第5月第14天 视频编辑

1.视频方向

+ (NSUInteger)degressFromVideoFileWithURL:(NSURL *)url
{
    NSUInteger degress = 0;
    AVAsset *asset = [AVAsset assetWithURL:url];
    NSArray *tracks = [asset tracksWithMediaType:AVMediaTypeVideo];
    if([tracks count] > 0) {
        AVAssetTrack *videoTrack = [tracks objectAtIndex:0];
        CGAffineTransform t = videoTrack.preferredTransform;
        if(t.a == 0 && t.b == 1.0 && t.c == -1.0 && t.d == 0){
            // Portrait
            degress = 90;
        }else if(t.a == 0 && t.b == -1.0 && t.c == 1.0 && t.d == 0){
            // PortraitUpsideDown
            degress = 270;
        }else if(t.a == 1.0 && t.b == 0 && t.c == 0 && t.d == 1.0){
            // LandscapeRight
            degress = 0;
        }else if(t.a == -1.0 && t.b == 0 && t.c == 0 && t.d == -1.0){
            // LandscapeLeft
            degress = 180;
        }
    }
    return degress;
}

 http://www.tuicool.com/articles/IjyUnmb

2.

  // 3.1 - Create AVMutableVideoCompositionInstruction
  AVMutableVideoCompositionInstruction *mainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
  mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, self.videoAsset.duration);

  // 3.2 - Create an AVMutableVideoCompositionLayerInstruction for the video track and fix the orientation.
  AVMutableVideoCompositionLayerInstruction *videolayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
  AVAssetTrack *videoAssetTrack = [[self.videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
  UIImageOrientation videoAssetOrientation_  = UIImageOrientationUp;
  BOOL isVideoAssetPortrait_  = NO;
  CGAffineTransform videoTransform = videoAssetTrack.preferredTransform;
  if (videoTransform.a == 0 && videoTransform.b == 1.0 && videoTransform.c == -1.0 && videoTransform.d == 0) {
    videoAssetOrientation_ = UIImageOrientationRight;
    isVideoAssetPortrait_ = YES;
  }
  if (videoTransform.a == 0 && videoTransform.b == -1.0 && videoTransform.c == 1.0 && videoTransform.d == 0) {
    videoAssetOrientation_ =  UIImageOrientationLeft;
    isVideoAssetPortrait_ = YES;
  }
  if (videoTransform.a == 1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == 1.0) {
    videoAssetOrientation_ =  UIImageOrientationUp;
  }
  if (videoTransform.a == -1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == -1.0) {
    videoAssetOrientation_ = UIImageOrientationDown;
  }
  [videolayerInstruction setTransform:videoAssetTrack.preferredTransform atTime:kCMTimeZero];
  [videolayerInstruction setOpacity:0.0 atTime:self.videoAsset.duration];

  // 3.3 - Add instructions
  mainInstruction.layerInstructions = [NSArray arrayWithObjects:videolayerInstruction,nil];

  AVMutableVideoComposition *mainCompositionInst = [AVMutableVideoComposition videoComposition];

  CGSize naturalSize;
  if(isVideoAssetPortrait_){
    naturalSize = CGSizeMake(videoAssetTrack.naturalSize.height, videoAssetTrack.naturalSize.width);
  } else {
    naturalSize = videoAssetTrack.naturalSize;
  }

  float renderWidth, renderHeight;
  renderWidth = naturalSize.width;
  renderHeight = naturalSize.height;
  mainCompositionInst.renderSize = CGSizeMake(renderWidth, renderHeight);
  mainCompositionInst.instructions = [NSArray arrayWithObject:mainInstruction];
  mainCompositionInst.frameDuration = CMTimeMake(1, 30);

  [self applyVideoEffectsToComposition:mainCompositionInst size:naturalSize];

- (void)applyVideoEffectsToComposition:(AVMutableVideoComposition *)composition size:(CGSize)size
{
  // 1 - set up the overlay
  CALayer *overlayLayer = [CALayer layer];
  UIImage *overlayImage = nil;
  if (_frameSelectSegment.selectedSegmentIndex == 0) {
    overlayImage = [UIImage imageNamed:@"Frame-1.png"];
  } else if(_frameSelectSegment.selectedSegmentIndex == 1) {
    overlayImage = [UIImage imageNamed:@"Frame-2.png"];
  } else if(_frameSelectSegment.selectedSegmentIndex == 2) {
    overlayImage = [UIImage imageNamed:@"Frame-3.png"];
  }
 
  [overlayLayer setContents:(id)[overlayImage CGImage]];
  overlayLayer.frame = CGRectMake(0, 0, size.width, size.height);
  [overlayLayer setMasksToBounds:YES];
 
  // 2 - set up the parent layer
  CALayer *parentLayer = [CALayer layer];
  CALayer *videoLayer = [CALayer layer];
  parentLayer.frame = CGRectMake(0, 0, size.width, size.height);
  videoLayer.frame = CGRectMake(0, 0, size.width, size.height);
  [parentLayer addSublayer:videoLayer];
  [parentLayer addSublayer:overlayLayer];
 
  // 3 - apply magic
  composition.animationTool = [AVVideoCompositionCoreAnimationTool
                               videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];

}

http://www.cocoachina.com/ios/20141208/10542.html