简介:
使用AVAssetWriter AVAssetReader 等相关类,实现了AVAssetExportSession相关功能,最初的目的是为定位AVAssetExportSession导出过程出现卡住,不回调block的bug.
说明:
1.本类编写借鉴了SDAVAssetExportSession
2.本类目前不支持实时进度功能
3.copyNextSampleBuffer 函数不返回,是导致export过程卡住的原因, 需要修改videoComposition的CMTimeScale来避免.尽量不要出现让reader读取不是整数帧时间(CMTime)的情况发生.
例如:CMTime start = CMTimeMakeWithSeconds(CMTimeGetSeconds(_clipRange.start), 30);
简易流程图
image.png
//
// AHAVAssetExportSession.h
// demo
//
// Created by 李田迎 on 2019/7/18.
// Copyright © 2019. All rights reserved.
// 自定义实现 多媒体数据导出到本地功能
#import
#import
NS_ASSUME_NONNULL_BEGIN
@interfaceAHAVAssetExportSession :NSObject
//入参
@property(nonatomic,copy)NSString*outputFileType; //!< 导出文件类型
@property(nonatomic,copy)NSURL*outputURL; //!< 导出资源路径
@property(nonatomic,copy)NSDictionary*videoSettings; //!< 视频配置参数 有默认参数
@property(nonatomic,copy)NSDictionary*audioSettings; //!< 音频配置参数 有默认参数
@property(nonatomic,copy)NSArray*metadata; //!< 多媒体数据中的元数据
@property(nonatomic,copy)AVVideoComposition*videoComposition;//!< 视频轨道组合对象
@property(nonatomic,copy)AVAudioMix*audioMix; //!< 音轨混合对象
@property(nonatomic,assign)CGSizetargetSize; //!< 导出视频size
@property(nonatomic,assign)BOOLshouldOptimizeForNetworkUse;//!< 是否使用网络优化
//出参
@property (nonatomic, assign, readonly) AVAssetExportSessionStatusstatus; //!< 导出状态
@property(nonatomic,strong,readonly)NSError*error; //!< 导出错误信息
@property(nonatomic,assign,readonly)CGFloatprogress; //!< 导出进度 0-1
/**
初始化方法
@param asset 多媒体资源
@return 本类实例对象
*/
- (id)initWithAsset:(AVAsset*)asset;
/**
导出函数
@param handler 导出完成回调block
*/
- (void)exportAsynchronouslyWithCompletionHandler:(void(^)(void))handler;
/**
取消中断导出操作
*/
- (void)cancelExport;
@end
NS_ASSUME_NONNULL_END
//
// AHAVAssetExportSession.m
// demo
//
// Created by 李田迎 on 2019/7/18.
// Copyright © 2019. All rights reserved.
//
#import "AHAVAssetExportSession.h"
#import "AHVideoRecordDef.h"
#import "AHVideoRecordCustomConfig.h"
@interface AHAVAssetExportSession()
@property(nonatomic,strong)AVAssetReader*assetReader; //!< 资源读取对象
//!< 视频组合读取输出对象
@property (nonatomic, strong) AVAssetReaderVideoCompositionOutput *videoOutput;
//!< 音频混合读取输出对象
@property (nonatomic, strong) AVAssetReaderAudioMixOutput *audioOutput;
@property(nonatomic,strong)AVAssetWriter*assetWriter; //!< 多媒体文件写入
@property (nonatomic, strong) AVAssetWriterInput*videoInput; //!< 视频写入 append
@property (nonatomic, strong) AVAssetWriterInput*audioInput; //!< 音频写入对象
@property (nonatomic, strong) AVAssetWriterInputPixelBufferAdaptor *videoPixelBufferAdaptor;
@property(nonatomic,strong)dispatch_queue_tinputQueue; //!< 多媒体数据写入队列
@property(nonatomic,strong) AVAsset *asset; //!< 素材资源对象
@property(nonatomic,strong)void(^completionHandler)(void); //!< 回调block
@property (nonatomic, assign, readwrite) CGFloat progress; //!< 处理进度
@end
@implementationAHAVAssetExportSession {
NSError *_error;
}
#pragma mark LifeCycle Method
- (id)initWithAsset:(AVAsset *)asset {
if(self= [superinit]) {
self.asset = asset;
