I want to return CMsampleBuffer from following Method -(CMSampleBufferRef )readMovieFrames{ AVURLAsset *mAsset = [[AVURLAsset

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Asked: June 16, 20262026-06-16T04:28:18+00:00 2026-06-16T04:28:18+00:00

I want to return CMsampleBuffer from following Method -(CMSampleBufferRef )readMovieFrames{ AVURLAsset *mAsset = [[AVURLAsset

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I want to return CMsampleBuffer from following Method

-(CMSampleBufferRef )readMovieFrames{

    AVURLAsset *mAsset = [[AVURLAsset alloc] initWithURL:sampleURL options:NULL];
    tracks = [mAsset tracksWithMediaType:AVMediaTypeVideo];

//here getting one index

    AVAssetTrack *mTrack = [tracks objectAtIndex:0];


    NSString* key = (NSString*)kCVPixelBufferPixelFormatTypeKey;
    NSNumber* value = [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA];
    NSDictionary * settings = [[NSDictionary alloc] initWithObjectsAndKeys:value, key, nil];

    AVAssetReaderTrackOutput *mOutput = [[AVAssetReaderTrackOutput alloc]
                                         initWithTrack:mTrack outputSettings:settings];


    AVAssetReader *mReader = [[AVAssetReader alloc] initWithAsset:mAsset error:nil];

    [movieFile readNextVideoFrameFromOutput:mOutput];

    [mReader addOutput:mOutput];
    [mReader startReading];

    CMSampleBufferRef sampleBuffer=[mOutput copyNextSampleBuffer];

    CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
    CVPixelBufferLockBaseAddress( pixelBuffer, 0 );

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 600, 400, 0, GL_BGRA_EXT, GL_UNSIGNED_BYTE, CVPixelBufferGetBaseAddress( pixelBuffer ));
    CVPixelBufferUnlockBaseAddress( pixelBuffer, 0 );

    return sampleBuffer;
}

here in view did load

[super viewDidLoad];
NSMutableArray *arrImages=[[NSMutableArray alloc] init];

//    filter = [[GPUImagePixellateFilter alloc] init];
//    filter = [[GPUImageUnsharpMaskFilter alloc] init];

filter = [[GPUImageDissolveBlendFilter alloc] init];
[(GPUImageDissolveBlendFilter *)filter setMix:0.5];

sampleURL = [[NSBundle mainBundle] URLForResource:@"Sydney" withExtension:@"m4v"];
movieFile = [[GPUImageMovie alloc] initWithURL:sampleURL];
movieFile.runBenchmark = YES;
movieFile.playAtActualSpeed = YES;
[movieFile addTarget:filter];
[movieFile prepareForImageCapture];


[movieFile processMovieFrame:[self readMovieFrames]];

MPMoviePlayerController *player = [[MPMoviePlayerController alloc] initWithContentURL: sampleURL];
[player prepareToPlay];
[player.view setFrame: CGRectMake(0, 100, 320, 240)];  // player's frame must match parent's
[self.view addSubview: player.view];


AVPlayerItem *playerItem = [AVPlayerItem playerItemWithURL:sampleURL];
CMTime duration = playerItem.duration;
float seconds = CMTimeGetSeconds(duration);
NSLog(@"duration: %.2f", seconds);

[player play];

GPUImagePicture *overlayPicture;

for (int i=0; i<seconds; i++) {

    UIImage *image = [player thumbnailImageAtTime:i timeOption:MPMovieTimeOptionNearestKeyFrame];

    [arrImages addObject:image];

    overlayPicture= [[GPUImagePicture alloc] initWithImage:[arrImages objectAtIndex:i]];

    [overlayPicture addTarget:filter];

    [overlayPicture processImage];

    NSLog(@"Image  -0-0-0-0- %@",image);
    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
}

// Only rotate the video for display, leave orientation the same for recrding
GPUImageView *filterView = (GPUImageView *)self.view;
[filter addTarget:filterView];

// In addition to displaying to the screen, write out a processed version of the movie to disk
NSString *pathToMovie = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/EditedMovie.m4v"];
unlink([pathToMovie UTF8String]); // If a file already exists, AVAssetWriter won't let you record new frames, so delete the old movie
NSURL *movieURL = [NSURL fileURLWithPath:pathToMovie];

movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(640.0, 480.0)];
[filter addTarget:movieWriter];

// Configure this for video from the movie file, where we want to preserve all video frames and audio samples
movieWriter.shouldPassthroughAudio = YES;
movieFile.audioEncodingTarget = movieWriter;
[movieFile enableSynchronizedEncodingUsingMovieWriter:movieWriter];

[movieWriter startRecording];
[movieFile startProcessing];

[movieWriter setCompletionBlock:^{
    [filter removeTarget:movieWriter];
    [movieWriter finishRecording];
}];