首先了解下AVFoundation
AVFoundation框架是ios中很重要的框架，是蘋果 OS X 系統和 iOS系統中用于處理基于時間的媒體數據的高級框架，其設計過程高度依賴多線程機制。所有與視頻音頻相關的軟硬件控制都在這個框架里面。
AVFoundation是可以用它來播放和創建基于時間的視聽媒體的幾個框架之一，它提供了基于時間的視聽數據的詳細界別上的OC接口。可以用它來檢查、創建、編輯、重新編碼媒體文件。也可以從設備得到輸入流和實時捕捉回放過程中操控視頻，是用于處理基于時間的媒體數據的高級OC框架。充分利用了多核硬件的優勢并大量使用block和Grand Central Dispatch(GCD)機制將復雜的計算進程放在后臺線程運行。自動提供硬件加速操作，確保在大部分設備上應用程序能以最佳性能運行。
而AVAssetWriter和AVPlayer也是屬于AVFoundation框架內的
Github代碼地址
一、采集音視頻
/** 負責輸入和輸出設備之間的數據傳遞 */
@property (strong, nonatomic) AVCaptureSession *captureSession;
/** 視頻輸入 */
@property (nonatomic, strong) AVCaptureDeviceInput *videoInput;
/** 視頻輸出 */
@property (nonatomic, strong) AVCaptureVideoDataOutput *videoOutput;
/** 聲音輸出 */
@property (nonatomic, strong) AVCaptureAudioDataOutput *audioOutput;
/** 預覽圖層 */
@property (strong, nonatomic) AVCaptureVideoPreviewLayer *captureVideoPreviewLayer;
這里使用這些類來采集音視頻。
首先，初始化AVCaptureSession
- (AVCaptureSession *)captureSession
{
if (_captureSession == nil)
{
_captureSession = [[AVCaptureSession alloc] init];
if ([_captureSession canSetSessionPreset:AVCaptureSessionPresetHigh])
{
_captureSession.sessionPreset = AVCaptureSessionPresetHigh;
}
}
return _captureSession;
}
初始化視頻音頻輸入輸出
/**
* 設置視頻輸入
*/
- (void)setupVideo
{
AVCaptureDevice *captureDevice = [self getCameraDeviceWithPosition:AVCaptureDevicePositionBack];
if (!captureDevice)
{
NSLog(@"取得后置攝像頭時出現問題.");
return;
}
NSError *error = nil;
AVCaptureDeviceInput *videoInput = [[AVCaptureDeviceInput alloc] initWithDevice:captureDevice error:&error];
if (error)
{
NSLog(@"取得設備輸入videoInput對象時出錯，錯誤原因：%@", error);
return;
}
//3、將設備輸出添加到會話中
if ([self.captureSession canAddInput:videoInput])
{
[self.captureSession addInput:videoInput];
}
self.videoOutput = [[AVCaptureVideoDataOutput alloc] init];
self.videoOutput.alwaysDiscardsLateVideoFrames = NO; //立即丟棄舊幀，節省內存，默認YES
[self.videoOutput setVideoSettings:[NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarFullRange] forKey:(id)kCVPixelBufferPixelFormatTypeKey]];
[self.videoOutput setSampleBufferDelegate:self queue:self.videoQueue];
if ([self.captureSession canAddOutput:self.videoOutput])
{
[self.captureSession addOutput:self.videoOutput];
}
AVCaptureConnection *connection = [self.videoOutput connectionWithMediaType:AVMediaTypeVideo];
[connection setVideoOrientation:AVCaptureVideoOrientationPortrait];
self.videoInput = videoInput;
}
/**
* 設置音頻錄入
*/
- (void)setupAudio
{
NSError *error = nil;
AVCaptureDeviceInput *audioInput = [[AVCaptureDeviceInput alloc] initWithDevice:[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio] error:&error];
if (error)
{
NSLog(@"取得設備輸入audioInput對象時出錯，錯誤原因：%@", error);
return;
}
if ([self.captureSession canAddInput:audioInput])
{
[self.captureSession addInput:audioInput];
}
self.audioOutput = [[AVCaptureAudioDataOutput alloc] init];
[self.audioOutput setSampleBufferDelegate:self queue:self.videoQueue];
if([self.captureSession canAddOutput:self.audioOutput])
{
[self.captureSession addOutput:self.audioOutput];
}
}
設置預覽圖層
/**
* 設置預覽layer
*/
- (void)setupCaptureVideoPreviewLayer
{
_captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];
_captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspect; //填充模式