_targetSize = CGSizeMake(KVideoPixelsWidth, kVideoPixelsHeight);
}
return self;
}
- (void)dealloc {
}
#pragma mark Public Method
- (void)exportAsynchronouslyWithCompletionHandler:(void(^)(void))handler {
[selfcancelExport];
self.completionHandler = handler;
//1.为添加assetReader添加视频音频读写对象
if([self.assetReader canAddOutput:self.videoOutput]) {
[self.assetReader addOutput:self.videoOutput];
}
if([self.assetReader canAddOutput:self.audioOutput]) {
[self.assetReader addOutput:self.audioOutput];
}
//2.为asserWriter添加writerInput
if([self.assetWriter canAddInput:self.videoInput]) {
[self.assetWriter addInput:self.videoInput];
}
if([self.assetWriter canAddInput:self.audioInput]) {
[self.assetWriter addInput:self.audioInput];
}
//3.开始读写操作
[self.assetWriter startWriting];
[self.assetReader startReading];
[self.assetWriter startSessionAtSourceTime:kCMTimeZero];
__blockBOOLvideoCompleted =NO;
__blockBOOLaudioCompleted =NO;
__weak typeof(self) wself = self;
//4.请求视频轨道写入数据
[self.videoInput requestMediaDataWhenReadyOnQueue:self.inputQueue usingBlock:^
{
if(![wself encodeReadySamplesFromOutput:wself.videoOutput toInput:wself.videoInput])
{
@synchronized(wself)
{
videoCompleted =YES;
if(audioCompleted)
{
[wselffinish];
}
}
}
}];
//5.请求音频轨道写入数据
[self.audioInput requestMediaDataWhenReadyOnQueue:self.inputQueue usingBlock:^ {
if (![wself encodeReadySamplesFromOutput:wself.audioOutput toInput:wself.audioInput]) {
@synchronized(wself) {
audioCompleted =YES;
if(videoCompleted) {
[wselffinish];
}
}
}
}];
}
- (void)cancelExport {
if (!_inputQueue) {
return;
}
dispatch_async(self.inputQueue, ^{
[self.assetWritercancelWriting];
[self.assetReadercancelReading];
[selfcomplete];
[selfreset];
});
}
#pragma mark Private Method
- (BOOL)encodeReadySamplesFromOutput:(AVAssetReaderOutput*)output toInput:(AVAssetWriterInput*)input {
while (input.isReadyForMoreMediaData) {
CMSampleBufferRef sampleBuffer = [output copyNextSampleBuffer];
if(sampleBuffer) {
BOOLhandled =NO;
BOOLerror =NO;
if (self.assetReader.status != AVAssetReaderStatusReading || self.assetWriter.status != AVAssetWriterStatusWriting) {
handled =YES;
error =YES;
}
if(!handled && ![inputappendSampleBuffer:sampleBuffer]) {
error =YES;
}
CFRelease(sampleBuffer);
if(error) {
returnNO;
}
}else{
[inputmarkAsFinished];
returnNO;
}
}
return YES;
}
- (void)reset {
_error=nil;
self.progress=0;
if (_assetReader) {
_assetReader=nil;
}
if(_videoOutput) {
_videoOutput =nil;
}
if(_audioOutput) {
_audioOutput =nil;
}
if(_assetWriter) {
_assetWriter =nil;
}
if(_videoInput) {
_videoInput =nil;
}
if(_videoPixelBufferAdaptor) {
_videoPixelBufferAdaptor =nil;
}
if(_audioOutput) {
_audioOutput =nil;
}
if(_inputQueue) {
_inputQueue =nil;
}
self.completionHandler =nil;
}
- (void)finish {
// Synchronized block to ensure we never cancel the writer before calling finishWritingWithCompletionHandler
if(self.assetReader.status == AVAssetReaderStatusCancelled ||self.assetWriter.status == AVAssetWriterStatusCancelled) {
return;
}
