我正在尝试合并两个原本位于不同方向的视频。
视频A - 纵向方向 - 720x1280 - MOV 视频B - 横向方向 - 640x480 - MP4
我首先要调整视频A并进行裁剪
- (void)resizeWithStyle:(NSString*)style {
NSString *filePath = [self.lastVideo path];
NSString *newPath = [filePath stringByReplacingOccurrencesOfString:@".mov" withString:@".mp4"];
NSURL *fullPath = [NSURL fileURLWithPath:newPath];
NSURL *path = [NSURL fileURLWithPath:filePath];
NSDictionary *options = @{ AVURLAssetPreferPreciseDurationAndTimingKey : @YES };
AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:self.lastVideo options:options];
NSInteger width = 640;
NSInteger height = 480;
if (([self orientationForTrack:asset] == UIInterfaceOrientationPortrait) || ([self orientationForTrack:asset] == UIInterfaceOrientationPortraitUpsideDown)) {
width = 480;
height = 640;
}
NSLog(@"Write Started");
NSError *error = nil;
NSString *styleKey = AVVideoScalingModeResizeAspectFill;
if ([style isEqualToString:@"fit"]) {
styleKey = AVVideoScalingModeResizeAspect;
}
AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:fullPath fileType:AVFileTypeQuickTimeMovie error:&error];
NSParameterAssert(videoWriter);
AVAsset *avAsset = [[AVURLAsset alloc] initWithURL:path options:nil];
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:width], AVVideoWidthKey,
[NSNumber numberWithInt:height], AVVideoHeightKey,
styleKey, AVVideoScalingModeKey,
nil];
AVAssetWriterInput* videoWriterInput = [AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoSettings];
NSParameterAssert(videoWriterInput);
NSParameterAssert([videoWriter canAddInput:videoWriterInput]);
videoWriterInput.expectsMediaDataInRealTime = YES;
[videoWriter addInput:videoWriterInput];
NSError *aerror = nil;
AVAssetReader *reader = [[AVAssetReader alloc] initWithAsset:avAsset error:&aerror];
AVAssetTrack *videoTrack = [[avAsset tracksWithMediaType:AVMediaTypeVideo]objectAtIndex:0];
videoWriterInput.transform = videoTrack.preferredTransform;
NSDictionary *videoOptions = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
AVAssetReaderTrackOutput *asset_reader_output = [[AVAssetReaderTrackOutput alloc] initWithTrack:videoTrack outputSettings:videoOptions];
[reader addOutput:asset_reader_output];
//audio setup
AVAssetWriterInput* audioWriterInput = [AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeAudio
outputSettings:nil];
AVAssetReader *audioReader = [AVAssetReader assetReaderWithAsset:avAsset error:&error];
AVAssetTrack* audioTrack = [[avAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
AVAssetReaderOutput *readerOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:audioTrack outputSettings:nil];
[audioReader addOutput:readerOutput];
NSParameterAssert(audioWriterInput);
NSParameterAssert([videoWriter canAddInput:audioWriterInput]);
audioWriterInput.expectsMediaDataInRealTime = NO;
[videoWriter addInput:audioWriterInput];
[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:kCMTimeZero];
[reader startReading];
dispatch_queue_t _processingQueue = dispatch_queue_create("assetAudioWriterQueue", NULL);
[videoWriterInput requestMediaDataWhenReadyOnQueue:_processingQueue usingBlock:
^{
while ([videoWriterInput isReadyForMoreMediaData]) {
CMSampleBufferRef sampleBuffer;
if ([reader status] == AVAssetReaderStatusReading &&
(sampleBuffer = [asset_reader_output copyNextSampleBuffer])) {
BOOL result = [videoWriterInput appendSampleBuffer:sampleBuffer];
CFRelease(sampleBuffer);
if (!result) {
[reader cancelReading];
break;
}
} else {
[videoWriterInput markAsFinished];
switch ([reader status]) {
case AVAssetReaderStatusReading:
// the reader has more for other tracks, even if this one is done
break;
case AVAssetReaderStatusFailed:
[videoWriter cancelWriting];
break;
case AVAssetReaderStatusCompleted:
// your method for when the conversion is done
// should call finishWriting on the writer
//hook up audio track
[audioReader startReading];
[videoWriter startSessionAtSourceTime:kCMTimeZero];
dispatch_queue_t mediaInputQueue = dispatch_queue_create("mediaInputQueue", NULL);
[audioWriterInput requestMediaDataWhenReadyOnQueue:mediaInputQueue usingBlock:^
{
NSLog(@"Request");
NSLog(@"Asset Writer ready :%d",audioWriterInput.readyForMoreMediaData);
while (audioWriterInput.readyForMoreMediaData) {
CMSampleBufferRef nextBuffer;
if ([audioReader status] == AVAssetReaderStatusReading &&
(nextBuffer = [readerOutput copyNextSampleBuffer])) {
NSLog(@"Ready");
if (nextBuffer) {
NSLog(@"NextBuffer");
[audioWriterInput appendSampleBuffer:nextBuffer];
}
}else{
[audioWriterInput markAsFinished];
