Play partially downloaded video in swift 3 - swift3

I need to play specific part of a video (eg. form 10 sec to 20 sec).
so I use Alamofire with custom header range to download just this part of the video:
Alamofire.download(videoUrl,
method: .get,
headers: ["Range":String(format: "bytes=%d-%d", startByte, endByte)],
to: destination).response { (response) in
completionHandler(response.destinationURL)
}
so far so good, I can see the downloaded file.
But when I'm trying to play it, avplayer will fail to do that, I'm using
videoAsset.loadValuesAsynchronously(forKeys: [ObserverContexts.urlAssetDurationKey, ObserverContexts.urlAssetPlayableKey])
to load that specific keys async but the duration state can not be loaded:
let durationStatus = self.videoAsset.statusOfValue(forKey: ObserverContexts.urlAssetDurationKey, error: &durationError)
guard durationStatus == .loaded else {
Logger.log.error("durationStatus not loaded: \(self.videoId)")
self.delegate?.onLoadError(error: . durationStatusNotLoaded)
return
}
so this error gets triggered and I can't play the video.
I'm not master in video files, but I think the video file has an header and partially downloading will ruin this header and player can not play it.
so any suggestion or idea (even the simplest) would be appreciated.
tnx in advance.
EDIT: There is definitely something wrong with video header, if I start download 10 second from start of the video, the video get played for 10 sec, BUT the end video time or duration is wrong, how can I fix this?

I don't think IOS or Swift provides this feature of downloading an image from the mid of it and then play it. You can download the video file contents as they are in the form of bits and then can save them with any extension to any file name.
But a video file contains a lots of data in addition to just these bytes that you have downloaded such as header, type, duration, etc. If your downloaded file doesn't contain that data your video will be unplayable.
In this case I think(99% sure) you will have to use native code not just Swift to decode the video from a specific time to your desired time.
A lots of free libraries are available, give them a try. One such kind of library is ffmpeg. Check this as well.
All the best.

This is not the answer to original question, But I managed to achieve my goal by using AVFoundation, now I can download the exact part I want and it is playable :
let downloadUrl = URL(string: videoUrl)!
let asset = AVURLAsset(url: downloadUrl)
let composition = AVMutableComposition()
let videoTrack = composition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID:Int32(kCMPersistentTrackID_Invalid))
let audioTrack = composition.addMutableTrack(withMediaType: AVMediaTypeAudio, preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
let tracks = asset.tracks(withMediaType: AVMediaTypeVideo)
guard let assetVideoTrack = tracks.first else {
Logger.log.debug("video track is not available: \(videoId)")
completionHandler(nil)
return
}
let startCM = CMTime(seconds: startSecond, preferredTimescale: 1)
//let endCM = CMTime(seconds: startSecond + duration, preferredTimescale: 1)
//EDITED
let endCM = CMTime(seconds: duration, preferredTimescale: 1)
let timeRange = CMTimeRangeMake(startCM, endCM)
do {
try videoTrack.insertTimeRange(timeRange, of: assetVideoTrack, at: CMTimeMake(0, 1))
} catch let errorInsertingVideo {
Logger.log.debug("can not get video time range: \(videoId) -- \(errorInsertingVideo.localizedDescription)")
completionHandler(nil)
return
}
videoTrack.preferredTransform = assetVideoTrack.preferredTransform
guard let assetAudioTrack : AVAssetTrack = asset.tracks(withMediaType: AVMediaTypeAudio).first else {
Logger.log.debug("audio track is not available: \(videoId)")
completionHandler(nil)
return
}
do {
try audioTrack.insertTimeRange(timeRange, of: assetAudioTrack, at: CMTimeMake(0, 1))
}catch let errorInsertingAudio {
Logger.log.debug("can not get audio time range: \(videoId) -- \(errorInsertingAudio.localizedDescription)")
completionHandler(nil)
return
}
guard let destinationUrl = self.getDestinationUrl(videoId) else {
// can not access video cache dir
Logger.log.error("can not access video cache dir")
completionHandler(nil)
return
}
let exportSession : AVAssetExportSession = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetPassthrough)!
exportSession.outputURL = destinationUrl
exportSession.timeRange = timeRange
exportSession.outputFileType = AVFileTypeQuickTimeMovie
exportSession.exportAsynchronously(completionHandler: {
switch exportSession.status {
case .completed:
let output = exportSession.outputURL!
completionHandler(output)
case .failed:
completionHandler(nil)
break
default :
completionHandler(nil)
break
}
})
With this trick I can download exactly 10 second (optional) of a video starting from any second at the middle (or start) of the video.
EDIT: ok this code can NOT download middle part, it only works it you start from begining of the Video.
EDIT 2: Fix added.

