iPhone development mpmovieplayer crashing

问题:

I am working on an app that will let me play different videos on the iPad remotely with an iPhone. I have been following along with apples example for a video player but I've been having some troubles. The videos play just fine and I can get it to play from a variety of videos but switching between them a few times it will crash and i get this in the debugger:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'An        AVPlayerItem cannot be associated with more than one instance of AVPlayer'
*** First throw call stack:
(0x380da8bf 0x37c261e5 0x30acbcb5 0x30abc1f7 0x30ac3bf3 0x30c93d55 0x30c95f7b 0x380ad2dd   0x380304dd 0x380303a5 0x37e07fcd 0x31bb0743 0x25e5 0x257c)

This is the code I am using to create the player:

MPMoviePlayerController *player = [[MPMoviePlayerController alloc] initWithContentOfURL:movieURL];
if (player) {
    [self setMoviePlayerController:player];
    [self installMovieNotificationObservers];
    [player setContentURL:movieURL];
    [player setMovieSourceType:sourceType];
    [self applyUserSettingsToMoviePlayer];
    [self.view addSubview:self.backgroundView];
    [player.view setFrame:self.view.bounds];
    [player.view setBackgroundColor = [UIColor blackColor];
    [self.view addSubview:player.view];
}

And when the current movie is stopped I use:

[[self moviePlayerController] stop];

MPMoviePlayerController *player = [self moviePlayerController];
[player.view removeFromSuperview];

[self removeMovieNotificationHandlers];
[self setMoviePlayerController:nil];

Edit: So Ive now discovered it happens every time i try and switch a video for the 11th time. weird! I'm practically pulling my hair out.

回答1:

What fixed this problem for me was stopping the MPMoviePlayerController before doing the setContentURL.

    MPMoviePlayerController *streamPlayer;

    [streamPlayer stop];
    [streamPlayer setContentURL:[NSURL URLWithString:selectedStation]];

回答2:

In the implementation you have above, ARC doesn't know that the MPMoviePlayerController is finished and needs to be released.

Define MPMoviePlayerController in your .h file and make it accessible via a @property (and @synthesize).

@property (strong, nonatomic) MPMoviePlayerController * moviePlayerController;

Then take the result of your alloc & init and assign it to that. I.E.

self.moviePlayerController = [[MPMoviePlayerController alloc] initWithContentOfURL:movieURL];

回答3:

you should just keep the moviePlayerController and if you want to play another video, just use

[self.moviePlayerController setContentURL:movieURL];

then in your notification callback:

- (void) moviePlayBackDidFinish:(NSNotification*)notification
{
    self.moviePlayer = nil;
    [self initanothermovieplayerandplay];
}

and please do not remove the notification handler from notification center, only do this in dealloc method of your VC.

now let's add some fade when the movie play is done:

- (void) moviePlayBackDidFinish:(NSNotification*)notification
{
    [UIView animateWithDuration:1
                      delay: 0.0
                    options: UIViewAnimationOptionCurveEaseIn
                 animations:^{
                     // one second to fade out the view
                     self.moviePlayer.view.alpha = 0.0;
                 }
                 completion:^(BOOL finished){
                       self.moviePlayer = nil;
                       [self initanothermovieplayerandplay];
                 }
}

回答4:

I had exactly the same problem. Nothing was wrong with my and i guess with your code :) Just a broken video file was mine problem. Changing *.mov type to m4a for example fixed it. Maybe one or more of the files you play are corrupted? Try to find out which files lead to crash and than if u can try to quickly forward backward the play position of one of them while playing - this should lead to crash in few tries. This is how i found the bad files. By the way all my bad files were movies .mov made with Snapz Pro X :)

回答5:

Not sure if it is the case here, but we had a lot of problems, because the MPMoviePlayer is a singleton somewhere under the hood. What we did is, that we implemented our own MoviePlayer wrapper which can be used from UIView (actually we have exactly one subclass of UIView MoviePlayerView to show movies) and assures that only one instance of MPMoviePlayerController exists. The code goes like this (it contains some special stuff, we need to show previews/thumbs the way we want etc. you should clean up as well as some release-statements):

//  MoviePlayer.h

#import <Foundation/Foundation.h>
#import <MediaPlayer/MediaPlayer.h>
#import "Logger.h"

@class MoviePlayerView;

@interface MoviePlayer : NSObject
{
  @private
  MPMoviePlayerController *controller;
  MoviePlayerView *currentView;
}

