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• Webcam stream with FFMpeg on iPhone

  6 décembre 2011, par Saphrosit

  I'm trying to send and show a webcam stream from a linux server to an iPhone app. I don't know if it's the best solution, but I downloaded and installed FFMpeg on the linux server (following, for those who want to know, this tutorial).
  FFMpeg is working fine. After a lots of wandering, I managed to send a stream to the client launching

  ffmpeg  -s 320x240 -f video4linux2 -i /dev/video0 -f mpegts -vcodec libx264 udp://192.168.1.34:1234

  where 192.168.1.34 is the address of the client. Actually the client is a Mac, but it is supposed to be an iPhone. I know the stream is sent and received correctly (tested in different ways).
  However I didn't managed to watch the stream directly on the iPhone.
  I thought of different (possible) solutions :

  • first solution : store incoming data in a NSMutableData object. Then, when the stream ends, store it and then play it using a MPMoviePlayerController. Here's the code :

    [video writeToFile:@"videoStream.m4v" atomically:YES];
    
    NSURL *url = [NSURL fileURLWithPath:@"videoStream.m4v"];
    
    
    
    MPMoviePlayerController *videoController = [[MPMoviePlayerController alloc] initWithContentURL:url];
    
    
    
    [videoController.view setFrame:CGRectMake(100, 100, 150, 150)];
    
    
    
    [self.view addSubview:videoController.view];
    
    
    
    [videoController play];

    the problem of this solution is that nothing is played (I only see a black square), even if the video is saved correctly (I can play it directly from my disk using VLC). Besides, it's not such a great idea. It's just to make things work.

  • Second solution : use CMSampleBufferRef to store the incoming video. Much more problems comes with this solution : first of all, there's no CoreMedia.framework in my system. Besides I do not get well what does this class represents and what should I do to make it works : I mean if I start (somehow) filling this "SampleBuffer" with bytes I receive from UDP connection, then it will automatically call the CMSampleBufferMakeDataReadyCallback function I set during creation ? If yes, when ? When the single frame is completed or when the whole stream is received ?

  • Third solution : use AVFoundation framework (neither this is actually available on my Mac). I did not understand if it's actually possible to start recording from a remote source or even from a NSMutableData, a char* or something like that. On AVFoundation Programming Guide I didn't find any reference that say if it's possible or not.

  I don't know which one of this solution is the best for my purpose. ANY suggestion would be appreciate.

  Besides, there's also another problem : I didn't use any segmenter program to send the video. Now, if I'm not getting wrong, segmenter needs to split the source video in smaller/shorter video easier to send. If it is right, then maybe it's not strictly necessary to make things work (may be added later). However, since the server is running under linux, I cannot use Apple's mediastreamsegmeter. May someone suggest an opensource segmenter to use in association with FFMpeg ?

  ---

  UPDATE : I edited my question adding more informations on what I did since now and what my doubts are.

• Streaming jpegs live to iphone app

  14 février 2012, par Raven

  Im progressing through taking the depth camera feed from my kinect and streaming it to my iphone app. I have got to stage of being able save jpegs for every frame created from the kinect depth image (30 fps) and save them to the local disk. I have than been able to convert this to mpeg with ffmpeg.

  My question is now how can I view this live on my iphone ? Basically I want to view it live on the iphone as you are seeing it coming from the kinect.

  Should I use http live streaming and use the segmenter to use apples HttpLiveStreaming functionality ? Or can I stream the raw jpeg image files up in some way as they are saved to disk and than just cycle the images on the phone as they go ?

  Im wondering how video conferencing is achieved on the iphone (facetime/skype etc) ? because I'd prefer that it wasnt played inside the video player, just want to display live content on the screen as it happens.

  Any ideas ? Thanks in advance

• FFMPEG for iPhone recorded video encoding

  16 décembre 2011, par Sarah

  Hi found lots and lots of links for video encoding through ffmpeg 1,2,3,4 etc but they all start with using terminal commands but when i try to implement any on terminal like :

  git clone git ://github.com/lajos/iFrameExtractor.gitit says that-bash : git : command not found.

  Also as per my knowledge it is not possible to use terminal command on iPhone. Can anybody point out how to encode a video recorded through ffmpeg in mp4 format and also to reduce the size of the video ?Thanks in advance.

  EDIT :
  I am already implementing this method to resize my video and it successfully takes place and I am able to send the video on server but then on server side it's giving problem in retrieving the data and to use it.

  - (void)imagePickerController:(UIImagePickerController *)picker 
  
  didFinishPickingMediaWithInfo:(NSDictionary *)info
  
  {
  
      [self convertVideoToLowQuailtyWithInputURL:videoURL1 outputURL:[NSURL fileURLWithPath:videoStoragePath] handler:^(AVAssetExportSession *exportSession)
  
       {
  
           if (exportSession.status == AVAssetExportSessionStatusCompleted)
  
           {
  
               NSLog(@"%@",exportSession.error);
  
               printf("completed\n");
  
           }
  
           else
  
           {
  
               NSLog(@"%@",exportSession.error);
  
               printf("error\n");
  
           }
  
       }];
  
  }
  
  
  
  - (void)convertVideoToLowQuailtyWithInputURL:(NSURL*)inputURL 
  
                                     outputURL:(NSURL*)outputURL 
  
                                       handler:(void (^)(AVAssetExportSession*))handler
  
  {
  
      [[NSFileManager defaultManager] removeItemAtURL:outputURL error:nil];
  
      AVURLAsset *asset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
  
      AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetLowQuality];
  
      exportSession.outputURL = outputURL;
  
      exportSession.outputFileType = AVFileTypeQuickTimeMovie;
  
      [exportSession exportAsynchronouslyWithCompletionHandler:^(void) 
  
       {
  
           handler(exportSession);
  
           [exportSession release];
  
       }];
  
  }