[英]Merging *.mp3 with *.mov file using AVAssetReader and AVAssetWriter
[英]AVAssetReader / AVAssetWriter Join mp4 file with different resolutions
我正在編寫一個iPad應用程序,其中需要以不同的分辨率加入mp4文件。 為此,我結合使用AVAssetReader來讀取mp4源文件和AVAssetWriter來將這些源文件寫入單個mp4輸出文件中。
我嘗試使用AVAssetExportSession,但是我遇到的問題是,不同的連接文件之間存在黑框。
我現在面臨的問題是,一切似乎都很好,但是從未調用過AVAssetWriter的完成處理程序。
這是我的選擇器,將mp4文件URL列表,單個輸出文件URL和完成處理程序作為輸入。
- (void)resizeAndJoinVideosAtURLs:(NSArray *)videoURLs toOutputURL:(NSURL *)outputURL withHandler:(void(^)(NSURL *fileURL))handler
{
/*
First step: create the writer and writer input
*/
NSError *error = nil;
self.videoAssetWriter = [[AVAssetWriter alloc] initWithURL:outputURL fileType:AVFileTypeMPEG4 error:&error];
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecH264, AVVideoCodecKey,[NSNumber numberWithInt:640], AVVideoWidthKey,[NSNumber numberWithInt:480], AVVideoHeightKey,nil];
AVAssetWriterInput* videoWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];
videoWriterInput.expectsMediaDataInRealTime = NO;
if([self.videoAssetWriter canAddInput:videoWriterInput])
{
[self.videoAssetWriter addInput:videoWriterInput];
[self.videoAssetWriter startWriting];
[self.videoAssetWriter startSessionAtSourceTime:kCMTimeZero];
/*
Second step: for each video URL given create a reader and an reader input
*/
for(NSURL *videoURL in videoURLs)
{
NSLog(@"Processing file: %@",videoURL);
AVAsset *videoAsset = [[AVURLAsset alloc] initWithURL:videoURL options:nil];
AVAssetReader *videoAssetReader = [[AVAssetReader alloc] initWithAsset:videoAsset error:&error];
AVAssetTrack *videoAssetTrack = [videoAsset tracksWithMediaType:AVMediaTypeVideo].firstObject;
NSDictionary *videoOptions = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
AVAssetReaderTrackOutput *videoAssetTrackOutput = [[AVAssetReaderTrackOutput alloc] initWithTrack:videoAssetTrack outputSettings:videoOptions];
videoAssetTrackOutput.alwaysCopiesSampleData = NO;
if([videoAssetReader canAddOutput:videoAssetTrackOutput])
{
[videoAssetReader addOutput:videoAssetTrackOutput];
[videoAssetReader startReading];
/*
Step three: copy the buffers from the reader to the writer
*/
while ([videoAssetReader status] == AVAssetReaderStatusReading)
{
if(![videoWriterInput isReadyForMoreMediaData]) continue;
CMSampleBufferRef buffer = [videoAssetTrackOutput copyNextSampleBuffer];
if(buffer)
{
[videoWriterInput appendSampleBuffer:buffer];
CFRelease(buffer);
}
}
} else NSLog(@"ERROR: %@",error);
}
[videoWriterInput markAsFinished];
} else NSLog(@"ERROR: %@",error);
__weak ClipBuilder *weakself = self;
[self.videoAssetWriter finishWritingWithCompletionHandler:^{
handler(outputURL);
weakself.videoAssetWriter = nil;
}];
}
我的輸出文件存在,而AVAssetWriter存在,因為它是一個屬性,但仍未調用完成處理程序。 有什么可以解釋的?
謝謝你的幫助。
有什么可以解釋的?