Related

Loading a file into a C++ object from an iOS App / issues with <iostream> on iOS

I'm working on integrating a C++ library (the GRT, a machine learning toolkit, to be specific) inside of an iOS app.
I've built the GRT as a framework, including using some Objective-C++ wrapper functions to call between my app and the framework.
At the moment, I'm trying to troubleshoot something involving file loading. Specifically, I'm trying to load a file from my app bundle into a GRT module.
Here's where I get the file I want access to, and initialize the GRT wrapper:
func loadTrainingData(){
let documentsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
let fileUrl = documentsUrl.appendingPathComponent("train.grt")
let pipeline = GestureRecognitionPipeline()
let test:Bool = pipeline.load(fileUrl.path)
print(test)
}
And here's the Obj-C++ wrapper code that's called when pipeline.load is called:
- (BOOL)load:(NSString *) path
{
BOOL result = self.instance->load(std::string(path.UTF8String));
if (result) {
std::cout << "GRT config";
std::cout << self.instance->getModelAsString();
std::cout << "GRT info: " << self.instance->getInfo();
}
return result;
}
Finally, here's the actual C++ code that's part of the GRT library, where file loading is handled:
bool GestureRecognitionPipeline::load(const std::string &filename){
std::fstream file;
//Clear any previous setup
clear();
file.open(filename.c_str(), std::iostream::in );
if( !file.is_open() ){
errorLog << __GRT_LOG__ << " Failed to open file with filename: " << filename << std::endl;
return false;
}
...
}
Currently, I'm always failing to have my pipeline object successfully import a file. I don't think it's necessarily something to do with the way I'm accessing the file on the iOS side (though, I could be wrong). Does anyone have any insight? Any appreciated - thanks!
EDIT: I was able to verify that I am loading my file is being loaded properly by this check:
let path = Bundle.main.path(forResource: "acc-orientation", ofType: "grt")
print(path as Any!)
But, I'm still getting the same issues as before.
EDIT 2 I verified that the path is being loaded correctly in the the Obj-C++ wrapper too; which leads me to think it may be something related to the way that is handled in iOS....totally lost here now...
EDIT 3 As suggested by a colleague, I tried using the absoluteString of the file url to pass to my wrapper and the underlying C++ code, since the C++ doesn't have access to the sandboxed environment of iOS. Still the same result:
let documentsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
let fileUrl = documentsUrl.appendingPathComponent("acc-orientation.grt")
let pipeline = GestureRecognitionPipeline()
let test:Bool = pipeline.load(fileUrl.absoluteString)
EDIT 4 As suggested in the comments, I tried using fileSystemRepresentation, but this also didn't bring success.
- (BOOL)load:(NSURL *) url {
BOOL result = self.instance->load(std::string([url fileSystemRepresentation]));
...
}
EDIT 5: I made a simple test project that attempts to only access the file and load it using Swift->Obj-C++->C++ (no framework files, in other words). Here's a link where it can be downloaded. Any help appreciated!
Well, you are almost there. I have downloaded your sample project and got it working. Your problem has to do with the actual location of the file you want to open. At the moment you are trying to open the file from the Documents folder but you never actually copy the file from the App Bundle to the Documents folder. So there are two solutions:
Solution 1: App Bundle
Alter the loadTrainingData method in ViewController.swift to access the file from the App Bundle:
func loadTrainingData(){
let path = Bundle.main.url(forResource: "acc-orientation", withExtension: "grt")
let wrapper = Wrapper()
let test:Bool = wrapper.load(path)
print(test)
}
Solution 2: Documents folder
Copy the file from your App Bundle to your Documents folder right after the first launch. Therefore, copy the following code snippet to your AppDelegate.swift:
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
do {
let url = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("acc-orientation.grt")
let bundleURL = Bundle.main.url(forResource: "acc-orientation", withExtension: "grt")
try FileManager.default.copyItem(at: bundleURL!, to: url)
} catch {
print("File already exists")
}
return true
}
With either of these solutions your FileLoader::load method will return true.
Hope that helps.