if(self.assetWriter.status == AVAssetWriterStatusFailed) {
[selfcomplete];
}elseif(self.assetReader.status == AVAssetReaderStatusFailed) {
[self.assetWriter cancelWriting];
[selfcomplete];
}else{
[self.assetWriter finishWritingWithCompletionHandler:^ {
[selfcomplete];
}];
}
}
- (void)complete {
if(self.assetWriter.status == AVAssetWriterStatusFailed ||self.assetWriter.status == AVAssetWriterStatusCancelled) {
[NSFileManager.defaultManager removeItemAtURL:self.outputURL error:nil];
}
if(self.completionHandler) {
self.completionHandler();
self.completionHandler =nil;
}
}
- (NSError *)error {
if(_error) {
return_error;
}else{
returnself.assetWriter.error ? :self.assetReader.error;
}
}
- (AVMutableVideoComposition *)buildDefaultVideoComposition {
AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];
AVAssetTrack *videoTrack = [[self.asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
// get the frame rate from videoSettings, if not set then try to get it from the video track,
// if not set (mainly when asset is AVComposition) then use the default frame rate of 30
floattrackFrameRate =0;
if(self.videoSettings) {
NSDictionary *videoCompressionProperties = [self.videoSettings objectForKey:AVVideoCompressionPropertiesKey];
if(videoCompressionProperties) {
NSNumber *frameRate = [videoCompressionProperties objectForKey:AVVideoAverageNonDroppableFrameRateKey];
if(frameRate) {
trackFrameRate = frameRate.floatValue;
}
}
}else{
trackFrameRate = [videoTrack nominalFrameRate];
}
if(trackFrameRate ==0) {
trackFrameRate = kDefaultVideoFrameRate;
}
videoComposition.frameDuration = CMTimeMake(1, trackFrameRate);
CGSize targetSize = CGSizeMake([self.videoSettings[AVVideoWidthKey] floatValue], [self.videoSettings[AVVideoHeightKey] floatValue]);
CGSize naturalSize = [videoTrack naturalSize];
CGAffineTransform transform = videoTrack.preferredTransform;
// Workaround radar 31928389, see https://github.com/rs/SDAVAssetExportSession/pull/70 for more info
if(transform.ty == -560) {
transform.ty =0;
}
if(transform.tx == -560) {
transform.tx =0;
}
CGFloat videoAngleInDegree = atan2(transform.b, transform.a) *180/ M_PI;
if(videoAngleInDegree ==90|| videoAngleInDegree == -90) {
CGFloat width = naturalSize.width;
naturalSize.width = naturalSize.height;
naturalSize.height = width;
}
videoComposition.renderSize = naturalSize;
// center inside
{
floatratio;
floatxratio = targetSize.width / naturalSize.width;
floatyratio = targetSize.height / naturalSize.height;
ratio = MIN(xratio, yratio);
floatpostWidth = naturalSize.width * ratio;
floatpostHeight = naturalSize.height * ratio;
floattransx = (targetSize.width - postWidth) /2;
floattransy = (targetSize.height - postHeight) /2;
CGAffineTransform matrix = CGAffineTransformMakeTranslation(transx / xratio, transy / yratio);
matrix = CGAffineTransformScale(matrix, ratio / xratio, ratio / yratio);
transform = CGAffineTransformConcat(transform, matrix);
}
// Make a "pass through video track" video composition.