[_captureVideoPreviewLayer setFrame:self.superView.bounds];
[self.superView.layer addSublayer:_captureVideoPreviewLayer];
}
然后開始采集
采集的音視頻數據回調代理方法：
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
@autoreleasepool
{
//視頻
if (connection == [self.videoOutput connectionWithMediaType:AVMediaTypeVideo])
{
@synchronized(self)
{
if (self.captureBlock) {
self.captureBlock(sampleBuffer, AVMediaTypeVideo);
}
}
}
//音頻
if (connection == [self.audioOutput connectionWithMediaType:AVMediaTypeAudio])
{
@synchronized(self)
{
if (self.captureBlock) {
self.captureBlock(sampleBuffer, AVMediaTypeAudio);
}
}
}
}
}
這里將采集的數據傳遞出去，進行錄制處理
二、錄制音視頻
/** 寫入音視頻 */
@property (nonatomic, strong) AVAssetWriter *assetWriter;
/** 寫入視頻輸出 */
@property (nonatomic, strong) AVAssetWriterInput *assetWriterVideoInput;
/** 寫入音頻輸出 */
@property (nonatomic, strong) AVAssetWriterInput *assetWriterAudioInput;
這里使用AVAssetWriter來錄制音視頻
首先初始化AVAssetWriter
/**
* 設置寫入視頻屬性
*/
- (void)setUpWriter
{
if (self.videoURL == nil)
{
return;
}
self.assetWriter = [AVAssetWriter assetWriterWithURL:self.videoURL fileType:AVFileTypeMPEG4 error:nil];
//寫入視頻大小
NSInteger numPixels = kScreenWidth * kScreenHeight;
//每像素比特
CGFloat bitsPerPixel = 12.0;
NSInteger bitsPerSecond = numPixels * bitsPerPixel;
// 碼率和幀率設置
NSDictionary *compressionProperties = @{ AVVideoAverageBitRateKey : @(bitsPerSecond),
AVVideoExpectedSourceFrameRateKey : @(15),
AVVideoMaxKeyFrameIntervalKey : @(15),
AVVideoProfileLevelKey : AVVideoProfileLevelH264BaselineAutoLevel };
CGFloat width = kScreenWidth;
CGFloat height = kScreenHeight;
//視頻屬性
NSDictionary *videoCompressionSettings = @{ AVVideoCodecKey : AVVideoCodecTypeH264,
AVVideoWidthKey : @(width * 2),
AVVideoHeightKey : @(height * 2),
AVVideoScalingModeKey : AVVideoScalingModeResizeAspectFill,
AVVideoCompressionPropertiesKey : compressionProperties };
_assetWriterVideoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoCompressionSettings];
//expectsMediaDataInRealTime 必須設為yes，需要從capture session 實時獲取數據
_assetWriterVideoInput.expectsMediaDataInRealTime = YES;
// 音頻設置
NSDictionary *audioCompressionSettings = @{ AVEncoderBitRatePerChannelKey : @(28000),
AVFormatIDKey : @(kAudioFormatMPEG4AAC),
AVNumberOfChannelsKey : @(1),
AVSampleRateKey : @(22050) };
_assetWriterAudioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:audioCompressionSettings];
_assetWriterAudioInput.expectsMediaDataInRealTime = YES;
if ([_assetWriter canAddInput:_assetWriterVideoInput])
{
[_assetWriter addInput:_assetWriterVideoInput];
}
else
{
NSLog(@"AssetWriter videoInput append Failed");
}
if ([_assetWriter canAddInput:_assetWriterAudioInput])
{
[_assetWriter addInput:_assetWriterAudioInput];
}
else
{
NSLog(@"AssetWriter audioInput Append Failed");
}
_canWrite = NO;
}
然后寫入數據
/**
* 開始寫入數據
*/
- (void)appendSampleBuffer:(CMSampleBufferRef)sampleBuffer ofMediaType:(NSString *)mediaType
{
if (sampleBuffer == NULL)
{
NSLog(@"empty sampleBuffer");
return;
}
@autoreleasepool
{
if (!self.canWrite && mediaType == AVMediaTypeVideo && self.assetWriter && self.assetWriter.status != AVAssetWriterStatusWriting)
{
[self.assetWriter startWriting];