switch ([audioReader status]) {
case AVAssetReaderStatusCompleted:
[videoWriter finishWritingWithCompletionHandler:^{
if (videoWriter.status != AVAssetWriterStatusFailed && videoWriter.status == AVAssetWriterStatusCompleted) {
NSLog(@"Asset written");
NSLog(@"New Asset Orienatation: %d", [self orientationForTrack:asset]);
[self checkFileExists:fullPath];
[self getVideoProperties:fullPath];
self.lastVideo = fullPath;
//[self showDocumentsContents];
self.libraryVideo = fullPath;
} else {
}
}];
break;
}
}
}
}
];
break;
}
break;
}
}
}
];
NSLog(@"Write Ended");
}
此外观效果很好，看起来与我想要的能够在H264（mp4）格式中填充或适合640x480。当在MPMoviePlayerController中播放时，视频现在呈现为横向格式。
接下来，我正尝试加入这两个视频。
- (void)joinVideo:(id)sender {
if ((self.libraryVideo != nil) && (self.recordVideo != nil)) {
NSString *libraryPath = [self.libraryVideo path];
NSString *outputPath = [libraryPath stringByReplacingOccurrencesOfString:@".mp4" withString:@"-joined.mp4"];
NSURL *outputURL = [NSURL fileURLWithPath:outputPath];
NSLog(@"Can Merge Video");
NSMutableArray *audioTracks = [NSMutableArray array];
NSMutableArray *videoTracks = [NSMutableArray array];
NSDictionary *options = @{ AVURLAssetPreferPreciseDurationAndTimingKey : @YES };
AVURLAsset *asset2 = [AVURLAsset URLAssetWithURL:self.recordVideo options:options];
[videoTracks addObjectsFromArray:[asset2 tracksWithMediaType:AVMediaTypeVideo]];
[audioTracks addObjectsFromArray:[asset2 tracksWithMediaType:AVMediaTypeAudio]];
NSLog(@"Asset 2 Orienatation: %d", [self orientationForTrack:asset2]);
AVURLAsset *asset1 = [AVURLAsset URLAssetWithURL:self.libraryVideo options:options];
[videoTracks addObjectsFromArray:[asset1 tracksWithMediaType:AVMediaTypeVideo]];
[audioTracks addObjectsFromArray:[asset1 tracksWithMediaType:AVMediaTypeAudio]];
NSLog(@"Asset 1 Orienatation: %d", [self orientationForTrack:asset1]);
AVMutableComposition *composition = [[AVMutableComposition alloc] init];
AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];
videoComposition.frameDuration = CMTimeMake(1,30);
videoComposition.renderScale = 1.0;
if ([audioTracks count] > 0) {
AVMutableCompositionTrack * audioTrackComposition = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[audioTracks enumerateObjectsUsingBlock:^(AVAssetTrack *track, NSUInteger idx, BOOL *stop) {
[audioTrackComposition insertTimeRange:CMTimeRangeMake(kCMTimeZero, track.timeRange.duration)
ofTrack:track
atTime:kCMTimeZero
error:nil];
}];
}
AVMutableCompositionTrack *videoTrackComposition = [composition addMutableTrackWithMediaType:AVMediaTypeVideo
preferredTrackID:kCMPersistentTrackID_Invalid];
[videoTracks enumerateObjectsUsingBlock:^(AVAssetTrack *track, NSUInteger idx, BOOL *stop) {
[videoTrackComposition insertTimeRange:CMTimeRangeMake(kCMTimeZero, track.timeRange.duration)
ofTrack:track
atTime:kCMTimeZero
error:nil];
}];
AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
AVMutableVideoCompositionLayerInstruction *layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrackComposition];
AVAssetTrack *sourceVideoTrack = [[asset2 tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
CGAffineTransform rotationTransform = CGAffineTransformMakeRotation(M_PI/2);
CGAffineTransform rotateTranslate = CGAffineTransformTranslate(rotationTransform,320,0);
[videoTrackComposition setPreferredTransform:sourceVideoTrack.preferredTransform];
[layerInstruction setTransform:rotateTranslate atTime:kCMTimeZero];
instruction.layerInstructions = [NSArray arrayWithObject: layerInstruction];
videoComposition.instructions = [NSArray arrayWithObject: instruction];
AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:composition
presetName:AVAssetExportPresetPassthrough];
exportSession.outputFileType = AVFileTypeMPEG4;
exportSession.shouldOptimizeForNetworkUse = YES;
exportSession.outputURL = outputURL;
[exportSession exportAsynchronouslyWithCompletionHandler:^ {
switch (exportSession.status) {
case AVAssetExportSessionStatusFailed: {
NSLog(@"Join Failed");
break;
}
case AVAssetExportSessionStatusCompleted: {
NSLog(@"Join Completed");
[self checkFileExists:outputURL];
[self getVideoProperties:outputURL];
self.lastVideo = outputURL;
break;
}
case AVAssetExportSessionStatusCancelled: {
NSLog(@"Join Cancelled");
break;
}
default:
break;
}
}];
}
}
这成功加入了视频。但是，视频A现在旋转90度，而视频B看起来正确。
我花了很多时间试图弄清楚为什么在这次合并中，视频A没有被视为真正的风景视频640x480。我试图在视频A上运行单独的操作来强制进行preferredTransform更改，但它似乎没有做任何事情。此外，在原始AVAssetWriterInput上设置首选变换似乎也没有影响。
任何真正有效的想法？我尝试过的所有内容都以Video A旋转90度并在合并时拉伸。
有没有办法强制对照片库的输入进行定位？
谢谢！