Implementation Streaming for iOS

Streaming Measurement in iOS

This chapter describes the basic use of the sensor for the measurement of streaming content.

Properties of the Library

Lifecycle of the Measurement

This chapter explains step by step  the use of the sensor and the measurement of streaming content . The following steps are necessary in order to measure a content.

1. Generating the sensor
2. Implementation of the adapter
3. Beginning of the measurement
4. End of the measurement

Generating the Sensor

When you start the app the sensor must be instantiated once. It is not possible to change the site name or the application name after this call.

SpringStreams *spring = [SpringStreams getInstance:@"sitename" a:@"TestApplication"];

From this point on, the method getInstance must be used .

SpringStreams *spring = [SpringStreams getInstance];

Implementation of the Adapter

In principle it is possible to measure any media library with an adapter, that is available within an app to use streaming content .

Therefore the protocol Meta and the interface StreamAdapter must be implemented. The meta object supplies the information regarding the used player, the player version and the screen size.

The library must be able to read continuously the current position on a stream in seconds or  the current position of player. 
 

@protocol Meta <NSObject>
@required
-(NSString*) getPlayerName;
-(NSString*) getPlayerVersion;
-(int) getScreenWidth;
-(int) getScreenHeight;
@end


@interface StreamAdapter : NSObject {
}
- (id) init:(NSObject *)stream;
-(NSObject<Meta>*) getMeta;
-(int) getPosition;
-(int) getDuration;
-(int) getWidth;
-(int) getHeight;
@end

Beginning of the Measurement

This chapter explains step by step how a streaming content is transferred to the library for the measurement.

The following code block shows an example for the use of the library.

...
MPMoviePlayerController *player = [[[MPMoviePlayerController alloc] initWithContentURL: theURL] autorelease];
...

adapter = [[MediaPlayerAdapter alloc] adapter:player];

NSMutableDictionary * atts = [[NSMutableDictionary alloc] init];
[atts setObject:@"iOS/teststream" forKey:@"stream"];
Stream *stream = [spring track:adapter atts:atts];
[atts release];
...

First, the player and the object needs to be instantiated, that is able to deliver the current position on a stream in seconds. In the second step the adapters must be produced, which implements this requirement accurately.

  Then an NSDictionary is generated in order to formulate more detailed information about the stream.   Therefore the attribute stream must always be specified

Next, the method track  is called with the adapter and the description property of the stream. From this point on, the stream is measured by the library as long as the application remains in foreground  and the measured data are cyclically transmitted to the measuring system.

When the application goes into the background , all measurements are stopped and closed, i.e. when the application comes to the foreground again, the method track must be called again.

End of the Measurement

After the measurement of a stream has been started, this stream is measured by the sensor. The measurement can be stopped by calling the method stop on the stream object. All measurements will be automatically stopped by the library, when the application goes into the background.

// start streaming measurement
Stream *stream = [spring track:adapter atts:atts];
...
// stop measurement programmatically
[stream stop];

Foreground- and Background Actions

Ending the application

If the application is closed, the method unload can be called. This call sends the current state of the measurements to the measuring system and then terminates all measurements. This method is automatically called by the library, when the application goes into the background.

...
[[SpringStreams getInstance] unload];

Appendix A

In the following example, the adapter has been implemented for the media player from the standard API.

//
//  MediaPlayerAdapter.m
//  SpringStreams
//
//  Created by Frank Kammann on 26.08.11.
//  Copyright 2011 spring GmbH & Co. KG. All rights reserved.
//

#import <MediaPlayer/MediaPlayer.h>
#import <UIKit/UIKit.h>

#import "SpringStreams.h"


@class MediaPlayerMeta;


@implementation MediaPlayerAdapter

MPMoviePlayerController *controller;
NSObject<Meta> *meta;

- (id)adapter:(MPMoviePlayerController *)player {
    self = [super init:player];

    if (self) {
        meta = [[MediaPlayerMeta alloc] meta:player];
    }
    return self;
}

- (NSObject<Meta>*) getMeta {
    return meta;
}

- (int) getPosition {
    int position = (int)round([controller currentPlaybackTime]);
    // in initialize phase in controller this value is set to -2^31
    if(position < 0) position = 0;
    return position;
}


- (int) getDuration {
    return (int)round([controller duration]);
}

- (int) getWidth {
    return controller.view.bounds.size.width;
}

- (int) getHeight {
    return controller.view.bounds.size.height;
}

- (void)dealloc {
    [meta release];
    [super dealloc];
}


@end



@implementation MediaPlayerMeta

MPMoviePlayerController *controller;

- (id) meta:(MPMoviePlayerController *)player {
    self = [super init];
    if (self) {
        if(player == nil) 
            @throw [NSException exceptionWithName:@"IllegalArgumentException" 
                                           reason:@"player may not be null" 
                                         userInfo:nil];
        controller = player;
    }
    return self;
}

- (NSString*) getPlayerName {
    return @"MediaPlayer";
}

- (NSString*) getPlayerVersion {
    return [UIDevice currentDevice].systemVersion;
}

- (int) getScreenWidth {
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    return screenRect.size.width;
}

- (int) getScreenHeight {
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    return screenRect.size.height;
}

@end

Implementation of the URL Scheme in iOS

Generally for spring measuring purpose, only some modifications need to be applied in your App, if a Panel App is used in your market. 
(This blog may assist your implementation):

Register the URL Scheme accordingly. 

In order to register your URL Scheme into your iOS App, you need to edit the Info.plist file under the "Supporting Files" in your project folder, two ways:

1. you can edit it in any editor, if you do so, please insert the following code:

   	<key>CFBundleURLTypes</key>
   	<array>
   		<dict>
   			<key>CFBundleURLName</key>
   			<string>***</string>      //please change *** to your URL name, not so important
   			<key>CFBundleURLSchemes</key>
   			<array>
   				<string>***</string>  //very important, please replace 
   			</array>
   		</dict>
   	</array>

2. Or you can edit this in xcode, add an item into Info.plist, named "URL types", expand "Item 0" under "URL types", and add two items: "URL identifier", "URL Schemes".

   For "URL identifier", assign your identifier, and for "URL Schemes", add a new item within it named "Item0", REGISTER A UNIQUE URL SCHEME FOR YOUR APP, VERY IMPORTANT!

   It should be like the following: