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我想改變的是我選擇使用 UIImagePickerController.mov視頻文件的容器，並通過與AVAssetExportSession和AVAssetExportPresetMediumQuality壓縮shouldOptimizeForNetworkUse = YES他們.mp4容器。如何以編程方式在iPhone/iPad應用程序上執行最快的mov轉換爲mp4？
我需要以編程方式/示例代碼在iPhone/iPad上的應用程序執行速度最快trans-wrap
我試圖AVAssetExportSession.outputFileType屬性設置爲AVFileTypeMPEG4，但它不支持，我得到了一個例外。
我試圖做此轉換通過指定fileType:AVFileTypeMPEG4使用AVAssetWriter，其實我.mp4輸出文件，但它不是wrap-trans，輸出文件是3倍比源大，而轉換過程需要128 sec視頻與60 sec時間。
我需要的解決方案，很快就會運行並保持文件大小
這是我用來.mov到.mp4轉換代碼：
我設置assetWriter期權setUpReaderAndWriterReturningError方法
#import "MCVideoConverter.h"
#import <AVFoundation/AVAsset.h>
#import <AVFoundation/AVAssetTrack.h>
#import <AVFoundation/AVAssetReader.h>
#import <AVFoundation/AVAssetReaderOutput.h>
#import <AVFoundation/AVAssetWriter.h>
#import <AVFoundation/AVAssetWriterInput.h>
#import <AVFoundation/AVMediaFormat.h>
#import <AVFoundation/AVAudioSettings.h>
#import <AVFoundation/AVVideoSettings.h>
#import <AVFoundation/AVAssetImageGenerator.h>
#import <AVFoundation/AVTime.h>
#import <CoreMedia/CMSampleBuffer.h>
@protocol RWSampleBufferChannelDelegate;
@interface RWSampleBufferChannel : NSObject
{
@private
AVAssetReaderOutput *assetReaderOutput;
AVAssetWriterInput *assetWriterInput;
dispatch_block_t completionHandler;
dispatch_queue_t serializationQueue;
BOOL finished; // only accessed on serialization queue
}
- (id)initWithAssetReaderOutput:(AVAssetReaderOutput *)assetReaderOutput assetWriterInput:(AVAssetWriterInput *)assetWriterInput;
- (void)startWithDelegate:(id <RWSampleBufferChannelDelegate>)delegate completionHandler:(dispatch_block_t)completionHandler; // delegate is retained until completion handler is called. Completion handler is guaranteed to be called exactly once, whether reading/writing finishes, fails, or is cancelled. Delegate may be nil.
- (void)cancel;
@property (nonatomic, readonly) NSString *mediaType;
@end
@protocol RWSampleBufferChannelDelegate <NSObject>
@required
- (void)sampleBufferChannel:(RWSampleBufferChannel *)sampleBufferChannel didReadSampleBuffer:(CMSampleBufferRef)sampleBuffer;
@end
@interface MCVideoConverter() <RWSampleBufferChannelDelegate>
// These three methods are always called on the serialization dispatch queue
- (BOOL)setUpReaderAndWriterReturningError:(NSError **)outError; // make sure "tracks" key of asset is loaded before calling this
- (BOOL)startReadingAndWritingReturningError:(NSError **)outError;
- (void)readingAndWritingDidFinishSuccessfully:(BOOL)success withError:(NSError *)error;
@end
@implementation MCVideoConverter
+ (NSArray *)readableTypes
{
return [AVURLAsset audiovisualTypes];;
}
+ (BOOL)canConcurrentlyReadDocumentsOfType:(NSString *)typeName
{
return YES;
}
- (id)init
{
self = [super init];
if (self)
{
NSString *serializationQueueDescription = [NSString stringWithFormat:@"%@ serialization queue", self];
serializationQueue = dispatch_queue_create([serializationQueueDescription UTF8String], NULL);
}
return self;
}
- (void)dealloc
{
[asset release];
[outputURL release];
[assetReader release];
[assetWriter release];
[audioSampleBufferChannel release];
[videoSampleBufferChannel release];
if (serializationQueue)
dispatch_release(serializationQueue);
[super dealloc];
}
@synthesize asset=asset;
@synthesize timeRange=timeRange;
@synthesize writingSamples=writingSamples;
@synthesize outputURL=outputURL;
@synthesize propgerssView;
- (void)convertVideo:(NSURL*) inputURL outputURL: (NSURL*) _outputURL progress:(UIProgressView*) _propgerssView
{
self.asset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
self.propgerssView = _propgerssView;
cancelled = NO;
[self performSelector:@selector(startProgressSheetWithURL:) withObject:_outputURL afterDelay:0.0]; // avoid starting a new sheet while in
}
- (void)startProgressSheetWithURL:(NSURL *)localOutputURL
{
[self setOutputURL:localOutputURL];
[self setWritingSamples:YES];
AVAsset *localAsset = [self asset];
[localAsset loadValuesAsynchronouslyForKeys:[NSArray arrayWithObjects:@"tracks", @"duration", nil] completionHandler:^
{
// Dispatch the setup work to the serialization queue, to ensure this work is serialized with potential cancellation
dispatch_async(serializationQueue, ^{
// Since we are doing these things asynchronously, the user may have already cancelled on the main thread. In that case, simply return from this block
if (cancelled)
return;
BOOL success = YES;
NSError *localError = nil;
success = ([localAsset statusOfValueForKey:@"tracks" error:&localError] == AVKeyValueStatusLoaded);
if (success)
success = ([localAsset statusOfValueForKey:@"duration" error:&localError] == AVKeyValueStatusLoaded);
if (success)
{
[self setTimeRange:CMTimeRangeMake(kCMTimeZero, [localAsset duration])];
// AVAssetWriter does not overwrite files for us, so remove the destination file if it already exists
NSFileManager *fm = [NSFileManager defaultManager];
NSString *localOutputPath = [localOutputURL path];
if ([fm fileExistsAtPath:localOutputPath])
success = [fm removeItemAtPath:localOutputPath error:&localError];
}
// Set up the AVAssetReader and AVAssetWriter, then begin writing samples or flag an error
if (success)
success = [self setUpReaderAndWriterReturningError:&localError];
if (success)
success = [self startReadingAndWritingReturningError:&localError];
if (!success)
[self readingAndWritingDidFinishSuccessfully:success withError:localError];
});
}];
}
- (BOOL)setUpReaderAndWriterReturningError:(NSError **)outError
{
BOOL success = YES;
NSError *localError = nil;
AVAsset *localAsset = [self asset];
NSURL *localOutputURL = [self outputURL];
// Create asset reader and asset writer
assetReader = [[AVAssetReader alloc] initWithAsset:asset error:&localError];
success = (assetReader != nil);
if (success)
{
//changed assetWriter = [[AVAssetWriter alloc] initWithURL:localOutputURL fileType:AVFileTypeQuickTimeMovie error:&localError];
assetWriter = [[AVAssetWriter alloc] initWithURL:localOutputURL fileType:AVFileTypeMPEG4 error:&localError];
success = (assetWriter != nil);
}
// Create asset reader outputs and asset writer inputs for the first audio track and first video track of the asset
if (success)
{
AVAssetTrack *audioTrack = nil, *videoTrack = nil;
// Grab first audio track and first video track, if the asset has them
NSArray *audioTracks = [localAsset tracksWithMediaType:AVMediaTypeAudio];
if ([audioTracks count] > 0)
audioTrack = [audioTracks objectAtIndex:0];
NSArray *videoTracks = [localAsset tracksWithMediaType:AVMediaTypeVideo];
if ([videoTracks count] > 0)
videoTrack = [videoTracks objectAtIndex:0];
if (audioTrack)
{
// Decompress to Linear PCM with the asset reader
NSDictionary *decompressionAudioSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithUnsignedInt:kAudioFormatLinearPCM], AVFormatIDKey,
nil];
AVAssetReaderOutput *output = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:audioTrack outputSettings:decompressionAudioSettings];
[assetReader addOutput:output];
AudioChannelLayout stereoChannelLayout = {
.mChannelLayoutTag = kAudioChannelLayoutTag_Stereo,
.mChannelBitmap = 0,
.mNumberChannelDescriptions = 0
};
NSData *channelLayoutAsData = [NSData dataWithBytes:&stereoChannelLayout length:offsetof(AudioChannelLayout, mChannelDescriptions)];
// Compress to 128kbps AAC with the asset writer
NSDictionary *compressionAudioSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithUnsignedInt:kAudioFormatMPEG4AAC], AVFormatIDKey,
[NSNumber numberWithInteger:128000], AVEncoderBitRateKey,
[NSNumber numberWithInteger:44100], AVSampleRateKey,
channelLayoutAsData, AVChannelLayoutKey,
[NSNumber numberWithUnsignedInteger:2], AVNumberOfChannelsKey,
nil];
AVAssetWriterInput *input = [AVAssetWriterInput assetWriterInputWithMediaType:[audioTrack mediaType] outputSettings:compressionAudioSettings];
[assetWriter addInput:input];
// Create and save an instance of RWSampleBufferChannel, which will coordinate the work of reading and writing sample buffers