FMDB & Swift, " Optional("no such table: Student info") " in real device but it can be done in simulator

I'm newbie, plz help me to solve this out, I still have lots of other things to work on, really thank you thank you very much!
This is a further question after How to use FMDB on the generic iOS device instead of simulator?
When I execute the app on my device and the error threw out: "no such table: Student info", I've print all the path and they all pointed to the same file so I assumed the database has already copied? Console shows like this:
file:///var/mobile/Containers/Data/Application/B5E42F3C-524E-4BBF-8667-1EED0C963A77/Documents/
file:///var/mobile/Containers/Data/Application/B5E42F3C-524E-4BBF-8667-1EED0C963A77/Documents/Data.db
/var/mobile/Containers/Data/Application/B5E42F3C-524E-4BBF-8667-1EED0C963A77/Documents/Data.db
file:///var/mobile/Containers/Data/Application/B5E42F3C-524E-4BBF-8667-1EED0C963A77/Documents/
file:///var/mobile/Containers/Data/Application/B5E42F3C-524E-4BBF-8667-1EED0C963A77/Documents/Data.db
/var/mobile/Containers/Data/Application/B5E42F3C-524E-4BBF-8667-1EED0C963A77/Documents/Data.db
/var/mobile/Containers/Data/Application/B5E42F3C-524E-4BBF-8667-1EED0C963A77/Documents/Data.db
<NSFileManager: 0x17401c1b0>
2017-03-13 16:43:25.446039 Test1.3[16360:5045427] [MC] System group container for systemgroup.com.apple.configurationprofiles path is /private/var/containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles
2017-03-13 16:43:25.457278 Test1.3[16360:5045427] [MC] Reading from public effective user settings.
Insert failed:
Optional("no such table: Student info")
The Data.db is in my bundle resources in target; and the contents in my device is a blank Data.db;
The 2nd question: If you look at the Utility.Swift in the previous question, although the app works good on simulator but after it was loaded, there should be an alertView said "Your database copy successfully", but it didn't. Following is that part of the code:
class func copyFile(_ fileName: NSString){
let dbPath: String = getPath(fileName as String)
let fileManager = FileManager.default
print(dbPath)
print(fileManager)
if !fileManager.fileExists(atPath: dbPath) {
let documentsURL = Bundle.main.resourceURL
let fromPath = documentsURL!.appendingPathComponent(fileName as String)
var error : NSError?
do {
try fileManager.copyItem(atPath: fromPath.path, toPath: dbPath)
}
catch let error1 as NSError {
error = error1
}
if(error != nil){
self.invokeAlertMethod("Error Occured", strBody: "\(error?.localizedDescription)" as NSString, delegate: nil)
}
else{
self.invokeAlertMethod("Successed", strBody: "Your database copy successfully", delegate: nil)
}
}
}
Okay for answering this question I went through your demo.
Where I found couple of mistakes. Let me go through one by one.
1) Your class Utility have a getPath method. What it does it will
keep copying db every time although db is already present in documents
directory and your documents directory db will be replaced with the sample structure. You should always check that if db is already present in documents directory or not.
2) Your db was getting copied into documents directory but structure
wasn't. There was no Student info table in db of documents directory.
3) Please avoid using space or any special characters in table names.
So what I did just corrected your method getPath in utility class.
Please replace your method with this one
class func getPath(_ fileName: String) -> String {
let bundlePath = Bundle.main.path(forResource: "Data", ofType: ".db")
let destPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
let fileManager = FileManager.default
let fullDestPath = URL(fileURLWithPath: destPath).appendingPathComponent("Data.db")
if fileManager.fileExists(atPath: fullDestPath.path){
print("Database file is exist")
print(fileManager.fileExists(atPath: bundlePath!))
}else{
do{
try fileManager.copyItem(atPath: bundlePath!, toPath: fullDestPath.path)
}catch{
print("\n",error)
}
}
print(fullDestPath.path)
return fullDestPath.path
}
After changing this piece of code I tried to run in my device and inserted couple of records.
Let me know if you have any more questions.
If you find this answer helpful just accept it.
First trying delete your app and then reinstall it.
OR
I have created a project over FMDB in Swift which you can use to solve your issue. FMDB Wrapper class you can use in Objective C project as well.
https://github.com/LalitKY/Swift-FMDB
Hope this helps.

