Iphone 使用UIImage和caf创建视频文件时出现问题

我已经阅读了互联网上所有关于这个功能的帖子，我在创建视频文件方面取得了一些成功，但我还有3个问题，似乎没有人提到过

我有三个问题：

某些播放器无法正确播放视频：quicktime（窗口），视频仅播放一帧，屏幕变为白色，视频无法在youtube上播放

有些图像，由于某种原因，图像很不正常

（好的，他们说我是新用户，不允许我在帖子中发布图片。）

有些图像，由于某种原因，方向不正确，即使我根据方向转换了上下文，它仍然不起作用

有人能帮我一下吗？非常感谢

这是我的密码：

1：使用此功能创建带有UIImage的视频，我只使用了一个图像和一个音频文件（caf），我希望在播放音频时显示该图像

- (void)writeImageAndAudioAsMovie:(UIImage*)image andAudio:(NSString *)audioFilePath duration:(int)duration {
    NSLog(@"start make movie: length:%d",duration);
    NSError *error = nil;
    AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:ImageVideoPath] fileType:AVFileTypeMPEG4
                                                          error:&error];
    NSParameterAssert(videoWriter);
    if ([[NSFileManager defaultManager] fileExistsAtPath:ImageVideoPath]) 
        [[NSFileManager defaultManager] removeItemAtPath:ImageVideoPath error:nil];

    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecH264, AVVideoCodecKey,
                               [NSNumber numberWithInt:image.size.width],AVVideoWidthKey,[NSNumber numberWithInt:image.size.height], AVVideoHeightKey,nil];
    AVAssetWriterInput* writerInput = [[AVAssetWriterInput
                                    assetWriterInputWithMediaType:AVMediaTypeVideo
                                    outputSettings:videoSettings] retain];

    AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput sourcePixelBufferAttributes:nil];
    NSParameterAssert(writerInput);
    NSParameterAssert([videoWriter canAddInput:writerInput]);
    writerInput.expectsMediaDataInRealTime = YES;
    [videoWriter setShouldOptimizeForNetworkUse:YES];
    [videoWriter addInput:writerInput];

    //Start a session:
    [videoWriter startWriting];
    [videoWriter startSessionAtSourceTime:kCMTimeZero];

    //Write samples:
    CVPixelBufferRef buffer = [self pixelBufferFromCGImage:image.CGImage];
    [adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];

    //Finish the session:
    [videoWriter endSessionAtSourceTime:CMTimeMake(duration, 1)];
    [writerInput markAsFinished];
    [videoWriter finishWriting];

    CVPixelBufferPoolRelease(adaptor.pixelBufferPool);
    [videoWriter release];
    [writerInput release];
    [self addAudioToFileAtPath:ImageVideoPath andAudioPath:audioFilePath];
}

二,。为视频创建CVPixelBufferRef

-(CVPixelBufferRef)pixelBufferFromCGImage: (CGImageRef) image{
    float width = CGImageGetWidth(cgimage);
    float height = CGImageGetHeight(cgimage);

    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                         [NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
                         [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
                         nil];
    CVPixelBufferRef pxbuffer = NULL;
    CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, width,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,width,height,8,4*width,rgbColorSpace,kCGImageAlphaNoneSkipFirst);

    NSParameterAssert(context);
    CGContextDrawImage(context, CGRectMake(0, 0,width, height), cgimage);

    CGColorSpaceRelease(rgbColorSpace);
    CGContextRelease(context);

    CVPixelBufferUnlockBaseAddress(pxbuffer, 0);

    return pxbuffer;
}

三,。将视频和音频放在一起

-(void) addAudioToFileAtPath:(NSString *)vidoPath andAudioPath:(NSString *)audioPath{
    AVMutableComposition* mixComposition = [AVMutableComposition composition];

    NSURL* audio_inputFileUrl = [NSURL fileURLWithPath:audioPath];
    NSURL* video_inputFileUrl = [NSURL fileURLWithPath:vidoPath];

    NSString *outputFilePath = FinalVideoPath;
    NSURL* outputFileUrl = [NSURL fileURLWithPath:outputFilePath];

    if ([[NSFileManager defaultManager] fileExistsAtPath:outputFilePath]) 
        [[NSFileManager defaultManager] removeItemAtPath:outputFilePath error:nil];

    AVURLAsset* audioAsset = [[AVURLAsset alloc]initWithURL:audio_inputFileUrl options:nil];
    CMTimeRange audio_timeRange = CMTimeRangeMake(kCMTimeZero, audioAsset.duration);
    AVMutableCompositionTrack *b_compositionAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
    [b_compositionAudioTrack insertTimeRange:audio_timeRange ofTrack:[[audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];


    AVURLAsset* videoAsset = [[AVURLAsset alloc]initWithURL:video_inputFileUrl options:nil];
    CMTimeRange video_timeRange = CMTimeRangeMake(kCMTimeZero,videoAsset.duration);
    AVMutableCompositionTrack *a_compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
    [a_compositionVideoTrack insertTimeRange:video_timeRange ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:kCMTimeZero error:nil];

    //nextClipStartTime = CMTimeAdd(nextClipStartTime, a_timeRange.duration);
    [audioAsset release];audioAsset = nil;
    [videoAsset release];videoAsset = nil;

    AVAssetExportSession* _assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];   
    _assetExport.outputFileType = AVFileTypeQuickTimeMovie;
    _assetExport.outputURL = outputFileUrl;

