I'm working on a project and I'd like to know if it's possible to determine whether a video is a boomerang video or not. Boomerang videos generally are about 4 seconds long or slightly shorter.
What I've thought about doing so far is filtering the array I receive from the users camera roll to only display videos which are 4 seconds, but is there a better way?
Any pointers or advice will be greatly appreciated.
This is not an exact answer, but rather one perspective of how to approach this.
From my understanding Boomerang works by taking a super short, super fast burst of photos and stitching them together into a mini video that plays forward and backward and forward and backward. So that means there is chance for the first frame of the video to appear again. So what I suggest is convert each frames of the video into an array of UIImages. Then take the first image of that array and find out if that image is present in the rest of the array.
To make the video into array of images, you can refer Update for Swift 4.2 part of this answer :- https://stackoverflow.com/a/45153948/4637057
From that you will get frames which is an array of UIImages. Now create another array by taking out the first image from that array using frames.remove(at: 0). But before that create image1, which is frames[0]. Then loop through this new array, consider each image as image2 and apply this logic to determine if the first frame is repeating :- https://stackoverflow.com/a/6488838/4637057
The only help i can give you here, is to refer playbackStyle of PHAsset object, if you're using Photos.framework. More information can be found in PhotoKit documentation here
Related
I have two solutions to this problem:
SOLUTION A
Convert the asset to an AVMutableComposition.
For every second keep only one frame , by removing timing for all the other frames using removeTimeRange(...) method.
SOLUTION B
Use the AVAssetReader to extract all individual frames as an array of CMSampleBuffer
Write [CMSampleBuffer] back into a movie skipping every 20 frames or so as per requirement.
Convert the obtained video file to an AVMutableComposition and use scaleTimeRange(..) to reduce overall timeRange of video for timelapse effect.
PROBLEMS
The first solution is not suitable for full HD videos , the video freezes in multiple place and the seekbar shows inaccurate timing .
e.g. A 12 second timelapse might only be shown to have a duration of 5 seconds, so it keeps playing even when the seek has finished.
I mean the timing of the video gets all messed up for some reason.
The second solution is incredibly slow. For a 10 minute HD video the memory would run upto infinity since all execution is done in memory.
I am searching for a technique that can produce a timelapse for a video right away , without waiting time .Solution A kind of does that , but is unsuitable because of timing problems and stuttering.
Any suggestion would be great. Thanks!
You might want to experiment with the inbuilt thumbnail generation functions to see if they are fast/effecient enough for your needs.
They have the benefit of being optimised to generate images efficiently from a video stream.
Simply displaying a 'slide show' like view of the thumbnails one after another may give you the effect you are looking for.
There is iinfomrtaion on the key class, AVAssetImageGenerator, here including how to use it to generate multiple images:
https://developer.apple.com/reference/avfoundation/avassetimagegenerator#//apple_ref/occ/instm/AVAssetImageGenerator/generateCGImagesAsynchronouslyForTimes%3acompletionHandler%3a
I want to implement such a function that enable users to make GIF directly from their camera.
In detail, I want to show users a camera view, and a record button. When the button is tapped, the camera starts to record video. In fact, however, behind the scene the camera is actually taking photos at constant speed, say 1 shot per 0.5 second. When the record ends, we got an array of images and then connect them into a GIF.
I think there might be 2 approaches:
1、Directly taking images: Use AVCaptureStillImageOutput's -captureStillImageAsynchronouslyFromConnection method. But it will block UI every time it is called.
2、Take a video and extract several images from it. I have checked video taking libraries such as PBJVision and SCRecorder, and noticed that taking video is typically writing data to a mp4 file locally. I cannot figure out how to extract images at specific time intervals from a video file. Also, is there a way to store the video in memory?
Could anyone help?
Creating Gif
Create and and export an animated gif via iOS?
Convert Images to gif using ios
Extract Images from Video
Get a particular frame by time value using AVAssetReader
Similar here Creating a Movie from Images
How do I export UIImage array as a movie?
You can use a library called 'Regift' by Matthew Palmer, which will convert video to GIF.
Here it is: https://github.com/matthewpalmer/Regift
You can also check out the following answer here on SO:
https://stackoverflow.com/a/28150109/3288936
Hope this will help! :)
I need to display a sequence procedurally generated images as video sequence preferably with built-in controls (controls would be nice to have, but no requirement) and I'm just looking for a bit of guidance of which API to use. There seem to be a number of options but I'm not sure which one is the best suited to my needs. GPUImage, Core Video, Core Animation, OpenGL ES or something else?
Targetting just iOS 6 and up would be no problem if that helps.
Update: I'd prefer something that would allow me to display the video frames directly rather than writing them to a temporary movie.
Checkout the animationImages property of UIImageView. This may do what you are looking for. Basically you would store all of your images into this array so it can handle the animation for you. UIImageView Reference
I'm working on an iPad app that records and plays videos using AVFoundation classes. I have all of the code for basic record/playback in place and now I would like to add a feature that allows the user to draw and make annotations on the video—something I believe will not be too difficult. The harder part, and something that I have not been able to find any examples of, will be to combine the drawing and annotations into the video file itself. I suspect this is part is accomplished with AVComposition but have no idea exactly how. Your help would be greatly appreciated.
Mark
I do not think that you can actually save a drawing into a video file in iOS. You could however consider using a separate view to save the drawing and synchronize the overlay onto the video using a transparent view. In other words, the user circled something at time 3 mins 42 secs in the video. Then when the video is played back you overlay the saved drawing onto the video at the 3:42 mark. It's not what you want but I think it is as close as you can get right now.
EDIT: Actually there might be a way after all. Take a look at this tutorial. I have not read the whole thing but it seems to incorporate the overlay function you need.
http://www.raywenderlich.com/30200/avfoundation-tutorial-adding-overlays-and-animations-to-videos
I have an AVMutableComposition with a video track and I would like to add a still image into the video track, to be displayed for some given time. The still image is simply a PNG. I can load the image as an asset, but that’s about it, because the resulting asset does not have any tracks and therefore cannot be simply inserted using the insertTimeRange… methods.
Is there a way to add still images to a composition? It looks like the answer is somewhere in Core Animation, but the whole thing seems to be a bit above my head and I would appreciate a code sample or some information pointers.
OK. There’s a great video called Editing Media with AV Foundation from WWDC that explains a lot. You can’t insert images right to the AVComposition timeline, at least I did not find any way to do that. But when exporting or playing an asset you can refer to an AVVideoComposition. That’s maybe not a perfect name for the class, since it allows you to mix between various video tracks in the asset, very much like AVAudioMix does for audio. And the AVVideoComposition has an animationTool property that lets you throw Core Animation layers (CALayer) into the mix. CALayer has a contents property that can be assigned a CGImageRef. Does not help in my case, might help somebody else.
I also need still images in my composition. My line of thinking is a little different. Insert on-the-fly movies of black in place of when images should be appearing (possibly one such video would suffice). Add a dictionary reference to each such insert, linking composition time-ranges to bona-fide desired images. When the correct time range arrives in my full-time custom compositor, pull out the desired image and paint that into the output pixel buffer, ignoring the incoming black frames from the composition. I think that'd be another way of doing it.