2014/10/15 下午 10:09:22
iphone Programming Glossary: framesUsing FFMPEG library with iPhone SDK for video encoding http://stackoverflow.com/questions/1679649/using-ffmpeg-library-with-iphone-sdk-for-video-encoding
Using the apple FFT and accelerate Framework http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework microphone gets in 1024 floats. Supposing the microphone sampling rate was 44.1kHz so that's ~44 frames sec. So our time window is whatever the time duration of 1024 samples is ie 1 44 s. So we would pack.. There is a cunning trick Extracting precise frequencies from FFT Bins using phase change between frames to get the precise frequency for a given bin. Ok Now onto the code Note the 'ip' in vDSP_fft_zrip '..
How do I export UIImage array as a movie? http://stackoverflow.com/questions/3741323/how-do-i-export-uiimage-array-as-a-movie which in turn has a method called appendSampleBuffer that lets you add individual frames to a video stream. Essentially you 耱l have to 1 Wire the writer NSError error nil AVAssetWriter videoWriter..
Faster alternative to glReadPixels in iPhone OpenGL ES 2.0 http://stackoverflow.com/questions/9550297/faster-alternative-to-glreadpixels-in-iphone-opengl-es-2-0 out that the texture cache support added in iOS 5.0 doesn't just work for fast upload of camera frames to OpenGL ES but it can be used in reverse to get quick access to the raw pixels within an OpenGL ES.. my benchmarks. I found that on my iPhone 4 glReadPixels was the bottleneck in reading 720p video frames for encoding to disk. It limited the encoding from taking place at anything more than 8 9 FPS. Replacing.. Once I have that I configure the FBO that I'll be rendering my video frames to using the following code if GPUImageOpenGLESContext supportsFastTextureUpload CVReturn err CVOpenGLESTextureCacheCreate..
Using FFMPEG library with iPhone SDK for video encoding http://stackoverflow.com/questions/1679649/using-ffmpeg-library-with-iphone-sdk-for-video-encoding
Using the apple FFT and accelerate Framework http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework set it up so that some callback gets triggered every time the microphone gets in 1024 floats. Supposing the microphone sampling rate was 44.1kHz so that's ~44 frames sec. So our time window is whatever the time duration of 1024 samples is ie 1 44 s. So we would pack A with 1024 floats from the mic set log2n 10 2^10 1024 precalculate.. detector as it doesn't have nearly fine enough granularity. There is a cunning trick Extracting precise frequencies from FFT Bins using phase change between frames to get the precise frequency for a given bin. Ok Now onto the code Note the 'ip' in vDSP_fft_zrip ' in place ' ie output overwrites A 'r' means it takes real inputs..
How do I export UIImage array as a movie? http://stackoverflow.com/questions/3741323/how-do-i-export-uiimage-array-as-a-movie AVFoundation framework . The writer has an input of type AVAssetWriterInput which in turn has a method called appendSampleBuffer that lets you add individual frames to a video stream. Essentially you 耱l have to 1 Wire the writer NSError error nil AVAssetWriter videoWriter AVAssetWriter alloc initWithURL NSURL fileURLWithPath..
Faster alternative to glReadPixels in iPhone OpenGL ES 2.0 http://stackoverflow.com/questions/9550297/faster-alternative-to-glreadpixels-in-iphone-opengl-es-2-0 data from OpenGL ES. It isn't readily apparent but it turns out that the texture cache support added in iOS 5.0 doesn't just work for fast upload of camera frames to OpenGL ES but it can be used in reverse to get quick access to the raw pixels within an OpenGL ES texture. You can take advantage of this to grab the pixels.. . This is much much faster than using glReadPixels in my benchmarks. I found that on my iPhone 4 glReadPixels was the bottleneck in reading 720p video frames for encoding to disk. It limited the encoding from taking place at anything more than 8 9 FPS. Replacing this with the fast texture cache reads allows me to encode.. assetWriterVideoInput sourcePixelBufferAttributes sourcePixelBufferAttributesDictionary Once I have that I configure the FBO that I'll be rendering my video frames to using the following code if GPUImageOpenGLESContext supportsFastTextureUpload CVReturn err CVOpenGLESTextureCacheCreate kCFAllocatorDefault NULL __bridge void..
