Merge videos with transparent channels in iOS-

Merge videos with transparent channels in iOS-

 

So we are merging snow, lighting, and blasting... A video with a transparent channel is required.
Here I am using the GPUImage tool. We can talk about the seamless combination of snowflakes. Here, we 'd better use a bit of ps. when processing the image filter, you can use ps to check the parameters and effects.
Through the ps experiment, we found that the filter color can achieve this. GPUImageScreenBlendFilter can end this issue.
Detailed GPUImage header file click here ---- http://blog.csdn.net/think_ma/article/details/43093331
Not to mention code _ movieFile = [[GPUImageMovie alloc] initWithURL: url];

    _movieFile.runBenchmark = YES;    _movieFile.playAtActualSpeed = NO;    _movieFile2 = [[GPUImageMovie alloc] initWithURL:url2];    _movieFile2.runBenchmark = YES;    _movieFile2.playAtActualSpeed = NO;    _filter = [[GPUImageScreenBlendFilter alloc] init];    //    filter = [[GPUImageUnsharpMaskFilter alloc] init];    [_movieFile addTarget:self.filter];    [_movieFile2 addTarget:self.filter];    // Only rotate the video for display, leave orientation the same for recording    // In addition to displaying to the screen, write out a processed version of the movie to disk    NSString *pathToMovie = [NSHomeDirectory() stringByAppendingPathComponent:@Documents/last.mov];    unlink([pathToMovie UTF8String]); // If a file already exists, AVAssetWriter won't let you record new frames, so delete the old movie        NSLog(@file = %@,pathToMovie);    NSURL *movieURL = [NSURL fileURLWithPath:pathToMovie];        self.movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(640.0, 360.0)];    [self.filter addTarget:self.movieWriter];    // Configure this for video from the movie file, where we want to preserve all video frames and audio samples    self.movieWriter.shouldPassthroughAudio = YES;    //movieFile.audioEncodingTarget = self.movieWriter;    [_movieFile enableSynchronizedEncodingUsingMovieWriter:self.movieWriter];        [self.movieWriter startRecording];    [_movieFile startProcessing];    [_movieFile2 startProcessing];    __block mlkiMovie * sself = self;        [self.movieWriter setCompletionBlock:^{        [sself.filter removeTarget:sself.movieWriter];        [sself.movieFile endProcessing];        [sself.movieFile2 endProcessing];        [sself.movieWriter finishRecording];        NSLog(@ok);    }];

GPUImageScreenBlendFilter is equivalent to a ps filter.