audioSampleBufferChannel = [[RWSampleBufferChannel alloc] initWithAssetReaderOutput:output assetWriterInput:input];
}
if (videoTrack)
{
// Decompress to ARGB with the asset reader
NSDictionary *decompressionVideoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithUnsignedInt:kCVPixelFormatType_32ARGB], (id)kCVPixelBufferPixelFormatTypeKey,
[NSDictionary dictionary], (id)kCVPixelBufferIOSurfacePropertiesKey,
nil];
AVAssetReaderOutput *output = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:videoTrack outputSettings:decompressionVideoSettings];
[assetReader addOutput:output];
// Get the format description of the track, to fill in attributes of the video stream that we don't want to change
CMFormatDescriptionRef formatDescription = NULL;
NSArray *formatDescriptions = [videoTrack formatDescriptions];
if ([formatDescriptions count] > 0)
formatDescription = (CMFormatDescriptionRef)[formatDescriptions objectAtIndex:0];
// Grab track dimensions from format description
CGSize trackDimensions = {
.width = 0.0,
.height = 0.0,
};
if (formatDescription)
trackDimensions = CMVideoFormatDescriptionGetPresentationDimensions(formatDescription, false, false);
else
trackDimensions = [videoTrack naturalSize];
// Grab clean aperture, pixel aspect ratio from format description
NSMutableDictionary *compressionSettings = nil;
// [NSMutableDictionary dictionaryWithObjectsAndKeys:
// AVVideoProfileLevelH264Baseline30, AVVideoProfileLevelKey,
// [NSNumber numberWithInt:960000], AVVideoAverageBitRateKey,
// [NSNumber numberWithInt:1],AVVideoMaxKeyFrameIntervalKey,
// nil ];
//NSDictionary *videoSettings = nil;
if (formatDescription)
{
NSDictionary *cleanAperture = nil;
NSDictionary *pixelAspectRatio = nil;
CFDictionaryRef cleanApertureFromCMFormatDescription = CMFormatDescriptionGetExtension(formatDescription, kCMFormatDescriptionExtension_CleanAperture);
if (cleanApertureFromCMFormatDescription)
{
cleanAperture = [NSDictionary dictionaryWithObjectsAndKeys:
CFDictionaryGetValue(cleanApertureFromCMFormatDescription, kCMFormatDescriptionKey_CleanApertureWidth), AVVideoCleanApertureWidthKey,
CFDictionaryGetValue(cleanApertureFromCMFormatDescription, kCMFormatDescriptionKey_CleanApertureHeight), AVVideoCleanApertureHeightKey,
CFDictionaryGetValue(cleanApertureFromCMFormatDescription, kCMFormatDescriptionKey_CleanApertureHorizontalOffset), AVVideoCleanApertureHorizontalOffsetKey,
CFDictionaryGetValue(cleanApertureFromCMFormatDescription, kCMFormatDescriptionKey_CleanApertureVerticalOffset), AVVideoCleanApertureVerticalOffsetKey,
nil];
}
CFDictionaryRef pixelAspectRatioFromCMFormatDescription = CMFormatDescriptionGetExtension(formatDescription, kCMFormatDescriptionExtension_PixelAspectRatio);
if (pixelAspectRatioFromCMFormatDescription)
{
pixelAspectRatio = [NSDictionary dictionaryWithObjectsAndKeys:
CFDictionaryGetValue(pixelAspectRatioFromCMFormatDescription, kCMFormatDescriptionKey_PixelAspectRatioHorizontalSpacing), AVVideoPixelAspectRatioHorizontalSpacingKey,
CFDictionaryGetValue(pixelAspectRatioFromCMFormatDescription, kCMFormatDescriptionKey_PixelAspectRatioVerticalSpacing), AVVideoPixelAspectRatioVerticalSpacingKey,
nil];
}
if (cleanAperture || pixelAspectRatio)
{
if (cleanAperture)
[compressionSettings setObject:cleanAperture forKey:AVVideoCleanApertureKey];
if (pixelAspectRatio)
[compressionSettings setObject:pixelAspectRatio forKey:AVVideoPixelAspectRatioKey];
}
}
// Compress to H.264 with the asset writer
NSMutableDictionary *videoSettings = [NSMutableDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithDouble:trackDimensions.width], AVVideoWidthKey,
[NSNumber numberWithDouble:trackDimensions.height], AVVideoHeightKey,
nil];
if (compressionSettings)
[videoSettings setObject:compressionSettings forKey:AVVideoCompressionPropertiesKey];
AVAssetWriterInput *input = [AVAssetWriterInput assetWriterInputWithMediaType:[videoTrack mediaType] outputSettings:videoSettings];
[assetWriter addInput:input];