Cocoa: What's the Difference between the frame and the bounds? http://stackoverflow.com/questions/1210047/cocoa-whats-the-difference-between-the-frame-and-the-bounds
Using FFMPEG library with iPhone SDK for video encoding http://stackoverflow.com/questions/1679649/using-ffmpeg-library-with-iphone-sdk-for-video-encoding
Using the apple FFT and accelerate Framework http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework every time the microphone gets in 1024 floats. Supposing the microphone sampling rate was 44.1kHz so that's ~44 frames sec. So our time window is whatever the time duration of 1024 samples is ie 1 44 s. So we would pack A with 1024 floats.. enough granularity. There is a cunning trick Extracting precise frequencies from FFT Bins using phase change between frames to get the precise frequency for a given bin. Ok Now onto the code Note the 'ip' in vDSP_fft_zrip ' in place ' ie output..
streaming video FROM an iPhone http://stackoverflow.com/questions/3444791/streaming-video-from-an-iphone video FROM an iPhone I can get individual frames from the iPhone's cameras just fine. what I need is a way to package them up with sound for streaming to the server. Sending.. 's beginConfiguration and commitConfiguration methods to batch your output change you shouldn't drop any frames between the files. This has many advantages over frame by frame upload The files can be directly used for HTTP live streaming..
How do I export UIImage array as a movie? http://stackoverflow.com/questions/3741323/how-do-i-export-uiimage-array-as-a-movie an input of type AVAssetWriterInput which in turn has a method called appendSampleBuffer that lets you add individual frames to a video stream. Essentially you 耱l have to 1 Wire the writer NSError error nil AVAssetWriter videoWriter AVAssetWriter..
Method for animating images (like a movie) on iPhone without using MPMoviePlayer http://stackoverflow.com/questions/442076/method-for-animating-images-like-a-movie-on-iphone-without-using-mpmovieplayer an NSMutableArray as needed then removed when done to minimize memory use. You can set the transition duration between frames by wrapping the replaceSublayer with method call in a CATransaction like the following CATransaction begin CATransaction..
How to resize the image programatically in objective-c in iphone http://stackoverflow.com/questions/4712329/how-to-resize-the-image-programatically-in-objective-c-in-iphone am displaying large images in a small space. The images are quite large but I am only displaying them in 100x100 pixel frames. My app is responding slowly because of the size fo the images I am using. To improve performance how can I resize the images..
Can use AVCaptureVideoDataOutput and AVCaptureMovieFileOutput at the same time? http://stackoverflow.com/questions/4944083/can-use-avcapturevideodataoutput-and-avcapturemoviefileoutput-at-the-same-time use AVCaptureVideoDataOutput and AVCaptureMovieFileOutput at the same time I want to record video and grab frames at the same time with my code. I am using AVCaptureVideoDataOutput for grab frames and AVCaptureMovieFileOutput for video.. I want to record video and grab frames at the same time with my code. I am using AVCaptureVideoDataOutput for grab frames and AVCaptureMovieFileOutput for video recording. But can't work and get the error code 12780 while working at the same.. this question I can't answer the specific question put but I've been successfully recording video and grabbing frames at the same time using AVCaptureSession and AVCaptureVideoDataOutput to route frames into my own code AVAssetWriter AVAssetWriterInput..
Uploading live streaming video from iPhone [duplicate] http://stackoverflow.com/questions/5062266/uploading-live-streaming-video-from-iphone at .fx .f imageSize.width imageSize.height EDIT UPDATE Several people have asked how to do this without sending the frames to the server one by one. The answer is complex... Basically in the didOutputSampleBuffer function above you add the samples..
How to apply “filters” to AVCaptureVideoPreviewLayer http://stackoverflow.com/questions/5156872/how-to-apply-filters-to-avcapturevideopreviewlayer to Black White. I found a question here that seems to accomplish something similar by capturing the individual video frames in a buffer applying the desired transformations then displaying each frame as an UIImage. For several reasons this seems.. Probably the most performant way of handling this would be to use OpenGL ES for filtering and display of these video frames. You won't be able to do much with an AVCaptureVideoPreviewLayer directly aside from adjusting its opacity when overlaid.. from adjusting its opacity when overlaid with another view or layer. I have a sample application here where I grab frames from the camera and apply OpenGL ES 2.0 shaders to process the video in realtime for display. In this application explained..
Faster alternative to glReadPixels in iPhone OpenGL ES 2.0 http://stackoverflow.com/questions/9550297/faster-alternative-to-glreadpixels-in-iphone-opengl-es-2-0 apparent but it turns out that the texture cache support added in iOS 5.0 doesn't just work for fast upload of camera frames to OpenGL ES but it can be used in reverse to get quick access to the raw pixels within an OpenGL ES texture. You can take.. using glReadPixels in my benchmarks. I found that on my iPhone 4 glReadPixels was the bottleneck in reading 720p video frames for encoding to disk. It limited the encoding from taking place at anything more than 8 9 FPS. Replacing this with the fast.. sourcePixelBufferAttributesDictionary Once I have that I configure the FBO that I'll be rendering my video frames to using the following code if GPUImageOpenGLESContext supportsFastTextureUpload CVReturn err CVOpenGLESTextureCacheCreate..
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