[self.assetWriter startSessionAtSourceTime:CMSampleBufferGetPresentationTimeStamp(sampleBuffer)];
self.canWrite = YES;
}
//寫入視頻數據
if (mediaType == AVMediaTypeVideo && self.assetWriterVideoInput.readyForMoreMediaData)
{
if (![self.assetWriterVideoInput appendSampleBuffer:sampleBuffer])
{
@synchronized (self)
{
[self stopVideoRecorder];
}
}
}
//寫入音頻數據
if (mediaType == AVMediaTypeAudio && self.assetWriterAudioInput.readyForMoreMediaData)
{
if (![self.assetWriterAudioInput appendSampleBuffer:sampleBuffer])
{
@synchronized (self)
{
[self stopVideoRecorder];
}
}
}
}
}
結束錄制后保存并預覽播放
/**
* 結束錄制視頻
*/
- (void)stopVideoRecorder
{
__weak __typeof(self)weakSelf = self;
if(_assetWriter && _assetWriter.status == AVAssetWriterStatusWriting)
{
[_assetWriter finishWritingWithCompletionHandler:^{
weakSelf.canWrite = NO;
weakSelf.assetWriter = nil;
weakSelf.assetWriterAudioInput = nil;
weakSelf.assetWriterVideoInput = nil;
}];
}
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3f * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[weakSelf saveVideo];
[weakSelf previewVideoAfterShoot];
});
}
三、保存并播放音視頻
在保存前，需要先將錄制的音視頻數據合成
- (void)cropWithVideoUrlStr:(NSURL *)videoUrl completion:(void (^)(NSURL *outputURL, Float64 videoDuration, BOOL isSuccess))completionHandle
{
AVURLAsset *asset =[[AVURLAsset alloc] initWithURL:videoUrl options:nil];
//獲取視頻總時長
Float64 endTime = CMTimeGetSeconds(asset.duration);
if (endTime > 10)
{
endTime = 10.0f;
}
Float64 startTime = 0;
NSString *outputFilePath = [self createVideoFilePath];
NSURL *outputFileUrl = [NSURL fileURLWithPath:outputFilePath];
NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:asset];
if ([compatiblePresets containsObject:AVAssetExportPresetMediumQuality])
{
AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]
initWithAsset:asset presetName:AVAssetExportPresetPassthrough];
NSURL *outputURL = outputFileUrl;
exportSession.outputURL = outputURL;
exportSession.outputFileType = AVFileTypeMPEG4;
exportSession.shouldOptimizeForNetworkUse = YES;
CMTime start = CMTimeMakeWithSeconds(startTime, asset.duration.timescale);
CMTime duration = CMTimeMakeWithSeconds(endTime - startTime,asset.duration.timescale);
CMTimeRange range = CMTimeRangeMake(start, duration);
exportSession.timeRange = range;
[exportSession exportAsynchronouslyWithCompletionHandler:^{
switch ([exportSession status]) {
case AVAssetExportSessionStatusFailed:
{
NSLog(@"合成失敗：%@", [[exportSession error] description]);
completionHandle(outputURL, endTime, NO);
}
break;
case AVAssetExportSessionStatusCancelled:
{
completionHandle(outputURL, endTime, NO);
}
break;
case AVAssetExportSessionStatusCompleted:
{
completionHandle(outputURL, endTime, YES);
}
break;
default:
{
completionHandle(outputURL, endTime, NO);
} break;
}
}];
}
}
然后再將視頻保存到手機相冊
使用Photos框架保存
/**
保存視頻
*/
- (void)saveVideo
{
[self cropWithVideoUrlStr:self.videoURL completion:^(NSURL *videoUrl, Float64 videoDuration, BOOL isSuccess) {
if (isSuccess)
{
NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];
NSString * assetCollectionName = [infoDictionary objectForKey:@"CFBundleDisplayName"];
if (assetCollectionName == nil)
{
assetCollectionName = @"視頻相冊";
}