    [_assetExport exportAsynchronouslyWithCompletionHandler:
     ^(void ) {
         switch (_assetExport.status) 
         {
             case AVAssetExportSessionStatusCompleted:
                 //export complete 
                 NSLog(@"Export Complete");
                 break;
             case AVAssetExportSessionStatusFailed:
                 NSLog(@"Export Failed");
                 NSLog(@"ExportSessionError: %@", [_assetExport.error localizedDescription]);
             //export error (see exportSession.error)  
                 break;
             case AVAssetExportSessionStatusCancelled:
                 NSLog(@"Export Failed");
                 NSLog(@"ExportSessionError: %@", [_assetExport.error localizedDescription]);
                 //export cancelled  
                 break;
         }
      }];    
}

---

有这个问题。以下是您希望修复的复选标记列表：

1） 视频不能有alpha通道，因此您的像素缓冲区应该如下所示

static OSType pixelFormatType = kCVPixelFormatType_32ARGB;


- (CVPixelBufferRef)pixelBufferFromCGImage:(CGImageRef)image {
    CGSize frameSize = CGSizeMake(CGImageGetWidth(image), CGImageGetHeight(image));
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                             @YES, kCVPixelBufferCGImageCompatibilityKey,
                             @YES, kCVPixelBufferCGBitmapContextCompatibilityKey,
                             nil];
    CVPixelBufferRef pxbuffer = NULL;
    CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault,
                                          frameSize.width,
                                          frameSize.height,
                                          pixelFormatType,
                                          (__bridge CFDictionaryRef)options,
                                          &pxbuffer);
    NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);

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

    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
    CGBitmapInfo bitmapInfo = kCGImageAlphaNoneSkipFirst & kCGBitmapAlphaInfoMask;

    //NSUInteger bytesPerRow = 4 * frameSize.width;
    NSUInteger bitsPerComponent = 8;
    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(pxbuffer);

    CGContextRef context = CGBitmapContextCreate(pxdata,
                                                 frameSize.width,
                                                 frameSize.height,
                                                 bitsPerComponent,
                                                 bytesPerRow,
                                                 rgbColorSpace,
                                                 bitmapInfo);

    CGContextDrawImage(context, CGRectMake(0, 0, frameSize.width, frameSize.height), image);
    CGColorSpaceRelease(rgbColorSpace);
    CGContextRelease(context);

    CVPixelBufferUnlockBaseAddress(pxbuffer, 0);

    return pxbuffer;
}

NSMutableDictionary *attributes = [[NSMutableDictionary alloc] init];
[attributes setObject:[NSNumber numberWithUnsignedInt:pixelFormatType] forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:imageSize.width] forKey:(NSString*)kCVPixelBufferWidthKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:imageSize.height] forKey:(NSString*)kCVPixelBufferHeightKey];

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

2） 确保您正在真实的设备上进行测试。模拟器会使视频失真，我在使用模拟器制作视频时也遇到了同样的问题

3） 确保像这样创建AvassetWriterInputPixelBufferAdapter

static OSType pixelFormatType = kCVPixelFormatType_32ARGB;


- (CVPixelBufferRef)pixelBufferFromCGImage:(CGImageRef)image {
    CGSize frameSize = CGSizeMake(CGImageGetWidth(image), CGImageGetHeight(image));
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                             @YES, kCVPixelBufferCGImageCompatibilityKey,
                             @YES, kCVPixelBufferCGBitmapContextCompatibilityKey,
                             nil];
    CVPixelBufferRef pxbuffer = NULL;
    CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault,
                                          frameSize.width,
                                          frameSize.height,
                                          pixelFormatType,
                                          (__bridge CFDictionaryRef)options,
                                          &pxbuffer);
    NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);

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

    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
    CGBitmapInfo bitmapInfo = kCGImageAlphaNoneSkipFirst & kCGBitmapAlphaInfoMask;

    //NSUInteger bytesPerRow = 4 * frameSize.width;
    NSUInteger bitsPerComponent = 8;
    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(pxbuffer);

    CGContextRef context = CGBitmapContextCreate(pxdata,
                                                 frameSize.width,
                                                 frameSize.height,
                                                 bitsPerComponent,
                                                 bytesPerRow,
                                                 rgbColorSpace,
                                                 bitmapInfo);

    CGContextDrawImage(context, CGRectMake(0, 0, frameSize.width, frameSize.height), image);
    CGColorSpaceRelease(rgbColorSpace);
    CGContextRelease(context);

    CVPixelBufferUnlockBaseAddress(pxbuffer, 0);

    return pxbuffer;
}

NSMutableDictionary *attributes = [[NSMutableDictionary alloc] init];
[attributes setObject:[NSNumber numberWithUnsignedInt:pixelFormatType] forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:imageSize.width] forKey:(NSString*)kCVPixelBufferWidthKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:imageSize.height] forKey:(NSString*)kCVPixelBufferHeightKey];

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

---

我仍然有一些其他问题，但不是扭曲的视频或定向问题。如果您没有直接从asset请求缩略图图像，则需要将图像旋转到正确的方向。

我可以帮助您解决方向问题，请参阅我的帖子“你是上帝”的答案。我只有在图像处于纵向模式时才出现问题&横向效果良好。我找出了问题，我发现实际的问题是在阿尔法设置中。谢谢