這是我最終通過結合AVAssetReader / AVAssetWriter結合使用不同分辨率的mp4文件而實現的解決方案。
- (void)reencodeComposition:(AVComposition *)composition toMP4File:(NSURL *)mp4FileURL withCompletionHandler:(void (^)(void))handler
{
self.status = EncoderStatusEncoding;
/*
Create the asset writer to write the file on disk
*/
NSError *error = nil;
if([[NSFileManager defaultManager] fileExistsAtPath:mp4FileURL.path isDirectory:nil])
{
if(![[NSFileManager defaultManager] removeItemAtPath:mp4FileURL.path error:&error])
{
[self failWithError:error withCompletionHandler:handler];
return;
}
}
self.assetWriter = [[AVAssetWriter alloc] initWithURL:mp4FileURL fileType:AVFileTypeMPEG4 error:&error];
if(self.assetWriter)
{
/*
Get the audio and video track of the composition
*/
AVAssetTrack *videoAssetTrack = [composition tracksWithMediaType:AVMediaTypeVideo].firstObject;
AVAssetTrack *audioAssetTrack = [composition tracksWithMediaType:AVMediaTypeAudio].firstObject;
NSDictionary *videoSettings = @{AVVideoCodecKey:AVVideoCodecH264, AVVideoWidthKey:@(self.imageWidth), AVVideoHeightKey:@(self.imageHeight)};
/*
Add an input to be able to write the video in the file
*/
AVAssetWriterInput* videoWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];
videoWriterInput.expectsMediaDataInRealTime = YES;
if([self.assetWriter canAddInput:videoWriterInput])
{
[self.assetWriter addInput:videoWriterInput];
/*
Add an input to be able to write the audio in the file
*/
// Use this only if you know the format
// CMFormatDescriptionRef audio_fmt_desc_ = nil;
//
// AudioStreamBasicDescription audioFormat;
// bzero(&audioFormat, sizeof(audioFormat));
// audioFormat.mSampleRate = 44100;
// audioFormat.mFormatID = kAudioFormatMPEG4AAC;
// audioFormat.mFramesPerPacket = 1024;
// audioFormat.mChannelsPerFrame = 2;
// int bytes_per_sample = sizeof(float);
// audioFormat.mFormatFlags = kAudioFormatFlagIsFloat | kAudioFormatFlagIsPacked;
//
// audioFormat.mBitsPerChannel = bytes_per_sample * 8;
// audioFormat.mBytesPerPacket = bytes_per_sample * 2;
// audioFormat.mBytesPerFrame = bytes_per_sample * 2;
//
// CMAudioFormatDescriptionCreate(kCFAllocatorDefault,&audioFormat,0,NULL,0,NULL,NULL,&audio_fmt_desc_);
//
// AVAssetWriterInput* audioWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:nil sourceFormatHint:audio_fmt_desc_];
//
// AVAssetWriterInput* audioWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:nil sourceFormatHint:((__bridge CMAudioFormatDescriptionRef)audioAssetTrack.formatDescriptions.firstObject)];
audioWriterInput.expectsMediaDataInRealTime = YES;
if([self.assetWriter canAddInput:audioWriterInput])
{
[self.assetWriter addInput:audioWriterInput];
[self.assetWriter startWriting];
[self.assetWriter startSessionAtSourceTime:kCMTimeZero];
/*
Create the asset reader to read the mp4 files on the disk
*/
AVAssetReader *assetReader = [[AVAssetReader alloc] initWithAsset:composition error:&error];
NSDictionary *videoOptions = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
/*
Add an output to be able to retrieve the video in the files
*/
AVAssetReaderTrackOutput *videoAssetTrackOutput = [[AVAssetReaderTrackOutput alloc] initWithTrack:videoAssetTrack outputSettings:videoOptions];
videoAssetTrackOutput.alwaysCopiesSampleData = NO;
if([assetReader canAddOutput:videoAssetTrackOutput])
{
[assetReader addOutput:videoAssetTrackOutput];
/*
Add an output to be able to retrieve the video in the files
*/
AVAssetReaderTrackOutput *audioAssetTrackOutput = [[AVAssetReaderTrackOutput alloc] initWithTrack:audioAssetTrack outputSettings:nil];
videoAssetTrackOutput.alwaysCopiesSampleData = NO;
if([assetReader canAddOutput:audioAssetTrackOutput])
{
[assetReader addOutput:audioAssetTrackOutput];
[assetReader startReading];
/*
Read the mp4 files until the end and copy them in the output file
*/
dispatch_group_t encodingGroup = dispatch_group_create();
dispatch_group_enter(encodingGroup);
[audioWriterInput requestMediaDataWhenReadyOnQueue:self.encodingQueue usingBlock:^{
while ([audioWriterInput isReadyForMoreMediaData])
{
CMSampleBufferRef nextSampleBuffer = [audioAssetTrackOutput copyNextSampleBuffer];
if (nextSampleBuffer)
{
[audioWriterInput appendSampleBuffer:nextSampleBuffer];
CFRelease(nextSampleBuffer);
}
else
{
[audioWriterInput markAsFinished];
dispatch_group_leave(encodingGroup);
break;
}
}
}];
dispatch_group_enter(encodingGroup);
[videoWriterInput requestMediaDataWhenReadyOnQueue:self.encodingQueue usingBlock:^{
while ([videoWriterInput isReadyForMoreMediaData])
{
CMSampleBufferRef nextSampleBuffer = [videoAssetTrackOutput copyNextSampleBuffer];
if (nextSampleBuffer)
{
[videoWriterInput appendSampleBuffer:nextSampleBuffer];
CFRelease(nextSampleBuffer);
}
else
{
[videoWriterInput markAsFinished];
dispatch_group_leave(encodingGroup);
break;
}
}
}];
dispatch_group_wait(encodingGroup, DISPATCH_TIME_FOREVER);
} else [self failWithError:error withCompletionHandler:handler];
} else [self failWithError:error withCompletionHandler:handler];
} else [self failWithError:error withCompletionHandler:handler];
} else [self failWithError:error withCompletionHandler:handler];
__weak Encoder *weakself = self;
[self.assetWriter finishWritingWithCompletionHandler:^{
self.status = EncoderStatusCompleted;
handler();
weakself.assetWriter = nil;
self.encodingQueue = nil;
}];
}
else [self failWithError:error withCompletionHandler:handler];
}
用
- (dispatch_queue_t)encodingQueue
{
if(!_encodingQueue)
{
_encodingQueue = dispatch_queue_create("com.myProject.encoding", NULL);
}
return _encodingQueue;
}
此實現適用於我的項目TS2MP4,但最終我將不需要它。
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