__block NSString *blockAssetCollectionName = assetCollectionName;
__block NSURL *blockVideoUrl = videoUrl;
PHPhotoLibrary *library = [PHPhotoLibrary sharedPhotoLibrary];
dispatch_async(dispatch_get_main_queue(), ^{
NSError *error = nil;
__block NSString *assetId = nil;
__block NSString *assetCollectionId = nil;
// 保存視頻到【Camera Roll】(相機膠卷)
[library performChangesAndWait:^{
assetId = [PHAssetChangeRequest creationRequestForAssetFromVideoAtFileURL:blockVideoUrl].placeholderForCreatedAsset.localIdentifier;
} error:&error];
NSLog(@"error1: %@", error);
// 獲取曾經創建過的自定義視頻相冊名字
PHAssetCollection *createdAssetCollection = nil;
PHFetchResult <PHAssetCollection*> *assetCollections = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
for (PHAssetCollection *assetCollection in assetCollections)
{
if ([assetCollection.localizedTitle isEqualToString:blockAssetCollectionName])
{
createdAssetCollection = assetCollection;
break;
}
}
//如果這個自定義框架沒有創建過
if (createdAssetCollection == nil)
{
//創建新的[自定義的 Album](相簿\相冊)
[library performChangesAndWait:^{
assetCollectionId = [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle:blockAssetCollectionName].placeholderForCreatedAssetCollection.localIdentifier;
} error:&error];
NSLog(@"error2: %@", error);
//抓取剛創建完的視頻相冊對象
createdAssetCollection = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[assetCollectionId] options:nil].firstObject;
}
// 將【Camera Roll】(相機膠卷)的視頻 添加到【自定義Album】(相簿\相冊)中
[library performChangesAndWait:^{
PHAssetCollectionChangeRequest *request = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:createdAssetCollection];
[request addAssets:[PHAsset fetchAssetsWithLocalIdentifiers:@[assetId] options:nil]];
} error:&error];
NSLog(@"error3: %@", error);
});
}
else
{
NSLog(@"保存視頻失敗!");
[[NSFileManager defaultManager] removeItemAtURL:self.videoURL error:nil];
self.videoURL = nil;
[[NSFileManager defaultManager] removeItemAtURL:videoUrl error:nil];
}
}];
}
然后就可以去播放了
這里使用AVPlayer來播放
/** 視頻預覽View */
@property (strong, nonatomic) UIView *videoPreviewContainerView;
/** 播放器 */
@property (strong, nonatomic) AVPlayer *player;
- (void)previewVideoAfterShoot
{
if (self.videoURL == nil || self.videoPreviewContainerView != nil)
{
return;
}
AVURLAsset *asset = [AVURLAsset assetWithURL:self.videoURL];
// 初始化AVPlayer
self.videoPreviewContainerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, kScreenWidth, kScreenHeight)];
self.videoPreviewContainerView.backgroundColor = [UIColor blackColor];
AVPlayerItem * playerItem = [AVPlayerItem playerItemWithAsset:asset];
self.player = [[AVPlayer alloc] initWithPlayerItem:playerItem];
AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:self.player];
playerLayer.frame = CGRectMake(0, 0, kScreenWidth, kScreenHeight);
playerLayer.videoGravity = AVLayerVideoGravityResizeAspect;
[self.videoPreviewContainerView.layer addSublayer:playerLayer];
// 其余UI布局設置
[self.view addSubview:self.videoPreviewContainerView];
[self.view bringSubviewToFront:self.videoPreviewContainerView];
// 重復播放預覽視頻
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playVideoFinished:) name:AVPlayerItemDidPlayToEndTimeNotification object:playerItem];
// 開始播放
[self.player play];
}