sharing a url with whatsapp/Facebook

I'm trying to share a message string from my app in Whatsapp. my code for this is below. my messageString is my message. If messageString does not include a website link this works with no issue. However I now need to include a link in what I'm sharing. Now when I share I just get a blank message in Whatsapp. I have other share functions in the app such as email/sms which display messageString with a url but my Whatsapp one no longer does. How can I fix this?
let urlStringEncoded = messageString.addingPercentEncoding(withAllowedCharacters: .urlUserAllowed)
let url = URL(string: "whatsapp://send?text=\(urlStringEncoded!)")
if UIApplication.shared.canOpenURL(url!) {
if #available(iOS 10.0, *) {
UIApplication.shared.open(url!, options: [:], completionHandler: nil)
} else {
UIApplication.shared.openURL(url!)
}
}
To answer my own question. The problem turned out to be the encoding of the URL with included an Equals Sign. I was unable to send a string containing = with or with out a url.
the problem was fixed by by changing .withAllowedCharacters to
let urlStringEncoded = messageString.addingPercentEncoding(withAllowedCharacters: .alphanumerics)

Web scraping in apple swift 3

I'm a Swift beginner and I'm trying to figure out how to retrieve text from a web article, create a new text file and save the text data into it (Using Swift Playgrounds). Is this possible?
The only thing I could find online regarding the subject was this, and I don't think it is even written for Swift 3:
P.S. If my question needs more details, please let me know instead of putting it on hold. Thanks!
import Cocoa
var url = NSURL(string: "http://finance.yahoo.com/news/tv-news-ces-2017-120931816.html")
if url != nil {
let task = NSURLSession.sharedSession().dataTaskWithURL(url!, completionHandler: { (data, response, error) -> Void in
print(data)
if error == nil {
var urlContent = NSString(data: data, encoding: NSUTF8StringEncoding) as NSString!
print(urlContent)
That's Swift 2.3. In Swift 3 use URL instead of NSURL and use URLSession rather than NSURLSession, etc. You'd also use String rather than NSString. E.g.
let url = URL(string: "http://finance.yahoo.com/news/tv-news-ces-2017-120931816.html")!
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data, error == nil else {
print("\(error)")
return
}
let string = String(data: data, encoding: .utf8)
print("\(string)")
}
task.resume()
If you're going to do this in a playground, remember that this runs asynchronously, so you'll need to set needsIndefiniteExecution.
import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true
To actually parse the HTML, you should consider using a HTML parser like TFHpple (written in Objective-C, but still works great from Swift) or NDHpple (a Swift version, in which I don't have as much confidence as TFHpple, but probably would work fine).
You might want to see How to Parse HTML on iOS. It's dated, but walks you through the concepts (making sure you're not violating ToS of the web site, how to use the parsers, etc.).
If you want to save this to a file, you can do something like:
let fileURL = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
.appendingPathComponent("test.dat")
try! data.write(to: fileURL)
You can use whatever file extension you want.

Ionic 2 / cordova-plugin-file File.writeFile() refuses to create binary file correctly (png image)

