前言:前一段时间产品新需求,说是要做微信的小时频功能.
功能需求:360x640 or 640x360的分辨率,大小在2MB 之内的 MP4格式
短视频 demo 地址
思路:使用 AVFoundtion框架提供的 AVCaptureSession进行录制,
大致如下:
摄像头,麦克风(input)->AVCapture Session->AVCaptureVideoDataOutpu(仅视频数据,无音频数据)t,AVCaptureAudioDataOutput(音频数据),AVCaptureStillImageOutput(照片),AVCaptureMovieFileOutput(有视频,也有音频)->AVAssetWriter封装视频和音频格式，写入磁盘，完成录制
关系图.jpg
1.AVCaptureDeviceInput(输入设备):包括摄像头(前置,后置),麦克风,负责采集视频和音频数据
2.AVCaptureVideoDataOutpu:输出视频数据,仅仅只是视频,没有声音,可以对视频格式和参数进行自定义封装和添加滤镜处理
3.AVCaptureAudioDataOutput:输出音频数据,可以对格式和参数进行自定义封装
4.AVCaptureStillImageOutput:照片数据,用户获取静态图像(拍照)
5.AVCaptureMovieFileOutput:输出完整视频(包括音频),优点:录制简单,缺点:可定制性差,短视频不适用(体积太大)
6.AVCapture Session:用于处理输入与输出之间的数据流
7.AVCaptureVideoPreviewLayer:摄像头实时预览 layer, 可以预览摄像头采集的实时视频信息
8.AVAssetWriter:封装音视频格式，写入磁盘
代码示例:
1.录制：
<pre>
- (AVCaptureSession *)recordSession {
if (_recordSession == nil) {
_recordSession = [[AVCaptureSession alloc] init];
_recordSession.sessionPreset = AVCaptureSessionPresetHigh;
//添加后置摄像头的输出
if ([_recordSession canAddInput:self.backCameraInput]) {
[_recordSession addInput:self.backCameraInput];
}
//添加后置麦克风的输出
if ([_recordSession canAddInput:self.audioMicInput]) {
[_recordSession addInput:self.audioMicInput];
}
//添加视频输出
if ([_recordSession canAddOutput:self.videoOutput]) {
[_recordSession addOutput:self.videoOutput];
_cx = VIDEO_WIDTH;
_cy = VIDEO_HEIGHT;
}
//添加音频输出
if ([_recordSession canAddOutput:self.audioOutput]) {
[_recordSession addOutput:self.audioOutput];
}
// 静态图像输出
if ([_recordSession canAddOutput:self.stillImageOutput]) {
[_recordSession addOutput:self.stillImageOutput];
}
//设置视频录制的方向
self.videoConnection.videoOrientation = AVCaptureVideoOrientationPortrait;
}
return _recordSession;
}
//后置摄像头输入
- (AVCaptureDeviceInput *)backCameraInput {
if (_backCameraInput == nil) {
NSError *error;
_backCameraInput = [[AVCaptureDeviceInput alloc] initWithDevice:[self backCamara] error:&error];
if (error) {
NSLog(@"获取后置摄像头失败~");
}
}
return _backCameraInput;
}
//前置摄像头输入
- (AVCaptureDeviceInput *)frontCameraInput {
if (_frontCameraInput == nil) {
NSError *error;
_frontCameraInput = [[AVCaptureDeviceInput alloc] initWithDevice:[self frontCamara] error:&error];
if (error) {
NSLog(@"获取前置摄像头失败~");
}
}
return _frontCameraInput;
}
//麦克风输入
- (AVCaptureDeviceInput *)audioMicInput {
if (_audioMicInput == nil) {
AVCaptureDevice *mic = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
NSError *error;
_audioMicInput = [AVCaptureDeviceInput deviceInputWithDevice:mic error:&error];
if (error) {
NSLog(@"获取麦克风失败~");
}
}
return _audioMicInput;
}
//视频输出
- (AVCaptureVideoDataOutput )videoOutput {
if (_videoOutput == nil) {
_videoOutput = [[AVCaptureVideoDataOutput alloc] init];
[_videoOutput setSampleBufferDelegate:self queue:self.captureQueue];
NSDictionary setcapSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange], kCVPixelBufferPixelFormatTypeKey,
nil];
_videoOutput.videoSettings = setcapSettings;
}
return _videoOutput;
}
//音频输出
- (AVCaptureAudioDataOutput *)audioOutput {
if (_audioOutput == nil) {
_audioOutput = [[AVCaptureAudioDataOutput alloc] init];
[_audioOutput setSampleBufferDelegate:self queue:self.captureQueue];
}
return _audioOutput;
}
//静态图像输出
- (AVCaptureStillImageOutput *)stillImageOutput{
if (_stillImageOutput == nil) {
_stillImageOutput = [[AVCaptureStillImageOutput alloc]init];
_stillImageOutput.outputSettings = @{AVVideoCodecKey:AVVideoCodecJPEG};
}
return _stillImageOutput;
}
//视频连接 - (AVCaptureConnection *)videoConnection {
_videoConnection = [self.videoOutput connectionWithMediaType:AVMediaTypeVideo];
return _videoConnection;
}
//音频连接
- (AVCaptureConnection *)audioConnection {
if (_audioConnection == nil) {
_audioConnection = [self.audioOutput connectionWithMediaType:AVMediaTypeAudio];
}
return _audioConnection;
}
//捕获到的视频呈现的layer
- (AVCaptureVideoPreviewLayer *)previewLayer {
if (_previewLayer == nil) {
//通过AVCaptureSession初始化
AVCaptureVideoPreviewLayer *preview = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.recordSession];
//设置比例为铺满全屏
preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
_previewLayer = preview;
}
return _previewLayer;
}
//录制的队列
- (dispatch_queue_t)captureQueue {
if (_captureQueue == nil) {
