从视频中 取得每一帧 处理 写入文件

- (void)merge{

    // 视频源路径

    _videoPath = @"/Users/liter/Desktop/IMG_2546.m4v";

    // 新视频路径

    _path = @"/Users/liter/Desktop/123.m4v";

    // 读

    [self setupAssetReader];

   // 写

　　[self setupAssetWriter];

    

    

    

    

    // 读其他视频 的音频 

    AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:@"/Users/liter/Desktop/IMG_2545.m4v"] options:nil];

    AVAssetReader *readerTwo = [[AVAssetReader alloc] initWithAsset:asset error:nil];

    

    AVAssetTrack *audioTrack = [[asset tracksWithMediaType:AVMediaTypeAudio] firstObject];

    NSDictionary *dic = @{AVFormatIDKey :@(kAudioFormatLinearPCM),

                          AVLinearPCMIsBigEndianKey:@NO,

                          AVLinearPCMIsFloatKey:@NO,

                          AVLinearPCMBitDepthKey :@(16)

                          };

    AVAssetReaderTrackOutput *trackOutputTwo = [[AVAssetReaderTrackOutput alloc]initWithTrack:audioTrack outputSettings:dic];

    [readerTwo addOutput:trackOutputTwo];

    

    

    //音频的一些配置包括音频各种这里为AAC,音频通道、采样率和音频的比特率

    NSDictionary *audioSettings = [NSDictionary dictionaryWithObjectsAndKeys:

                                   [ NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey,

                                   [ NSNumber numberWithInt: 1], AVNumberOfChannelsKey,

                                   [ NSNumber numberWithFloat: 44100], AVSampleRateKey,

                                   [ NSNumber numberWithInt: 128000], AVEncoderBitRateKey,

                                   nil];

    //初始化音频写入类

    AVAssetWriterInput *audioInputTwo = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:audioSettings];

    //表明输入是否应该调整其处理为实时数据源的数据

    audioInputTwo.expectsMediaDataInRealTime = YES;

    //将音频输入源加入

    [_assetWriter addInput:audioInputTwo];

    

    

    

    // 加入 额外的 音频 

    [readerTwo startReading];

    

    

    

    

    

    

    

    

    

    

    [_reader startReading];

    [_assetWriter startWriting];

    [_assetWriter startSessionAtSourceTime:kCMTimeZero];

    

    NSLog(@"开始");

    while ([_reader status] == AVAssetReaderStatusReading  ) {

        CMSampleBufferRef videoBuffer = [_videoReaderOutput copyNextSampleBuffer];

        CMSampleBufferRef audioBuffer = [_audioReaderOutput copyNextSampleBuffer];

        

        

        CMSampleBufferRef audioBufferTwo = [trackOutputTwo copyNextSampleBuffer];

        

        // buffer 转图片

        UIImage *image = [self imageFromSampleBuffer:videoBuffer];

        if (image == nil) {

            continue;

        }

　　　　// 在这可对这一帧图片 做处理 

        //        UIImage *newImage = [self addFiliterFrom:image filiterImage:_filiterImage];

        // 转回可写入的buffer

        CVPixelBufferRef buffer = (CVPixelBufferRef)[self pixelBufferFromCGImage:[image CGImage] size:CGSizeMake(image.size.width, image.size.height)];

        if (buffer)

        {

            while (!_videoInput.isReadyForMoreMediaData || !_audioInput.isReadyForMoreMediaData || !audioInputTwo.isReadyForMoreMediaData) {

                usleep(1);

            }

            CMTime startTime = CMSampleBufferGetPresentationTimeStamp(videoBuffer);

            if (audioBuffer) {

                [_audioInput appendSampleBuffer:audioBuffer];

                

                [audioInputTwo appendSampleBuffer:audioBufferTwo];

                

            }

            if(![_adaptor appendPixelBuffer:buffer withPresentationTime:startTime])