In summary
File.writeFile() creates a PNG file of 0 bytes when trying to write a Blob made from base64 data.
In my application, I am trying to create a file that consists of base64 data stored in the db. The rendered equivalent of the data is a small anti-aliased graph curve in black on a transparent background (never more that 300 x 320 pixels) that has previously been created and stored from a canvas element. I have independently verified that the stored base64 data is indeed correct by rendering it at one of various base64 encoders/decoders available online.
Output from "Ionic Info"
--------------------------------
Your system information:
Cordova CLI: 6.3.1
Gulp version: CLI version 3.9.1
Gulp local:
Ionic Framework Version: 2.0.0-rc.2
Ionic CLI Version: 2.1.1
Ionic App Lib Version: 2.1.1
Ionic App Scripts Version: 0.0.39
OS:
Node Version: v6.7.0
--------------------------------
The development platform is Windows 10, and I've been testing directly on a Samsung Galaxy S7 and S4 so far.
I know that the base64 data has to be converted into binary data (as a Blob) first, as File does not yet support writing base64 directly in to an image file. I found various techniques with which to do this, and the code which seems to suit my needs the most (and reflects a similar way I would have done it in java is illustrated below):
Main code from constructor:
this.platform.ready().then(() => {
this.graphDataService.getDataItem(this.job.id).then((data) =>{
console.log("getpic:");
let imgWithMeta = data.split(",")
// base64 data
let imgData = imgWithMeta[1].trim();
// content type
let imgType = imgWithMeta[0].trim().split(";")[0].split(":")[1];
console.log("imgData:",imgData);
console.log("imgMeta:",imgType);
console.log("aftergetpic:");
// this.fs is correctly set to cordova.file.externalDataDirectory
let folderpath = this.fs;
let filename = "dotd_test.png";
File.resolveLocalFilesystemUrl(this.fs).then( (dirEntry) => {
console.log("resolved dir with:", dirEntry);
this.savebase64AsImageFile(dirEntry.nativeURL,filename,imgData,imgType);
});
});
});
Helper to convert base64 to Blob:
// convert base64 to Blob
b64toBlob(b64Data, contentType, sliceSize) {
//console.log("data packet:",b64Data);
//console.log("content type:",contentType);
//console.log("slice size:",sliceSize);
let byteCharacters = atob(b64Data);
let byteArrays = [];
for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
let slice = byteCharacters.slice(offset, offset + sliceSize);
let byteNumbers = new Array(slice.length);
for (let i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
let byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
console.log("size of bytearray before blobbing:", byteArrays.length);
console.log("blob content type:", contentType);
let blob = new Blob(byteArrays, {type: contentType});
// alternative way WITHOUT chunking the base64 data
// let blob = new Blob([atob(b64Data)], {type: contentType});
return blob;
}
save the image with File.writeFile()
// save the image with File.writeFile()
savebase64AsImageFile(folderpath,filename,content,contentType){
// Convert the base64 string in a Blob
let data:Blob = this.b64toBlob(content,contentType,512);
console.log("file location attempt is:",folderpath + filename);
File.writeFile(
folderpath,
filename,
data,
{replace: true}
).then(
_ => console.log("write complete")
).catch(
err => console.log("file create failed:",err);
);
}
I have tried dozens of different decoding techniques, but the effect is the same. However, if I hardcode simple text data into the writeFile() section, like so:
File.writeFile(
folderpath,
"test.txt",
"the quick brown fox jumps over the lazy dog",
{replace: true}
)
A text file IS created correctly in the expected location with the text string above in it.
However, I've noticed that whether the file is the 0 bytes PNG, or the working text file above, in both cases the ".then()" consequence clause of the File Promise never fires.
Additionally, I swapped the above method and used the Ionic 2 native Base64-To-Gallery library to create the images, which worked without a problem. However, having the images in the user's picture gallery or camera roll is not an option for me as I do not wish to risk a user's own pictures while marshalling / packing / transmitting / deleting the data-rendered images. The images should be created and managed as part of the app.
User marcus-robinson seems to have experienced a similar issue outlined here, but it was across all file types, and not just binary types as seems to be the case here. Also, the issue seems to have been closed:
https://github.com/driftyco/ionic/issues/5638
Anybody experiencing something similar, or possibly spot some error I might have caused? I've tried dozens of alternatives but none seem to work.
I had similar behaviour saving media files which worked perfectly on iOS. Nonetheless, I had the issue of 0 bytes file creation on some Android devices in release build (dev build works perfectly). After very long search, I followed the following solution
I moved the polyfills.js script tag to the top of the index.html in the ionic project before the cordova.js tag. This re-ordering somehow the issue is resolved.
So the order should look like:
<script src="build/polyfills.js"></script>
<script type="text/javascript" src="cordova.js"></script>
Works on ionic 3 and ionic 4.
The credits go to 1
I got that working with most of your code:
this.file.writeFile(this.file.cacheDirectory, "currentCached.jpeg", this.b64toBlob(src, "image/jpg", 512) ,{replace: true})
The only difference i had was:
let byteCharacters = atob(b64Data.replace(/^data:image\/(png|jpeg|jpg);base64,/, ''));
instead of your
let byteCharacters = atob(b64Data);
Note: I did not use other trimming etc. like those techniques you used in your constructor class.