AVCaptureDevice. I want to support all orientations. With the following code, when I run the app, everything is fine in the portrait orientation. However in landscape orientation, the view rotates but the video input does not. So I end up with a 90degree rotated video. When I implement -(NSUInteger)supportedInterfaceOrientations method, then everything gets locked to the portrait position. Can

问题 I'm trying to detect dB on a iOS Device, however, I am new to AV audio foundation can't really get to figure it out. I have come across this post: iOS - Detect Blow into Mic and convert the results! (swift), but it is not working for me. My current code is this: import Foundation import UIKit import AVFoundation import CoreAudio class ViewController: UIViewController { var recorder: AVAudioRecorder! var levelTimer = NSTimer() var lowPassResults: Double = 0.0 override func viewDidLoad() {

问题 I'm trying to detect dB on a iOS Device, however, I am new to AV audio foundation can't really get to figure it out. I have come across this post: iOS - Detect Blow into Mic and convert the results! (swift), but it is not working for me. My current code is this: import Foundation import UIKit import AVFoundation import CoreAudio class ViewController: UIViewController { var recorder: AVAudioRecorder! var levelTimer = NSTimer() var lowPassResults: Double = 0.0 override func viewDidLoad() {

问题 I have the following code for generating an audio tone of given frequency and duration. It's loosely based on this answer for doing the same thing on Android (thanks: @Steve Pomeroy): https://stackoverflow.com/a/3731075/973364 import Foundation import CoreAudio import AVFoundation import Darwin class AudioUtil { class func play(frequency: Int, durationMs: Int) -> Void { let sampleRateHz: Double = 8000.0 let numberOfSamples = Int((Double(durationMs) / 1000 * sampleRateHz)) let factor: Double =

问题 I need to obtain the UIImage from uncompressed image data from CMSampleBufferRef. I'm using the code: captureStillImageOutput captureStillImageAsynchronouslyFromConnection:connection completionHandler:^(CMSampleBufferRef imageSampleBuffer, NSError *error) { // that famous function from Apple docs found on a lot of websites // does NOT work for still images UIImage *capturedImage = [self imageFromSampleBuffer:imageSampleBuffer]; } http://developer.apple.com/library/ios/#qa/qa1702/_index.html

问题 I have a bunch of video files that I want to merge into one video file, I am using NSMutableData to achieve the task NSMutableData *concatenatedData = [[NSMutableData alloc] init]; for (int i=0; i <[videoArray count]; i ++) { [concatenatedData appendData: [videoArray objectAtIndex:i]]; } [concatenatedData writeToFile:[[NSString alloc] initWithFormat:@"%@%@", NSTemporaryDirectory(), @"outputConct.mov"] atomically:YES]; UISaveVideoAtPathToSavedPhotosAlbum([[NSString alloc] initWithFormat:@"%@%@

问题 My Requirement: I need to get list of all audio tracks from a video then switch to selected audio track. Approach and Problem: I am using two ways because some time first way do not provide result in that case I am using second one and sometimes both do not get result while VLC media player shows video have audio tracks. I looked apple documentation https://developer.apple.com/library/mac/releasenotes/AudioVideo/RN-AVFoundation/index.html#//apple_ref/doc/uid/TP40010717-CH1-DontLinkElementID_1

问题 Update - I've added a 50 reputation bounty for answering this question! I have an application that needs to put together some videos and photos to create a movie out of them. I am using AVMutableComposition for that. To be able to instruct it how the videos get composed I have to use an AVMutableVideoComposition. This thing has a property called backgroundColor and Apple Documentation says: Only solid BGRA colors are supported; patterns and other supported colors are ignored. If the rendered

问题 I'm trying to splice in images into a pre-existing video to create a new video file using AVFoundation on Mac. So far I've read the Apple documentation example, ASSETWriterInput for making Video from UIImages on Iphone Issues Mix video with static image in CALayer using AVVideoCompositionCoreAnimationTool AVFoundation Tutorial: Adding Overlays and Animations to Videos and a few other SO links Now these have proved to be pretty useful at times, but my problem is that I'm not creating a static