                NSLog(@"FAIL");

            CFRelease(buffer);

        }

    }

    //    [readerTwo cancelReading];

    //    __weak JBAssetReader *weakSelf = self;

    [_assetWriter finishWritingWithCompletionHandler:^{

        NSLog(@"完成");

        //        if (weakSelf.delegate) {

        //            [weakSelf.delegate videoPath:_path];

        //        }

    }];

    NSLog(@"...");

}

- (void)setupAssetReader {

    

    

    AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:_videoPath] options:nil];

    _reader = [[AVAssetReader alloc] initWithAsset:asset error:nil];

    AVAssetTrack *videoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] firstObject];

    

    

    int m_pixelFormatType = kCVPixelFormatType_32BGRA;

    NSMutableDictionary *options = [NSMutableDictionary dictionary];

    [options setObject:@(m_pixelFormatType) forKey:(id)kCVPixelBufferPixelFormatTypeKey];

    

    _videoReaderOutput = [[AVAssetReaderTrackOutput alloc] initWithTrack:videoTrack outputSettings:options];

    

    [_reader addOutput:_videoReaderOutput];

    

    

    

    AVAssetTrack *audioTrack = [[asset tracksWithMediaType:AVMediaTypeAudio] firstObject];

    NSDictionary *dic = @{AVFormatIDKey :@(kAudioFormatLinearPCM),

                          AVLinearPCMIsBigEndianKey:@NO,

                          AVLinearPCMIsFloatKey:@NO,

                          AVLinearPCMBitDepthKey :@(16)

                          };

    _audioReaderOutput = [[AVAssetReaderTrackOutput alloc]initWithTrack:audioTrack outputSettings:dic];

    [_reader addOutput:_audioReaderOutput];

    

    

    

}

- (void)setupAssetWriter {

    _assetWriter = [AVAssetWriter assetWriterWithURL:[NSURL fileURLWithPath:_path] fileType:AVFileTypeMPEG4 error:nil];

    [[NSFileManager defaultManager] removeItemAtPath:_path error:nil];

    NSParameterAssert(_assetWriter);

    //录制视频的一些配置，分辨率，编码方式等等

    NSDictionary* videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:

                                   AVVideoCodecH264, AVVideoCodecKey,

                                   [NSNumber numberWithInteger: 480], AVVideoWidthKey,

                                   [NSNumber numberWithInteger: 480], AVVideoHeightKey,

                                   nil];

    _videoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];

    _videoInput.expectsMediaDataInRealTime = YES;

    

    

    NSParameterAssert(_videoInput);

    NSParameterAssert([_assetWriter canAddInput:_videoInput]);

    //将视频输入源加入

    [_assetWriter addInput:_videoInput];

    

    

    NSDictionary *sourcePixelBufferAttributesDictionary = [NSDictionary dictionaryWithObjectsAndKeys:

                                                           [NSNumber numberWithInt:kCVPixelFormatType_32BGRA], kCVPixelBufferPixelFormatTypeKey, nil];

    

    _adaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:_videoInput

                                                                                sourcePixelBufferAttributes:sourcePixelBufferAttributesDictionary];

    //音频的一些配置包括音频各种这里为AAC,音频通道、采样率和音频的比特率

    NSDictionary *audioSettings = [NSDictionary dictionaryWithObjectsAndKeys:

                                   [ NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey,

                                   [ NSNumber numberWithInt: 1], AVNumberOfChannelsKey,

                                   [ NSNumber numberWithFloat: 44100], AVSampleRateKey,

                                   [ NSNumber numberWithInt: 128000], AVEncoderBitRateKey,

                                   nil];

    //初始化音频写入类

    _audioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:audioSettings];

    //表明输入是否应该调整其处理为实时数据源的数据

    _audioInput.expectsMediaDataInRealTime = YES;

    //将音频输入源加入

    [_assetWriter addInput:_audioInput];

    

    

}