AVMutableVideoCompositionInstruction *passThroughInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
passThroughInstruction.timeRange = CMTimeRangeMake(kCMTimeZero,self.asset.duration);
AVMutableVideoCompositionLayerInstruction *passThroughLayer = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
[passThroughLayer setTransform:transform atTime:kCMTimeZero];
passThroughInstruction.layerInstructions =@[passThroughLayer];
videoComposition.instructions =@[passThroughInstruction];
returnvideoComposition;
}
#pragma mark Get Method
- (AVAssetExportSessionStatus)status {
switch(self.assetWriter.status) {
default:
caseAVAssetWriterStatusUnknown:
returnAVAssetExportSessionStatusUnknown;
caseAVAssetWriterStatusWriting:
returnAVAssetExportSessionStatusExporting;
caseAVAssetWriterStatusFailed:
returnAVAssetExportSessionStatusFailed;
caseAVAssetWriterStatusCompleted:
returnAVAssetExportSessionStatusCompleted;
caseAVAssetWriterStatusCancelled:
returnAVAssetExportSessionStatusCancelled;
}
}
- (dispatch_queue_t)inputQueue {
if(!_inputQueue) {
_inputQueue = dispatch_queue_create("AHSVVideoEncoderInputQueue", DISPATCH_QUEUE_SERIAL);
}
return_inputQueue;
}
- (AVAssetReader *)assetReader {
if(!_assetReader) {
NSError *error;
_assetReader = [[AVAssetReader alloc] initWithAsset:self.asset error:&error];
if(error) {
NSLog(@"assetReader 创建失败!! %@", error);
}
}
return_assetReader;
}
- (AVAssetReaderVideoCompositionOutput *)videoOutput {
if(!_videoOutput) {
NSArray *videoTracks = [self.asset tracksWithMediaType:AVMediaTypeVideo];
_videoOutput = [[AVAssetReaderVideoCompositionOutput alloc] initWithVideoTracks:videoTracks videoSettings:nil];
_videoOutput.videoComposition =self.videoComposition;
}
return_videoOutput;
}
- (AVAssetReaderAudioMixOutput *)audioOutput {
if(!_audioOutput) {
NSArray *audioTracks = [self.asset tracksWithMediaType:AVMediaTypeAudio];
_audioOutput = [AVAssetReaderAudioMixOutput assetReaderAudioMixOutputWithAudioTracks:audioTracks audioSettings:nil];
_audioOutput.audioMix =self.audioMix;
}
return_audioOutput;
}
- (AVAssetWriterInputPixelBufferAdaptor *)videoPixelBufferAdaptor {
if(!_videoPixelBufferAdaptor) {
NSDictionary *pixelBufferAttributes =@{
(id)kCVPixelBufferPixelFormatTypeKey:@(kCVPixelFormatType_32BGRA),
(id)kCVPixelBufferWidthKey:@(self.videoOutput.videoComposition.renderSize.width),
(id)kCVPixelBufferHeightKey:@(self.videoOutput.videoComposition.renderSize.height),
@"IOSurfaceOpenGLESTextureCompatibility": @YES,
@"IOSurfaceOpenGLESFBOCompatibility": @YES,
};
_videoPixelBufferAdaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:self.videoInput sourcePixelBufferAttributes:pixelBufferAttributes];
}
return_videoPixelBufferAdaptor;
}
- (AVVideoComposition *)videoComposition {
if(!_videoComposition) {
_videoComposition = [selfbuildDefaultVideoComposition];
}
return_videoComposition;
}
- (AVAssetWriter *)assetWriter {
if(!_assetWriter) {
NSError *writerError;
_assetWriter = [AVAssetWriter assetWriterWithURL:self.outputURL fileType:self.outputFileType error:&writerError];
_assetWriter.shouldOptimizeForNetworkUse =self.shouldOptimizeForNetworkUse;
if(writerError) {
NSLog(@"assetWriterc 创建失败 %@", writerError);
}
}
return_assetWriter;
}
- (AVAssetWriterInput *)videoInput {
if(!_videoInput) {
_videoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:self.videoSettings];
_videoInput.expectsMediaDataInRealTime =NO;
}
return_videoInput;
}
- (AVAssetWriterInput *)audioInput {
if(!_audioInput) {
_audioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:self.audioSettings];
_audioInput.expectsMediaDataInRealTime =NO;
}
return_audioInput;
}
- (NSDictionary *)videoSettings {
if(!_videoSettings) {
_videoSettings =@{AVVideoCodecKey: AVVideoCodecH264,
AVVideoWidthKey:@(self.targetSize.width),
AVVideoHeightKey:@(self.targetSize.height),
AVVideoCompressionPropertiesKey:@{
AVVideoAverageBitRateKey:@(6000000),
AVVideoProfileLevelKey: AVVideoProfileLevelH264High40
},
};
}
return_videoSettings;
}
- (NSDictionary *)audioSettings {
if(!_audioSettings) {
_audioSettings =@{AVFormatIDKey:@(kAudioFormatMPEG4AAC),
AVNumberOfChannelsKey:@(2),
AVSampleRateKey:@(44100),
AVEncoderBitRateKey:@(128000),
};
}
return_audioSettings;
}
#pragma mark Set Method
@end