@property (nonatomic, readonly) MPMoviePlayerController *controller;

+(MoviePlayer *) instance;

-(void) playMovie:(NSURL*)movieURL onView:(MoviePlayerView *)view;
-(void) stopMovie;

@end



//  MoviePlayer.m




#import "MoviePlayer.h"
#import "MoviePlayerView.h"

@implementation MoviePlayer

@synthesize controller;

static MoviePlayer *player = nil;

#pragma mark Singleton management

+(MoviePlayer *) instance
{
  @synchronized([MoviePlayer class])
  {
    if (player == nil) 
    {
      player = [[super allocWithZone:NULL] init];
      player->controller = [[MPMoviePlayerController alloc] init];
      player->controller.shouldAutoplay = NO;
      player->controller.scalingMode = MPMovieScalingModeAspectFit;
      player->currentView = nil;
    }
    return player;
  }
}

+(id) allocWithZone:(NSZone *)zone
{
  return [[self instance] retain];
}

-(id) copyWithZone:(NSZone *)zone
{
  return self;
}

-(id) retain
{
  return self;
}

-(NSUInteger) retainCount
{
  return NSUIntegerMax; 
}

-(oneway void) release
{
  // singleton will never be released
}

-(id) autorelease
{
  return self;
}

#pragma mark MoviePlayer implementations

-(void) stopMovie
{
  @synchronized(self)
  {
    if (controller.view.superview)
    {
      [controller.view removeFromSuperview];
    }
    if (controller.playbackState != MPMoviePlaybackStateStopped)
    {
      [controller pause];
      [controller stop];
    }
    if (currentView)
    {
      NSNotificationCenter *ntfc = [NSNotificationCenter defaultCenter];
      [ntfc removeObserver:currentView name:MPMoviePlayerLoadStateDidChangeNotification object:controller];
      [ntfc removeObserver:currentView name:MPMoviePlayerPlaybackStateDidChangeNotification object:controller];
      currentView = nil;
    }
  }
}

-(void) playMovie:(NSURL*)movieURL onView:(MoviePlayerView *)view
{
  @synchronized(self)
  {
    [self stopMovie];
    currentView = view;

    NSNotificationCenter *ntfc = [NSNotificationCenter defaultCenter];
    [ntfc addObserver:currentView 
             selector:@selector(loadStateDidChange:)
                 name:MPMoviePlayerLoadStateDidChangeNotification 
               object:controller];
    [ntfc addObserver:currentView 
             selector:@selector(playbackStateDidChange:)
                 name:MPMoviePlayerPlaybackStateDidChangeNotification
               object:controller];

    [controller setContentURL:movieURL];
    controller.view.frame = view.bounds;
    [view addSubview: controller.view];
    [controller play];
  }
}

@end


//  MoviePlayerView.h

#import <UIKit/UIKit.h>
#import "MoviePlayer.h"


@interface MoviePlayerView : MediaView 
{
  NSURL *movieURL;
  NSURL *thumbnailURL;
  UIImageView *previewImage;
  UIView *iconView;
  BOOL hasPreviewImage;
}

-(id) initWithFrame:(CGRect)frame thumbnailURL:(NSURL *)thumbnail movieURL:(NSURL *)movie;
-(void) loadStateDidChange:(NSNotification *)ntf;
-(void) playbackStateDidChange:(NSNotification *)ntf;

@end



//  MoviePlayerView.m

#import "MoviePlayerView.h"

@interface MoviePlayerView()
-(void) initView;
-(void) initController;
-(void) playMovie;
-(void) setActivityIcon;
-(void) setMovieIcon:(float)alpha;
-(void) clearIcon;
-(CGPoint) centerPoint;
@end

@implementation MoviePlayerView

-(id) initWithFrame:(CGRect)frame thumbnailURL:(NSURL *)thumbnail movieURL:(NSURL *)movie
{
  self = [super initWithFrame:frame];
  if (self) 
  {
    movieURL = [movie retain];
    thumbnailURL = [thumbnail retain];
    [self initView];
    [self initController];
    hasPreviewImage = NO;
    loadingFinished = YES;
  }
  return self;
}

-(void) dealloc
{
  [iconView release];
  [previewImage release];
  [movieURL release];
  [super dealloc];
}

-(void)initView
{
  self.backgroundColor = [UIColor blackColor];