// Create and save an instance of RWSampleBufferChannel, which will coordinate the work of reading and writing sample buffers
videoSampleBufferChannel = [[RWSampleBufferChannel alloc] initWithAssetReaderOutput:output assetWriterInput:input];
}
}
if (outError)
*outError = localError;
return success;
}
- (BOOL)startReadingAndWritingReturningError:(NSError **)outError
{
BOOL success = YES;
NSError *localError = nil;
// Instruct the asset reader and asset writer to get ready to do work
success = [assetReader startReading];
if (!success)
localError = [assetReader error];
if (success)
{
success = [assetWriter startWriting];
if (!success)
localError = [assetWriter error];
}
if (success)
{
dispatch_group_t dispatchGroup = dispatch_group_create();
// Start a sample-writing session
[assetWriter startSessionAtSourceTime:[self timeRange].start];
// Start reading and writing samples
if (audioSampleBufferChannel)
{
// Only set audio delegate for audio-only assets, else let the video channel drive progress
id <RWSampleBufferChannelDelegate> delegate = nil;
if (!videoSampleBufferChannel)
delegate = self;
dispatch_group_enter(dispatchGroup);
[audioSampleBufferChannel startWithDelegate:delegate completionHandler:^{
dispatch_group_leave(dispatchGroup);
}];
}
if (videoSampleBufferChannel)
{
dispatch_group_enter(dispatchGroup);
[videoSampleBufferChannel startWithDelegate:self completionHandler:^{
dispatch_group_leave(dispatchGroup);
}];
}
// Set up a callback for when the sample writing is finished
dispatch_group_notify(dispatchGroup, serializationQueue, ^{
BOOL finalSuccess = YES;
NSError *finalError = nil;
if (cancelled)
{
[assetReader cancelReading];
[assetWriter cancelWriting];
}
else
{
if ([assetReader status] == AVAssetReaderStatusFailed)
{
finalSuccess = NO;
finalError = [assetReader error];
}
if (finalSuccess)
{
finalSuccess = [assetWriter finishWriting];
if (!finalSuccess)
finalError = [assetWriter error];
}
}
[self readingAndWritingDidFinishSuccessfully:finalSuccess withError:finalError];
});
dispatch_release(dispatchGroup);
}
if (outError)
*outError = localError;
return success;
}
- (void)cancel
{
self.propgerssView = nil;
// Dispatch cancellation tasks to the serialization queue to avoid races with setup and teardown
dispatch_async(serializationQueue, ^{
[audioSampleBufferChannel cancel];
[videoSampleBufferChannel cancel];
cancelled = YES;
});
}
- (void)readingAndWritingDidFinishSuccessfully:(BOOL)success withError:(NSError *)error
{
NSLog(@"%s[%d] - success = %d error = %@", __FUNCTION__, __LINE__, success, error);
if (!success)
{
[assetReader cancelReading];
[assetWriter cancelWriting];
}
// Tear down ivars
[assetReader release];
assetReader = nil;
[assetWriter release];
assetWriter = nil;
[audioSampleBufferChannel release];
audioSampleBufferChannel = nil;
[videoSampleBufferChannel release];
videoSampleBufferChannel = nil;
cancelled = NO;
// Dispatch UI-related tasks to the main queue
dispatch_async(dispatch_get_main_queue(), ^{
if (!success)
{
}
[self setWritingSamples:NO];
});
}
static double progressOfSampleBufferInTimeRange(CMSampleBufferRef sampleBuffer, CMTimeRange timeRange)
{
CMTime progressTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
progressTime = CMTimeSubtract(progressTime, timeRange.start);
CMTime sampleDuration = CMSampleBufferGetDuration(sampleBuffer);
if (CMTIME_IS_NUMERIC(sampleDuration))
progressTime= CMTimeAdd(progressTime, sampleDuration);
return CMTimeGetSeconds(progressTime)/CMTimeGetSeconds(timeRange.duration);
}
static void removeARGBColorComponentOfPixelBuffer(CVPixelBufferRef pixelBuffer, size_t componentIndex)
{
CVPixelBufferLockBaseAddress(pixelBuffer, 0);
size_t bufferHeight = CVPixelBufferGetHeight(pixelBuffer);
size_t bufferWidth = CVPixelBufferGetWidth(pixelBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(pixelBuffer);
static const size_t bytesPerPixel = 4; // constant for ARGB pixel format
unsigned char *base = (unsigned char *)CVPixelBufferGetBaseAddress(pixelBuffer);