_captureQueue = dispatch_queue_create("cn.qiuyouqun.im.wclrecordengine.capture", DISPATCH_QUEUE_SERIAL);
}
return _captureQueue;
}
</pre>
2.格式封装和配置参数
<pre>
//初始化视频输入
-
(void)initVideoInputHeight:(NSInteger)cy width:(NSInteger)cx {
//录制视频的一些配置，分辨率，编码方式等等
NSInteger numPixels = cx * cy;
//每像素比特
CGFloat bitsPerPixel = 6.0;
NSInteger bitsPerSecond = numPixels * bitsPerPixel;// 码率和帧率设置
NSDictionary compressionProperties = @{ AVVideoAverageBitRateKey:@(bitsPerSecond),
AVVideoExpectedSourceFrameRateKey:@(30),
AVVideoMaxKeyFrameIntervalKey:@(30),
AVVideoProfileLevelKey:AVVideoProfileLevelH264BaselineAutoLevel };
NSDictionary settings = @{AVVideoCodecKey:AVVideoCodecH264,
AVVideoScalingModeKey:AVVideoScalingModeResizeAspectFill,
AVVideoWidthKey:@(cx),
AVVideoHeightKey:@(cy),
AVVideoCompressionPropertiesKey:compressionProperties };//初始化视频写入类
_videoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:settings];
_videoInput.transform = [self transformFromCurrentVideoOrientationToOrientation:AVCaptureVideoOrientationPortrait];
//表明输入是否应该调整其处理为实时数据源的数据
_videoInput.expectsMediaDataInRealTime = YES;
//将视频输入源加入
if ([_writer canAddInput:_videoInput]) {
[_writer addInput:_videoInput];
}
}
//初始化音频输入
- (void)initAudioInputChannels:(int)ch samples:(Float64)rate {
//音频的一些配置包括音频各种这里为AAC,音频通道、采样率和音频的比特率
NSDictionary *settings = @{AVEncoderBitRatePerChannelKey:@(28000),
AVFormatIDKey:@(kAudioFormatMPEG4AAC),
AVNumberOfChannelsKey:@(1),
AVSampleRateKey:@(22050) };
//初始化音频写入类
_audioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:settings];
//表明输入是否应该调整其处理为实时数据源的数据
_audioInput.expectsMediaDataInRealTime = YES;
//将音频输入源加入
[_writer addInput:_audioInput];
}
</pre>
3.视频方向控制
<pre>
- (CMMotionManager *)motionManager{
if (!_motionManager) {
_motionManager = [[CMMotionManager alloc]init];
_motionManager.deviceMotionUpdateInterval = MOTION_UPDATE_INTERVAL;
}
return _motionManager;
}
// 开始 - (void)startDeviceMotionUpdates{
if (_motionManager.deviceMotionAvailable) {
[_motionManager startDeviceMotionUpdatesToQueue:[NSOperationQueue currentQueue] withHandler:^(CMDeviceMotion * _Nullable motion, NSError * _Nullable error) {
[self performSelectorOnMainThread:@selector(handleDeviceMotion:) withObject:motion waitUntilDone:YES];
}];
}
}
// 结束 - (void)stopDeviceMotionUpdates{
[_motionManager stopDeviceMotionUpdates];
} - (void)handleDeviceMotion:(CMDeviceMotion *)deviceMotion{
double x = deviceMotion.gravity.x;
double y = deviceMotion.gravity.y;
if (fabs(y) >= fabs(x))
{
if (y >= 0){
_deviceOrientation = UIDeviceOrientationPortraitUpsideDown;
_videoOrientation = AVCaptureVideoOrientationPortraitUpsideDown;
//NSLog(@"UIDeviceOrientationPortraitUpsideDown--AVCaptureVideoOrientationPortraitUpsideDown");
}
else{
_deviceOrientation = UIDeviceOrientationPortrait;
_videoOrientation = AVCaptureVideoOrientationPortrait;
//NSLog(@"UIDeviceOrientationPortrait--AVCaptureVideoOrientationPortrait");
}
}
else{
if (x >= 0){
_deviceOrientation = UIDeviceOrientationLandscapeRight;
_videoOrientation = AVCaptureVideoOrientationLandscapeRight;
//NSLog(@"UIDeviceOrientationLandscapeRight--AVCaptureVideoOrientationLandscapeRight");
}
else{
_deviceOrientation = UIDeviceOrientationLandscapeLeft;
_videoOrientation = AVCaptureVideoOrientationLandscapeLeft;
// NSLog(@"UIDeviceOrientationLandscapeLeft--AVCaptureVideoOrientationLandscapeLeft");
}
}
;
if (_delegate && [_delegate respondsToSelector:@selector(motionManagerDeviceOrientation:)]) {
[_delegate motionManagerDeviceOrientation:_deviceOrientation];
}
}
// 调整设备取向 - (AVCaptureVideoOrientation)currentVideoOrientation{
AVCaptureVideoOrientation orientation;
switch ([SGMotionManager sharedManager].deviceOrientation) {
case UIDeviceOrientationPortrait:
orientation = AVCaptureVideoOrientationPortrait;
break;
case UIDeviceOrientationLandscapeRight:
orientation = AVCaptureVideoOrientationLandscapeLeft;
break;
case UIDeviceOrientationPortraitUpsideDown:
orientation = AVCaptureVideoOrientationPortraitUpsideDown;
break;
default:
orientation = AVCaptureVideoOrientationLandscapeRight;
break;
}
return orientation;
}
</pre>
PS: 以上只是贴出了部分代码片段,完整代码请看 demo
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