  // add preview image view and icon view
  previewImage = [[UIImageView alloc] initWithFrame:self.bounds];
  [previewImage setContentMode:UIViewContentModeScaleAspectFit];
  UIImage *img = nil;
  if (thumbnailURL)
  {
    img = [ImageUtils loadImageFromURL:thumbnailURL];
    if (img)
    {
      previewImage.image = img;
      hasPreviewImage = YES;
    }
  }
  [self addSubview:previewImage];
  [self setMovieIcon:(hasPreviewImage ? 0.8f : 0.3f)];
}

-(void)initController
{
  UITapGestureRecognizer *rec = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(playMovie)];
  [self addGestureRecognizer:rec];
  [rec release];
}

-(void)playMovie
{
  [[MoviePlayer instance] playMovie:movieURL onView:self];
  [self setActivityIcon];
}

-(void) loadStateDidChange:(NSNotification *)ntf
{
  MPMoviePlayerController *controller = [ntf object];
  switch (controller.loadState)
  {
    case MPMovieLoadStatePlayable:
    {
      [self clearIcon];
      [controller setFullscreen:YES animated:YES];
      break;
    }
    case MPMovieLoadStateStalled:
    {
      [self setActivityIcon];
      break;
    }
    default:
    {
      break; // nothing to be done
    }
  }
}

-(void) playbackStateDidChange:(NSNotification *)ntf
{
  MPMoviePlayerController *controller = [ntf object];
  switch (controller.playbackState) 
  {
    case MPMoviePlaybackStatePlaying:
    {
      [self clearIcon];
      break;
    }
    case MPMoviePlaybackStateStopped:
    {
      [self setMovieIcon:(hasPreviewImage ? 0.8f : 0.3f)];
      break;
    }
    case MPMoviePlaybackStatePaused:
    {
      [self setMovieIcon:0.8f];
      break;
    }
    case MPMoviePlaybackStateInterrupted:
    {
      [self setActivityIcon];
      break;
    }
    default:
    {
      break; // nothing to be done
    }
  }
}

-(void) setActivityIcon
{
  [self clearIcon];
  iconView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
  iconView.center = [self centerPoint];
  [self addSubview:iconView];
  [iconView performSelector:@selector(startAnimating)];
}

-(void) setMovieIcon:(float)alpha
{
  [self clearIcon];
  iconView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"icon_movie.png"]];
  iconView.center = [self centerPoint];
  iconView.alpha = alpha;
  [self addSubview:iconView];
}

-(void) clearIcon
{
  if (iconView)
  {
    SEL stop = @selector(stopAnimating);
    if ([iconView respondsToSelector:stop])
    {
      [iconView performSelector:stop];
    }
    [iconView removeFromSuperview];
    [iconView release];
    iconView = nil;
  }
}

-(CGPoint) centerPoint
{
  return CGPointMake(roundf(self.bounds.size.width / 2.0f), roundf(self.bounds.size.height / 2.0f));
}

-(void)resize
{
  for (UIView *view in [self subviews]) 
  {
    if (view == iconView)
    {
      iconView.center = [self centerPoint];
      continue;
    }
    view.frame = self.bounds;
  }
  [self addCaptionLabel];
}

-(void) layoutSubviews
{
  [super layoutSubviews];
  [self resize];
}

@end

回答6:

...
player = [[MPMoviePlayerController alloc] initWithContentURL: [NSURL URLWithString:...
...

but I didn't gave internet connection to phone (wi-fi) :)

回答7:

I had the same problem. My solution is using prepareToPlay:

MPMoviePlayerController *player = [[MPMoviePlayerController alloc] initWithContentOfURL:movieURL];

if (player) {
   [player prepareToPlay];
   //...
}

回答8:

This error seems to be thrown for lots of different reasons, but the reason I found was that the MPMoviePlayerController class freaks out if you call methods in a certain order. From an IRC Channel:

"apparently if you call prepareToPlay WHILE setting source type and NOT setting the view yet causes this crash"

So I fixed this by just making sure that I called prepareToPlay: LAST (or second to last, with the last being play:).

It is also weird because my original code worked in iOS 5.1, but this problem suddenly manifested when I started using the iOS 6.0 sdk. It is possibly a bug in the MPMoviePlayerController code, so I'm going to be filing a radar report on it, as calling prepareToPlay: before setting the view / setting the sourceFileType should not throw an exception (or at least an exception that seemingly has nothing to do with the actual error)