如何从iPhone框架创建视频

Question

我已经完成了研发工作并取得了成功,如何根据播放的视频文件中的图像获取帧MPMoviePlayerController.

从此代码中获取所有帧,并将所有图像保存在一个阵列中.

for(int i= 1; i <= moviePlayerController.duration; i++)
{
    UIImage *img = [moviePlayerController thumbnailImageAtTime:i timeOption:MPMovieTimeOptionNearestKeyFrame];
    [arrImages addObject:img];
}

现在的问题是,在更改了一些图像文件后,比如为图像添加情感并添加过滤器,例如; 电影真实,黑白,我们如何再次创建视频并以相同的帧速率将相同的视频存储在文档目录中,而不会丢失视频质量.

更改了一些图像后,我按照代码再次保存了该视频.

- (void) writeImagesAsMovie:(NSString*)path 
{
    NSError *error  = nil;
    UIImage *first = [arrImages objectAtIndex:0];
    CGSize frameSize = first.size;
    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
                                  [NSURL fileURLWithPath:path] fileType:AVFileTypeQuickTimeMovie
                                                              error:&error];
    NSParameterAssert(videoWriter);

    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                   AVVideoCodecH264, AVVideoCodecKey,
                                   [NSNumber numberWithInt:640], AVVideoWidthKey,
                                   [NSNumber numberWithInt:480], AVVideoHeightKey,
                                   nil];
    AVAssetWriterInput* writerInput = [[AVAssetWriterInput
                                        assetWriterInputWithMediaType:AVMediaTypeVideo
                                        outputSettings:videoSettings] retain];

    AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor
                                                     assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput
                                                     sourcePixelBufferAttributes:nil];

    NSParameterAssert(writerInput);
    NSParameterAssert([videoWriter canAddInput:writerInput]);
    [videoWriter addInput:writerInput];

    [videoWriter startWriting];
    [videoWriter startSessionAtSourceTime:kCMTimeZero];

    int frameCount = 0;
    CVPixelBufferRef buffer = NULL;
    for(UIImage *img in arrImages)
    {
        buffer = [self newPixelBufferFromCGImage:[img CGImage] andFrameSize:frameSize]; 

            if (adaptor.assetWriterInput.readyForMoreMediaData) 
            {
                CMTime frameTime = CMTimeMake(frameCount,(int32_t) kRecordingFPS);
                [adaptor appendPixelBuffer:buffer withPresentationTime:frameTime];

                if(buffer)
                    CVBufferRelease(buffer);
            }
        frameCount++;
    } 

     [writerInput markAsFinished];
     [videoWriter finishWriting];
}


- (CVPixelBufferRef) newPixelBufferFromCGImage: (CGImageRef) image andFrameSize:(CGSize)frameSize
{
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                             [NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
                             [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
                             nil];
    CVPixelBufferRef pxbuffer = NULL;
    CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, frameSize.width,
                                          frameSize.height, kCVPixelFormatType_32ARGB, (CFDictionaryRef) options, 
                                          &pxbuffer);
    NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);

    CVPixelBufferLockBaseAddress(pxbuffer, 0);
    void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
    NSParameterAssert(pxdata != NULL);

    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(pxdata, frameSize.width,
                                                 frameSize.height, 8, 4*frameSize.width, rgbColorSpace, 
                                                 kCGImageAlphaNoneSkipFirst);
    NSParameterAssert(context);
    CGContextConcatCTM(context, CGAffineTransformMakeRotation(0));
    CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image), 
                                           CGImageGetHeight(image)), image);
    CGColorSpaceRelease(rgbColorSpace);
    CGContextRelease(context);

    CVPixelBufferUnlockBaseAddress(pxbuffer, 0);

    return pxbuffer;
}

我是这个话题的新手,所以请帮我解决这个问题.

Answer 1

您可以参考以下链接,希望您能得到一些帮助: -

1. http://www.iphonedevsdk.com/forum/iphone-sdk-development-advanced-discussion/77999-make-video-nsarray-uiimages.html

2. 使用带有iPhone SDK的FFMPEG库进行视频编码

3. Iphone SDK,从UIImage创建视频

4. iOS视频编辑 - 是否可以使用iOS 4 AVFoundation类将两个视频文件合并(并排而不是一个接一个)？