for (size_t row = 0; row < bufferHeight; ++row)
{
for (size_t column = 0; column < bufferWidth; ++column)
{
unsigned char *pixel = base + (row * bytesPerRow) + (column * bytesPerPixel);
pixel[componentIndex] = 0;
}
}
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
}
+ (size_t)componentIndexFromFilterTag:(NSInteger)filterTag
{
return (size_t)filterTag; // we set up the tags in the popup button to correspond directly with the index they modify
}
- (void)sampleBufferChannel:(RWSampleBufferChannel *)sampleBufferChannel didReadSampleBuffer:(CMSampleBufferRef)sampleBuffer
{
CVPixelBufferRef pixelBuffer = NULL;
// Calculate progress (scale of 0.0 to 1.0)
double progress = progressOfSampleBufferInTimeRange(sampleBuffer, [self timeRange]);
NSLog(@"%s[%d] - progress = %f", __FUNCTION__, __LINE__, progress);
// Grab the pixel buffer from the sample buffer, if possible
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
if (imageBuffer && (CFGetTypeID(imageBuffer) == CVPixelBufferGetTypeID()))
{
pixelBuffer = (CVPixelBufferRef)imageBuffer;
if (filterTag >= 0) // -1 means "no filtering, please"
removeARGBColorComponentOfPixelBuffer(pixelBuffer, [[self class] componentIndexFromFilterTag:filterTag]);
}
}
@end
@interface RWSampleBufferChannel()
- (void)callCompletionHandlerIfNecessary; // always called on the serialization queue
@end
@implementation RWSampleBufferChannel
- (id)initWithAssetReaderOutput:(AVAssetReaderOutput *)localAssetReaderOutput assetWriterInput:(AVAssetWriterInput *)localAssetWriterInput
{
self = [super init];
if (self)
{
assetReaderOutput = [localAssetReaderOutput retain];
assetWriterInput = [localAssetWriterInput retain];
finished = NO;
NSString *serializationQueueDescription = [NSString stringWithFormat:@"%@ serialization queue", self];
serializationQueue = dispatch_queue_create([serializationQueueDescription UTF8String], NULL);
}
return self;
}
- (void)dealloc
{
[assetReaderOutput release];
[assetWriterInput release];
if (serializationQueue)
dispatch_release(serializationQueue);
[completionHandler release];
[super dealloc];
}
- (NSString *)mediaType
{
return [assetReaderOutput mediaType];
}
- (void)startWithDelegate:(id <RWSampleBufferChannelDelegate>)delegate completionHandler:(dispatch_block_t)localCompletionHandler
{
completionHandler = [localCompletionHandler copy]; // released in -callCompletionHandlerIfNecessary
[assetWriterInput requestMediaDataWhenReadyOnQueue:serializationQueue usingBlock:^{
if (finished)
return;
BOOL completedOrFailed = NO;
// Read samples in a loop as long as the asset writer input is ready
while ([assetWriterInput isReadyForMoreMediaData] && !completedOrFailed)
{
CMSampleBufferRef sampleBuffer = [assetReaderOutput copyNextSampleBuffer];
if (sampleBuffer != NULL)
{
if ([delegate respondsToSelector:@selector(sampleBufferChannel:didReadSampleBuffer:)])
[delegate sampleBufferChannel:self didReadSampleBuffer:sampleBuffer];
BOOL success = [assetWriterInput appendSampleBuffer:sampleBuffer];
CFRelease(sampleBuffer);
sampleBuffer = NULL;
completedOrFailed = !success;
}
else
{
completedOrFailed = YES;
}
}
if (completedOrFailed)
[self callCompletionHandlerIfNecessary];
}];
}
- (void)cancel
{
dispatch_async(serializationQueue, ^{
[self callCompletionHandlerIfNecessary];
});
}
- (void)callCompletionHandlerIfNecessary
{
// Set state to mark that we no longer need to call the completion handler, grab the completion handler, and clear out the ivar
BOOL oldFinished = finished;
finished = YES;
if (oldFinished == NO)
{
[assetWriterInput markAsFinished]; // let the asset writer know that we will not be appending any more samples to this input
dispatch_block_t localCompletionHandler = [completionHandler retain];
[completionHandler release];
completionHandler = nil;
if (localCompletionHandler)
{
localCompletionHandler();
[localCompletionHandler release];
}
}
}
@end
我試過這個，AVFoundation抱怨說我的親水res視頻不兼容mp4。你知道一個不同的方式來做到這一點嗎？ – Eric 2015-01-26 02:53:28